Sunday, 9 June 2019

Analog & Digital Graphing

Well, before we start looking at how we can convert sounds into the electrical pulses that are required to send it along the cables that make up the network, let us consider a few more of the basic things that make up the network. Firstly we will start off with the actual cables, of which there are three types: twisted pair, coaxial, and fibre optic.

Twisted Pair: A twisted pair cable is basically what the name sounds like - two insulated copper wires twisted about each other. The advantage is that they are cheap, but the disadvantage is that not only are they slow, but they really can't send all that much along them - sort of like a really narrow pipe for pumping water. Also, you really don't want to have them running for any really long distances, or even a medium distance for that matter.



Coaxial: This is another form of copper wiring, and is what is generally referred to when people talk about the copper network, particularly when we are talking about the NBN. Look, they are perfectly fine for sending analogue voice signals, but when it comes to high speed broadband, well, they sort of aren't suited for that purpose at all. Basically it is an inner conducting wire, surrounded by insulating material, which in turn is surrounded by a metallic shield, and finally surrounded by another insulating material. ,

By Tkgd2007 - Own work, CC BY 3.0

Fibre Optic: Well, these are the cables that are considered to be at the forefront of data transmission technology. Okay, fibre optic cables have been around for a very long time, but the thing is that they are able to carry huge amounts of traffic at a very high speed. Basically they consist of cables made of glass that are insulated. In fact they will contain multiple cables bundled together. They are also very useful for sending signals long distances, and do so by bouncing the photonic signals along the cable (fibre optic uses light as opposed to electricity as a medium).

The above is what is known as guided media, namely because the signals are guided along a wire. However, we also have unguided media, which is basically radio signals sent across the, well, air. They will normally be sent from a transmitter and picked up by a receiver. The signals will be converted to electro-magnetic signals at the transmitter, and the receiver will pick it up and convert it back.

So, now let us consider the difference between digital and analogue. Basically analogue data takes of a continuous value that changes smoothly over time. Analog signals are measured in hertz (hz), otherwise known as cycles per second. Digital data takes on discrete values, usually in the form of 0s and 1s (and all the other variations that I keep on throwing up). Digital transmission is measured in bits per second. The table below shows an analogue signal on the left and a digital signal on the right.

Analog Graphs


Now, back to sine waves for a bit - they can be measured in either the time domain, or in the frequency domain. As pointed out, frequency is basically cycles per second, so a sine wave, when measured on the frequency domain, will appear different to one that appears on the time domain, as shown below:

Now, the reason we have come back to this is not so much to look at the wave on the time domain, but rather on the frequency domain. The reason for this is because it takes us into the realm of spectrum. The spectrum is the range of frequencies that the signal occupies, and if a number of signals are placed onto a chart along the time domain, we simply come up with a jumble of squiggles. However, if we place it on the frequency domain, we will be able to read it much better. The frequency domain is actually much more useful, and clearer, when it comes to reading multiple sine waves, as the diagram from my lecture notes below shows:


This is particularly useful when the three sine waves have been combined because they will actually produce something different. However, this brings us to the concept of bandwidth, which is basically the width of the spectrum. To calculate a signal's bandwidth, you subtract the highest frequency from the lowest frequency, as the diagram (from my lecture notes) below demonstrates:


So, if we have a sine wave (or actually three sine waves melded together) with frequencies of 100 hz, 300 hz, and 500 hz, and maximum amplitudes of 10 v, 3 v, and 1 v, then the bandwidth would be 500 - 100 = 400 hz, and the frequency graph would be as follows:

Digital Graphs

Well, now that we have considered the analog graphs, let us now turn to digital graphs. First, let us look at the graph:

Now, the bit interval is actually the inverse of the bit rate. So, if we have a bit rate of 2000 bps (bits per second), then the bit rate is 1/2000s = 0.0005 s = 500 μs (micro seconds).

So, now that we have the graphs, next we will move on to sampling.


Creative Commons License

Analog & Digital Graphing by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Saturday, 1 June 2019

All About Blockchain

I remember back in the mid-nineties there was this huge fad sweeping the world. People could see that it was going to be the future, and entrepreneurs were making buckets loads of money off of ideas that in reality had no chance whatsoever of actually making any money. Then, in 1998 the entire house of cards came crashing down. No, I'm not talking about the Asian tiger but rather the growing pains of the internet. Mind you, this was back in the days of dial-up modems and while security algorithms existed there were nowhere on the scale that they are today.

Well, it seems as if the dot.com bust was centuries ago, and we now live in an age where we are wandering around with computers in our pockets that are more powerful than those that sent the original space shuttle into space (and even then the space shuttle is starting to become a distant memory, as is the fall of the Berlin Wall). So, the reason that I am talking about the past is because it seems that we are seeing another technology that has the potential to change the world in which we live, and that is digital currency such as bitcoin.

In fact we have even seen what some could consider to be a bit coin crash, if this chart is anything to go by:

Source: dailyfx.com
I guess anybody who had bought into bitcoin at the beginning of 2018 probably hasn't had all that much of a return on their investment, though the thing is that fads like this happen more often than not, when everybody pours their money into the next big thing, only to discover that the next big thing is nowhere near as great as they anticipated - just ask the Dutch about the tulips.

Anyway, there is more, in fact a lot more, to the concept of blockchain than simply cryptocurrency, though cryptocurrency is basically the thing that pretty much everybody and anybody has heard about, and think about, whenever block chain is mentioned. So, while I might touch upon crypto-currencies, here I'll be looking more at the concept behind it as opposed to the product itself.

So, What is a Blockchain

So, a block chain is a distributed ledger that is shared across a network. Each block chain carries a list of transactions, and a hash that represents all of the previous blocks in the chain. The exception to this is the first block in the chain, known as the genesis block. The way my lecturer explained it is that it is like a spreadsheet, of which there are copies on every single computer in a network. You can add rows to this spreadsheet, but you cannot change any of the existing rows. The reason that blockchain has worked so well with cryptocurrency is that it solves the double spending problem, that is the idea where you can use one bitcoin to purchase something, and then use that exact same bitcoin to then go around and purchase something else.

So, because the blockchains are replicated across a network, it makes them very difficult to corrupt. As such, this means that you can use them in what is known as a 'trustless network'. Basically they can be used even though you do not necessarily trust the source. In being able to do that you no longer need a central authority, such as a central bank in the case of currency, to regulate the chain. In a way the blockchain regulates itself by being able to authenticate itself.


Blockchain in Action

Okay, we already know about cryptocurrency, but they can be a little confusing, and rather complex, so let us look at another use for block chain - logistics. Say we have a company that produces medicine, and that the medicine needs to be kept at, or below, a certain temperature from production to its final destination at the hospital. Previously we would have had to simply trust the paperwork, but block chain actually solves that problem for us.

Basically, at every point in the production line a block is produced, and the temperature is recorded at that point. When the next stage of production commences, a new block is generated, and all of the other blocks are added to this new block. So, we have production, packaging, transportation, and finally retail. Now, just remember that all of this information is being recorded by a computer, so you don't have any dodgy truck drivers, or warehouse managers fiddling the books, so that when the medicine finally arrives at the hospital, the doctors can make sure that the medicine is okay by simply looking at the blocks. If the temperature exceeded a certain height in the process, this will be known.

So, what if the truck driver decided to go back and change the block after it was generated. Well, remember what we said about the hashes in a previous post? Well, these hashes are added to the blocks, so if anybody changes a previous block then this will be noticed since the block that had been changed will not be consistent with the block that had been automatically generated.


In fact, the temperature is just one aspect of this process because you can then also throw in a time frame as well. The time at which the medicine arrives at a certain point in the stage is also recorded, so that if they took too long to put it through one of the stages, this will also be noted in the final block, and the medicine can also be rejected. 

You see, with the traditional method, simply by going back down the chain and asking people you will basically get plausible deniability. The reality is that people, over time, learn that the best way to retain their job is to basically deny everything - in fact that is one of the key aspects of our legal system - denial. What blockchain does is that it allows us to trace where the problem arose, and to then deal with the problem at that point as opposed to attempting to dig up the truth from a bunch of people who are basically being very uncooperative.


You might also note that the hash also contains a private Id. That means that once again, only the section in which the block has been generated can actually create, or change, the block. Without the private Id, access to that particular block, or that particular part of the system, will not be able to happen.

So, here is the block chain that has basically been produced through our hypothetical logistics chain:


Now, what happens is that the temperature during the process went over the maximum value. Well, the auditor, who has full access to all of the blocks, and the private keys to the blocks, can then review each of them to see where the problem occurred. The auditor also knows all of the instructions, and as such is the only one that is able to reproduce the hashes. So, because the auditor can reproduce the hashes, the auditor can not only see that something is wrong, but also where it went wrong. For instance, consider below:


So, from looking at the blocks, the auditor can see that something went wrong with the shipment, and can then approach them and request that they produce their records. However, can the shipment change their records? Well, no, because not only don't they have access to the private key, but further, they do not have access to the retailer's system. In fact, by changing their block will produce an indiscrepancy in not only their block, but the retailer's block as well, which will once again be picked up by the auditor.

In fact there are many uses for block chain, including land registry and health care. The thing is that they all run on the same principle in that all of the previous details are encoded onto the latest details. Further, since they are stored on a distributed system, then one block can be compared with all of the other blocks in a way to prevent fraud. If you change one of the recorded blocks, this will be noticed when you compare it with all of the other blocks that have been stored on the network.

Now, bitcoin works similarly, but there is something else that needs to be considered, if we take into account the diagram below:

So, what is that Merkle Root? Well, I'm glad you asked.

Merkle Trees

Isn't it interesting that a lot of the stuff that I learnt last semester seems to be rearing its ugly head this semester, particularly the stuff from Discrete Maths. The reason I raise this is because of the concept known as the tree. Basically trees are non-cyclical graphs. Now, I'm not going to go into huge details here, but I can refer you elsewhere, such as Wikipedia (that is what is a tree in graph theory). All we need to know here is that a Merkle Tree is basically one of those trees.

So, a Merkle Tree is a hash based data structure where every leaf node is a hash, and every non-leaf node is a hash of its children. In particularly it is the generalisation of a hash tree, and in most cases is implemented as a binary tree. Take the diagram below for instance:

So, each of the leaf nodes is hashed (say that each of the leaves as a transaction that is to be recorded). Then each pair of leaves is then hashed together, and these blocks are then paired off and are hashed together, and this continues until you read the top hash, which contains the hash of all of the nodes below it. This node is known as being the hashed lists of all of the transactions that have taken place since the last block. This is also known as the root hash.

Merkle Trees are used in distributed systems where data verification is paramount. By using hashes instead of full files means that there is a saving when it comes to space. However, because they exist on a distributed system, if a block is changed in one place, then it must be changed everywhere for the change to be valid.

Now, there are two great features with regards to the Merkle Tree. The first is obvious, if we have been following along with regards to the hashes. Namely, if one of the blocks is changed then that change will be reflected all the way up to the root hash. The other aspect is not so obvious - basically if you wish to confirm that something is in the Merkle Tree, you do not need to download the entire tree - you only need to download a part of it. Namely, you only need the block header, and then the path you need to get to the transaction.


So, considering the above, if we want to validate leaf c, all we need is node H(d) and node H(ab). From leaf c, we can recreate node H(c), and then with node H(d) we can recreate node H(cd). Since we also have node H(ab) we can then recreate the root node H(abcd). As such, instead of downloading the entire tree, we only need to download two nodes, and of course the root node for comparison. This is known as 'proof of existence'.

Another example of where a Merkle Tree is used is in a system known as the IPFS, or interplanetary file system. Basically the IPFS is a distributed file sharing system that provides a distributed hash table as a form of catalogue for the files on the system. In a way it is similar to the world wide web, except that is is more like a bit torrent swarm. In fact, the distributed nature of the network means that it is much more resistant to attacks such as DDoS. When a file is added to the network it is referenced through the use of a hash, and it is through this hash that the file can be accessed.

Proof of Work

Now, it is time to start looking at what is known as a consensus mechanism, and in bitcoin this is known as proof of work. Basically a consensus mechanism makes sure that all of the members of a distributed network are the same, and provides a back up if some of the members are beginning to fail. Proof of work is basically a system where miners, through trial and error, seek to reach a consensus to be able to prove that a transaction is valid. Due to the computational power that is required to perform the proof of work, miners are rewarded with bitcoin when the transaction has been verified.

Basically, proof of work involves searching for a nounce (number only once) value that when added to a previous hash will produce a hash that begins with a specific number of 0 bits:


Confused, well, let's go through an example. Say we have a value 1034 and we want to find a hash with 4 zeros. So, we add the number one to our number, producing 10341. We then hash it producing:

859b755563f548d008f936906a959c8f

This is not the hash we want, so we add a 2 instead, producing 10342:

7b3564b05f78b6739d06a2ea3187f5ca

Well, that isn't what we wanted, so let us try a 3:

859b755563f548d008f936906a959c8f

It seems like I could be going on for a very long time if I continue to do it one by one, so let us jump a head and add 599 to produce 1034599:

0000fc70ad0a307d08f88a484dd99cb4

There we go, after 599 hashes we finally have the hash that we were looking for. So, the nounce that we were looking for is 599. This is how it works with bitcoin, and the requirements keep on changing to keep the validation under the 10 minute time frame. It is the search for the nounce that is computationally expensive.

Just for another example, here is a list of hashes, from the sha256, that begin with three zeroes:


Well, this was a pretty long post, but it is a pretty detailed topic of which we have only scratched the surface. The thing is, that as with all new technologies, people seem to want to use it anywhere and everywhere. The reality is though that while blockchain may have a lot of useful characteristics, there may be a lot of situations where it may not be useful at all.
Creative Commons License

All About Blockchain by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Monday, 27 May 2019

Natural Born Losers - The Australian Election

A while back I watched one of Micheal Moore's movie about the election of Donald Trump and one of the things that resonated with me was that the Democrats, well, they just basically don't seem to want to win elections. Well, a part of me feels that this may be the case with the Labor Party here in Australia, though in a way I feel that it is probably a little more complicated than that.


The thing is that the Australian Labor Party has, well, been somewhat unfortunate. For instance, when they defeated Stanley Bruce back in 1929 they suddenly found themselves in the wrong side of a global financial crises, and were immediately kicked out of government at the next election. Look, it wasn't their fault that the entire economy collapsed, but just try convincing the punters of that. In fact, it is quite interesting how history repeated itself because Stanley Bruce not only lost the election, but lost his seat, and it all had to do with changing the employment laws - well in 2007 John Howard did the same thing, and not only did he lose the election, but he also lost his seat, and the very next year there was a global financial crises, probably the worst since the Great Depression. However, Labor did manage to win the next election, but only barely.


Now, come 2019 and surprise surprise, history has once again repeated itself, and in fact there were a lot of hints about history repeating itself. Look, I certainly don't like the Liberal Party, and haven't liked them since John Howard took us to war in Iraq (though a part of me feels that that was going to happen regardless of who was in power at the time). However, if we wind the clock back to 1993 we had a situation where Australia went through a recession, a sitting Prime Minister had been knifed, and the polls all pointed to a Labor defeat. Come election day and the unthinkable happened - Labor won, and the main reason they won - the GST. Yep, the Liberal campaigned on introducing a GST, and Paul Keating took it, and ran with it. In fact, he even stood up in Parliament as pretty much told the Australian people that if the Libs won the election, then they would not block the legislation.

In fact, here is that moment on video:

 

As someone mentioned in the comments, this was the moment Paul Keating won the election. However, despite that, the Libs were still popping open the champagne bottles on the night of the election only to be basically blown away when they discovered that not only had Labor won, but they increased their majority by two seats. Oh, and here is one of the adds that played over the election campaign:



So, the moral of this story is, if you want to lose an election against a deeply unpopular party lead by a deeply unpopular leader, then campaign on tax reform.

Mind you, back in the day, I hated Keating, and I even voted for the Libs, despite the fact that I was a student on student allowance, and would probably have been affected a lot by Hewson's GST, but back in the day I was also pretty ignorant politically. However, as I look back, I have to admit that I do quite like Keating, though I still am somewhat bitter at the fact that he did knife Hawkie in the back.


Billary


Yeah, with Labor leading in the polls for most of this election cycle, and the Libs basically knifing a somewhat popular prime minister, the odds were always in favour of Labor winning this election, though unlike the situation in 1993, Bill Shorten was never really all that popular, no doubt because of his hand in the infighting and leadership spills that defined Labor's last time in office. However, the bookies, and the polls, were all pointing to a Labor victory, Well, as you can probably guess, they lost, which resulted in this meme doing the rounds:




Look, there are a lot of people asking questions as to why they lost, and also lots of people blaming voters for voting against their interests, but in all honesty, I believe they lost for two reasons - tax reform, and the fact that they ran a pretty shocking campaign. In fact, they not only run a campaign where they pretty much played their entire hand, opening them up to attacks from all sides, and further more they seemed to be playing games of me-too - whenever the Coalition raised a policy, they would jump on board, but that certainly wasn't happening the other way. In fact, the whole policy of giving money to young people to buy houses should have been shot down in flames of the pathetic policy that it happens to be, but then again when have any governments been good managers of money?

Yet, in my mind it was the tax reforms, even though they are certainly needed, and it just opened them up to the typical accusations of being the high taxing, big spending party, despite the fact that the Coalition tend to spend just as much, or even more, money than Labor has ever done - hell, they blew a once in a generation mining boom on tax cuts and middle class welfare. Still, it just doesn't seem to stick because, well, people in the end only ever think of their hip pocket.



The Feral Left


One of the interesting things that I have discovered is how the left reacted to the news that the Liberal party won the election. Look, I do sympathise with them in that it certainly appears that we are fighting an uphill battle, but the thing is that in reacting the way that we are we are certainly not winning any friends over to our side. In fact Bob Brown, a former Tasmanian senator for the Greens, led a convoy up to Queensland to protest against a mega mine that is being built there. To say that the reception was rather cold is somewhat of an understatement.


In a way this is the problem that isn't so much faced by the left, but by both sides of politics. The problem is that the extreme right seems to be in positions where their message can be more clearly heard, with shock jocks on the radio, and whole newspapers trumpeting their cause. This isn't all that surprising considering that the conservatives also seem to champion the free market economy, namely because they benefit from increased profits where government regulation isn't in the way.

However, as I mentioned, the left certainly isn't winning any friends my their actions. In fact, by blaming the voters for voting against their interest and suggesting that an entire state be kicked out of Australia is just asking to be alienated even further. Mind you, the fact that the right does seem to be in ascendancy means that we don't get to see their response when the left happens to win, though I have noticed that they do tend to attempt to undermine them more subtly, such as the reports of the non-existent African gangs that happen to be terrorising Western Melbourne.

Yet I still remember when the Libs won the New South Wales election - that didn't go down well at all. The problem was that it turned out that Labor's leader was damaged goods, and despite there being delays and issues with a number of the infrastructure projects, from where I was standing they still seemed to be the better proposition than Labor. I guess that is the thing, namely that instead of blaming the voters, and claiming that the odds are stacked against Labor, one needs to push Labor to actually become electable.

Coal Country

Now, Queensland got a bit of flack from the left leaning city lot, except it goes to show how people don't actually understand what is going on. I went for a walk through parts of outer Brisbane, and you can see that parts of the area that used to be rusted on Labor supporters have become increasingly disillusioned with the party that used to represent them. The thing is that for years Labor was the party of the working person, supported by the unions, but as many of these workers have begun to retire, and as many of the manufacturing jobs have gone overseas, Labor no longer seems to be the answer.

Some have raised the question as to why the poor voted for the Libs as opposed to Labor, and the answer is simple - they don't want a handout, they want a job. You see, if you go and visit some of these parts of Queensland you will discover that these places aren't inhabited by innercity left wing types - they are inhabited by people who do a decent days work, and believe that the best form of welfare is a job. In fact, that is something that I agree with.

Look, there has been a lot of debate about raising the dole and not harassing people who are drawing on welfare, yet there are a lot of people out there that simply use welfare as a form of income that they receive without having to do work. In fact, many people will sit on the dole until the perfect job comes along, not any job, the perfect job. Yeah, that is the problem - the dole isn't there to provide you with an income, it is there to tie you over between jobs, and in reality you really should be out there looking for work, and taking whatever work becomes available.

Now, many of the people in Queensland, and in Western Australia, made a lot of money during the mining boom, and now that period is over. So, we have these options for work, but the party in Canberra is talking about canning this project because it is upsetting a bunch of inner city greenies. Look, I have serious doubts about the economic viability of the Adani mine, and personally, from what I have read, I suspect that the work isn't actually going to materialise, especially since there is talk that it is going to be automated

Palmers $60 Million

Yeah, lets talk about this guy. Look, while I do suspect that he always had the intention of directing votes to the Libs, and running a third party in a system that works on preferential voting, does allow one to register a protest vote, but the thing is that I'm not entirely sure how many people actually follow the how to vote cards, For instance, let us consider the Longman byelection that was held in 2018 - the Libs gained 29% of the vote, Labor 40% of the vote, and One Nation garnerd 15% of the votes, the Green 5%, and pretty much everybody else, well, they comprised of the rest. Now, since we use preferential voting, we go to the two-party preferred which was 55% for Labor and 45% for the Libs. The thing is, even though Clive didn't run a candidate in this election, One Nation did, and they actually received a decent proportion of the vote. However, I'm not quite convinced that the One Nation supporters actually all voted for the Libs (though it is quite possible that they did).

Now, yeah, we have Clive running around trumpeting how he helped the Libs get over the line, especially in Queensland, but honestly, I think he is only making those sounds because of the fact that he spend $60 million dollars in election advertising and did not win a single seat. Look, if this guy actually thinks that people blindly follow the how to vote cards, then this guy really has no idea what he is talking about, or he thinks people are much more stupid than they actually are.

Yeah, people are complaining about how Clive bought the election, but he wants people to be upset - he is that type of guy. Look, we are talking about a guy who ran a mining company into the ground, and left without paying any of the workers a cent. Sure, he may have been a shareholder, and that may excuse him from liability, but the thing is that this guy has more than enough money to pay his workers, but he hasn't. Then there is that coal mine - honestly, if Palmer can't run a Nickle refinery, how on Earth is he going to make money from a coal mine when, well, nobody actually wants to buy coal any more. In fact, the banks don't want to lend to Adani because of the risk that coal is facing, so what makes Clive thing he can succeed where Adani is facing problems.

Oh, and this is also a guy who spend $60 million dollars on election advertising and failed to win a single seat. Look, don't get angry at him, that's what he wants, instead treat him as a joke, and laugh at the fact that he just flushed $60 million dollars down the toilet for no appreciable gain. Why? because the Libs were always going to win that election.


Though, as one friend put it, getting advertising space in those last couple of weeks was pretty hard because Clive had pretty much bought it all up. In a way, as a friend put it, it is like the free beer party at Uni. Basically they have no politics, and simply go around promising everybody free beer if they are elected. The problem is what they are doing is sucking all of the oxygen out of the atmosphere, and preventing anybody else from getting a word in edgewise.

Still, I'm not convinced he had that much of an effect. So, yeah, sure Clive, you didn't buy this election, Bill Shorten lost it because, well, he basically ran a shit campaign. 

The Murdocracy

Honestly, it is starting to get annoying that people are looking at blaming anybody any everybody for Labor's loss with the exception of the one group that is probably responsible for the loss. One of those people that are regularly blamed is Rupert Murdoch, namely because his newspapers account for 65% of all newspapers circulating in Australia. However, the question comes down to whether this control accounts to political control. Honestly, I don't think so.

Now, this concern has arisen since the 2013 election where Labor was basically thrown out of office, and the complaints involved Murdoch publishing newspaper covers as such:


Ever since this front page appeared the left have complained about Murdoch's influence on Australian politics, particularly since two companies control 86% of Australia's newspaper circulation. However, I'm not entirely convinced that Murdoch has as much influence as he believes he has, despite the fact that the Herald Sun is on prominent display in Coles supermarkets, and are also scattered throughout Melbourne's various cafes.

The reason I say this is because in South Australia and Queensland, where there is only one newspaper in circulation, a Murdoch rag, they also happened to have long standing Labor governments. In South Australia, Labor was in power for 16 years, while in Queensland the Liberal government not only managed to get kicked out after one term in office, but they went from literally dominating parliament, to losing by a whisker. So, considering that, and considering how Murdoch seems to trumpet for the Libs, I'm not convinced that his influence is that great.

I could go further and consider the Victorian election where they literally created an African gang crisis that the police claimed did not exist, namely to set up a law and order platform for the liberal opposition. Well, as it turned out, the Libs not only lost, but Labor was returned with a huge majority.

Oh, and when Teresa May called an election in 2017 with the hope of securing a majority in the commons, the result was, well, not they great (she lost 17 seats while Labor gained 34). This was despite the Sun, another Murdoch rag, bearing this headline on the day of the election:


Yeah, I'm not convinced that he has as much influence as people claim he has


How Can Labor Win

I guess that is the big question, and I even wonder if it is possible for them to come back from this, particularly since they seem to have so many other factors stacked up against them. Yet, if we consider the other elections, things are more than possible, and as they say, a week is a very long time in politics.

Here are a few things they should consider, though I do note that Bill Shorten is no longer in the equation, which was one of the reasons I suspect was problematic namely because he really wasn't all that popular.

Retake the Centre
Unfortunately, it seems that the Libs have gone too far to the right, though not so far that they are willing to entertain the likes of Fraser Anning (a senator that was so far to the right that he was kicked out of One Nation). The thing is that with the Libs to the right, and Labor attempting to gain back votes that have drifted to the Greens, I am finding that they are attempting to court a minority while putting off the mainstream voters, who are all going over to the libs.

Well, not quite, because they did get 33% of the vote, but come to think of it, that is pretty shocking. However, he are the counts as they are currently:

Even if all of the UAP and One Nation votes wen to the coalition, that would put them on 48%, while if all the Greens went to Labor, that would by them on 43%. My theory is that they should leave the inner city safe seats and focus on the outer suburb working class seats.

The other thing is that there were all these memes going around the internet, no doubt from the Christians, claiming that Labor was going to introduce all these radical ideas, such as gender neutral driver's licenses, free sex-changes, and free abortions. In my mind, I think that also stuck with certain groups in the centre. In fact, I know of a number of Christian Labor voters who could not bring themselves to vote Labor because of the their intention toward Christian schools.

Leave Kooyong Alone
Honestly, funnelling resources in to the blue ribbon seat on Kooyong really took attention away from where it was needed. Just because there was a huge swing to Labor in Melbourne's leafy suburbs during the state election doesn't mean that it is going to happen in the Federal election. Honestly, leave these seats for the Greens and focus on the heartland of the outer suburbs.

Don't Campaign on Tax 
Yeah, I know, it wasn't at tax, but the thing is that the Libs made sure that people went into the voting booth believing that it was. In fact there are stories of pensioners who believed that they were going to be taxed, when it was only aimed at Franking Credits being paid out to people for no reason other than to buy John Howard votes. Unfortunately, it wasn't going to work, and if there is one thing that I believe cost Labor the election, it was this.

Creative Commons License

Natural Born Losers - The Australian Election by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Sunday, 19 May 2019

Internet Protocols

Basically protocols are the backbone of how the internet works. The thing is that protocols are what you could consider to be a set of standards that everybody follows. I'm not sure if law is the way that you could describe it, procedure is probably a better word. Look, you could do things differently if you really wanted to but in the end your system, unless it is adopted by everybody, simply won't work. You get that in a corporate or office environment - the company has their specific procedures, and if you don't follow those procedures it isn't as if you are going to cause any actual damage, it is just that things won't get done as efficiently as normal - actually, that is probably a bad example considering some company's protocols are pretty poorly designed and implemented, but I hope you understand what I mean - it is more procedure as opposed to law.

The internet has actually been around for quite a while - dating back to 1969 when the United States Department of Defense wanted to develop a way to have computers speak to each other. Actually, the whole idea was to create a system where information could be distributed across a whole region and that the connections would provide a system of redundancy. You could say that it was to create something that could provide a failsafe against a nuclear attack, meaning that if one node was taken out, there would not only be backups, but the other nodes could continue to speak with each other and share information.

From this comes the TCP/IP protocols, or more specifically the Transport Control Protocol/Internet Protocol, and it is this that we will be looking at over these various posts. Mind you there are other protocols out there, but TCP/IP is the standard that basically our world wide web uses to enable you to order a pizza from that really awesome pizza shop on the other side of town (though whether they will actually deliver it to you is another story). Another protocol, UDP, or User Datagram Protocol, is also commonly used, but this protocol really only comes into play when we are doing something like a Facebook Live, namely because it is much more concerned with speed as opposed to accuracy.

Networks

In a nutshell a network is a collection of nodes that are connected by communication links. A node could basically be anything - well not anything because I'm not sure if you could turn a pineapple tree into a node, though honestly, with this internet of things revolution going on, pretty much anything is possible these days. However, in the traditional sense, a node could be anything computer related, such as a computer, a printer, or even a remote storage device. However, as mentioned, this revolution with the internet of things does mean that there are going to be many, many more devices being added to the network in the coming years.

So, we can split networks into three types: Local Area Networks (LAN), Medium Area Networks (MAN), and yes, Wide Area Networks (WAN). Local Area Networks really only exist within an organisation, and are probably referred to as being the Intranet, particularly if you are working for a largish company, as I used to. Generally LANs require access, whether it being physically present within the location, or being invited to use it from the outside. LANs tend to be connected to each other through the use of VPNs, or Virtual Private Networks. This is why many companies are now able to offer the ability for their employees to work from home. Mind you, these VPNs can actually be ridiculously slow at times.

Medium Area Networks sort of sit in the middle ground between the LAN and the WAN. The one major thing with regards to these networks (and this applies to LANs as well) is that they are incredibly fast. Sure, it may sound as if the internet in your local area may be a MAN, but the thing is that they don't actually rely upon the services of the local telephone company. One of the reasons is that with everybody using the service then congestion can be pretty high (try using the wi-fi in a hotel and you will know what I mean). They can be public networks, but can also be private, and generally appear in large corporations or even government entities. For instance, that free wi-fi that the local council offers is probably a MAN.

Finally we have the WAN, which could basically be the internet itself. Yet it might not actually be the case, because these networks are so huge that the mind itself boggles. For instance, the network used by a multi-national corporation could quite easily be a WAN. The thing with WANs is that they don't necessarily provide connection to the nodes across the internet - they might actually have their own private connections that they use, whether it be cable or even satellite (though satellite isn't all that reliable, you know, sunspots and all that).

So, these are the three network types, so let's finish off by looking at the OSI model.

Open Systems Interconnection (OSI) Model

The OSI model was created by the International Standards Organisation as a framework for providing a way for computers to be able to communicate with each other. The model works on the principle that each of the layers has its own functions to perform, and that any changes that occur in one layer will not concern any of the other layers. Basically, the layers will pass a packet down through them, and each of the layers add their own header until such a time that it is sent across the internet. Each of the layers are basically not concerned with what as gone on above, or what will go on below - they are only interested in the functions that occur in their own layer.

As data is passed down through a layer, the layer will add its own header to it, and when the receiver receives the data, each of the layers will strip off the header associated with it and then pass the data up to the next layer, until it reaches the top. Basically each layer relies on the lower layers to perform the more primitive functions, while each of the layers also provides services to the next higher layer. This diagram from my lecture notes may help explain it:

So, let us now go over each of the layers:

Application Layer: this is basically where the program that you are utilising sits. Say, you are sending an email, then the email program is what sits at the application layer, as does the browser that you may be using it through.

Presentation Layer: The data is turned into a human readable form in this layer, though on the way down it is where it is packaged into machine readable form. You could say it is also translation, but it also works to make it pretty. This layer is also where data is compressed to make it's journey across the internet much faster, and more efficient.

Session Layer: This is where each of the sessions are opened, maintained, and closed. It is probably not all that noticeable these days, but back when I was younger, when we would log onto a computer using programs like Telnet, these functions that opened a connection between my computer and the university server occurred at the session layer. In fact, I was doing this much more recently, when I would mount the server onto my computer to enable me to work on my assignments without having to download and upload on a way too regular basis.

Transport Layer: Now, this is where we start to get into the actual communication aspect of the internet. Where as the session layer establishes the connection, the transport layer is where the connection is maintained. Also, it is here that the data is divided into packets to be passed down through to the lower layers, and then across the internet.

Network Layer: It is here that the decisions are made as to where the packets are sent. Basically when a packet hits a node it is passed up to this layer where the ultimate destination is read, and it is then determined which node the packet will then be passed on to.

Data Link Layer: One of the problems with passing data through the internet is that they don't always arrive in the same way that they were sent. This layer is where the error control is handled and it is here where the package is determined whether there is an error or not. This layer is also where the medium access control is located, or the MAC address (more on that later, but every device has its own, unique MAC address).

Physical Layer: Needless to say this is where all of the wires and radio waves are located. However it is more than that because it is here where the transmission medium is decided, and also where the bits are translated into signals, whether it be a radio wave, or simply being passed through a copper, or optical wire.

Source: Understanding the Seven Layers of Computer Networking
The thing is that networks are incredibly complicated beasts, and are made up of routers, software, packages, links, and lots and lots of other things. This is why protocols are required because without them nothing would happen, and nothing would be passed through to another. As such, we wouldn't be able to book the doggy hotel for our pets, or order that drone from an electronics firm. For the internet to work, there needs to be co-operation.

So, this is where the TCP/IP model comes into play. While it is similar to the OSI model, there are new differences. TCP/IP is responsible for adding headers to data and to the packets. However, TCP is only implemented in the end systems, namely your computer and that Google server that you might be accessing to perform your search. The IP however is responsible for getting the data from one end system to the other, and is applied not only in the end systems, but also in all the routers in between. So, the TCP passes the data down to the IP and the IP passes it down to the network. The TCP will add a TCP header, which will turn the data into a TCP segment, and the IP will add an IP header to turn it into an IP datagram. Finally the network will add a network header to turn it into a network packet, which is then sent into the wild world of the internet.

This following diagram will explain the relationship to the two models.

So, that is the basics of the internet protocols. Next we will look at data transmission and sampling.

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Internet Protocols by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Saturday, 11 May 2019

Bestriding the World - Julius Caeser


Well, it seems that I simply cannot get away from watching Shakesperian plays, even if the production is, in my opinion, somewhat sub-par. I am starting to understand why a friend of my really hates going to Australian theatre. Okay, being a regular attendee at theatres of Broadway, and regularly traveling to the United States to go to Shakespeare festivals probably does that to you, and while I have never been to the States, I have been to London, and seen performances in the West End and at the Globe and honestly, these more modern adaptations are really starting to get to me.

I'm not necessarily talking about where the take the play and thrust it into a modern setting, as was the case with Ian McKellan's Richard III and Ralph Fiennes' Coriolanus. Even that version of Macbeth that I refer to as 'Macbeth with Machine Guns' where the quote 'til Birnam Wood remove to Dunsinae' was interpreted as a B-double pulling a trailer full of logs crashing through the gate of some drug lord's manner, only changed the setting as opposed to the actual style. However, as I sat in my seat, with a beer on my hand, watching this latest rendition of Julius Caesar, I could not help but feel that the director has decided to merge classical Shakespeare with modern dance.

Don't get me wrong, I absolutely love the play Julius Caeser, with the lines 'Cry havok and let slip the dogs of war' and 'friends, Romans, countrymen, lend me your ears', and in a way this production very much captialised upon these famous phrases. For instance, when Caeser turns around to see a dagger in Brutus' hand, he pauses, and says 'et tu Brutae'. With Mark Antony's speech, we have a raucous crowd banging on the walls after a rousing oration delivered by Brutus, only to be silenced with the magical words that come out of Mark Antony's mouth. Of course, we even have the beautiful oration delivered by Mark Antony, how he dares not malign Brutus and the other conspirators, but slowly wins them around by reminding them of what Caeser did for them, and that the whole idea of Brutus being an honourable man really means absolutely nothing.


Yet there was something wrong, something that seems to be moving away from the traditional style of play, even the minimalist style that must have been how they were originally performed (well, not quite considering even back in Shakespeare's day, elaborate sets and costumes were still very much the norm - Crash Course has an excellent series on the history of Theatre that is currently running). Sure, the play was very much minimalist with only a single prop on stage that would be moved slightly as the scene changed (it was a billboard on one side, and a pulpit on the other). Yet the actors basically wore modern clothes, and modern music would play in the background, and of course there was this interpretive dance that seemed to be performed as the conspirators piled onto Caeser.

While I would normally give a bit of a background, I don't think that really needs to be done with regards to Caeser. Anyway, I have written another post on this very play, based on another version performed by the Royal Shakespeare Company. Then there is the version from the Globe that is sitting in my cabinet waiting for a time when I can actually get around to watching it, so it isn't one of those plays that is rarely performed. However, I do wonder if there is really all that much more that I can actually say about it, at least more than I could write that hasn't already been said in two blog posts. Yet that is the beauty of Shakespeare - there is always something new to be discovered, something new to be explored, such as the garden in Hamlet that I never picked up previously.

However, as for Caeser's life, here is a great video I found on Youtube, presented by one of the platform's great presenters - Simon Whistler:



Okay, there really isn't much in the way of indepth analysis of the man, just an outline of his life, and not much in the way of the legacy that he left, but they still give us a pretty decent outline of who he was, and I even learnt a number of things about Caeser that I never realised, such as the phrase 'Veni, Vidi, Vici' wasn't said after he conquered Gaul but rather after he put down a rebellion in Asia Minor. Still, this does provide us with a pretty interesting background to the man.

Beware the ides of March

Honestly, despite the fact that Caeser basically dies halfway through the play doesn't mean that he is relegated to the outer wings - he dominates the play from beginning to end. In fact the play is divided into two parts, the first being the conspirators plotting to bring about his downfall, and the second part being his friends seeking revenge for his murder. In fact it seems as if Caeser himself doesn't make all that many appearances in the play, except for the middle where he is led by Crassus from his house to the Senate, and then murdered in the Senate. Yet the play focuses upon this one man almost like a laser light - there are no side plots, no other characters playing around outside of the main focus of his murder - the play is about Julius Caeser and the one person that we are constantly focusing on is Julius Caeser. Even when he isn't on stage, he is still the main focus of the play.

Which is interesting in this particular production since in the original, just prior to the battle, the ghost of Caeser makes an appearance. However in this production the ghost doesn't enter and leave, but he remains right through to the end, even being given speaking parts. In fact the downfall of both Brutus and Crassus are done in sight of the ghost, and even speaking with the ghost. Interestingly, where Brutus stabs Caeser, in the end Brutus holds out his dagger to Caeser so that Caeser may stab him, despite the fact that Caeser is dead.


Then we can't forget the scene where he is offered the crown three times, and rejects the crown three times. That is not played in front of us, but behind the scenes. All we get is a retelling of the events by one of the conspiritors, and another retelling by Mark Antony at the funeral oration. Okay, we hear shouts from outside, but we do not see it. This is an interesting tactic that Shakespeare uses because when we compare the two accounts of the event they couldn't be any different. Mark Anthony does not mention that Caeser had a fit after the third time he was offered the crown, nor does he make mention of the suggestion that Caeser, every time the crown was offered to him, was less reluctant to take it. In a way, looking back at that scene, it makes us cast doubt on the conspirator's account.

He Stride's the World like a Collossus

Isn't it interesting that it is Brutus that is portrayed as the bad guy here, and not Crassus, despite the fact that it is Crassus that is clearly the leader of the conspirators. In a sense, while Crassus could be considered a villain, Brutus is still a traitor, and the worse kind if Dante is to be believed. However, we will get to Brutus soon enough because I really want to say a few things about Crassus here, since he seems to be one of those characters that is particularly important, but seems to fall into Brutus' shadow.

This is not surprising considering that Crassus is one of the patricians, or the old guard to put it another way. He is basically one of the wealthy elite, and like all conservatives, doesn't want to give too much power to the dirty masses (though remembering that this is Rome, so when we talk about dirty masses, we are talking about the poorer citizens - slaves don't count). Yet he is right about Caeser because Caeser is an autocrat. He really doesn't like ruling with anybody, one of the things about the Roman Republic was the desire not to return to the days of the kings, even though that was something like 400 years ago at this stage.


Yet is it right for Crassus to act the way that he does. In a way it is politics, but then again there is this idea that if there is a threat to liberty then violence is a legitimate means in which to maintain that liberty. However, sometimes I feel that the word Freedom is tossed around so much that it's meaning has become lost in the mists of history. What exactly is freedom, and what type of freedom are people talking about - freedom from government interference in our lives, freedom to live the lifestyle that we desire to live, or freedom for business to do business without the government getting in the way. When the conspirators painted 'Freedom' on the board in Caeser's blood after the assassination, I could not help but think that it was a loaded word.

Yet Caeser was an autocrat - there is no denying that. It does not matter whether you are supported by the people or not, and autocrat is still an autocrat. Yet, no matter what the laws say, I still don't think murdering somebody can be justified, no matter what tradition says. Yet this seems to be what Shakespeare is getting at here, because throughout most of his plays, the usurpers never come out on top. This is the case here because the play does not end with Caeser's death, the play ends with the death of the conspirators.

I should say something about Brutus though, however I have already spoken at length about him in my previous blog post. Sure, he is the tragic figure of the play, being torn between his friendship with Caeser and to the legacy of his ancestors. However, he has gone down in history as being one of the greatest of traitors. Dante puts him at the bottom layer of hell along with Judas Iscariot. It is not that be betrayed his country, it is that be betrayed his friend, and not only that, but he even went as far as murdering him. No wonder Brutus couldn't sleep afterwards. In way the name Marcus Brutus is also synonymous with Benedict Arnold.

Friend's, Roman's, Countrymen

And I will finish this off by speaking something of Mark Antony. It is interesting how he is portrayed in this play when in reality Antony was little more than a thug. Sure, I doubt we can really trust Cicero's second Phillipic, which really goes to town on Mark Antony, but I still remember watching a television series on this turbulent period, and Mark Antony really wasn't portrayed in all that great a light. However, Shakespeare doesn't seem to be too concerned about that, instead painting him as a loyal side kick, and one who goes to extreme lengths to revenge his friend's death.

I note that Augustus (actually Octavius) appears in the second half of the play, and accompanies Mark Antony on his crusade against the conspirators. However, he is still playing a minor part at this stage. There is no indication of the power he is to obtain once he disposes of Mark Antony and names himself as Imperator. Here it seems to be taking the position of Antony's side kick, but that isn't all that surprising considering that it was Antony's brilliant speech that rallied the people of Rome to his side. In fact it did much more than that, considering that Shakespeare throws in that scene where the poet Casca is murdered simply for having the same name as a conspirator.

Yet I still can't get it out of my head that Mark Antony is nowhere near as glamorous as he is made out to be here. He isn't a hero, he's a thug, one who almost ran Rome into the ground in Caeser's absence. Okay, it has been over twenty Years since I've read Cicero's Phillipic (actually probably not that long, but it has been a long time), and I suspect that there just might be a lot of truth in what Cicero has to say.

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Bestriding the World - Julius Caeser by David Alfred Sarkies is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me

Saturday, 4 May 2019

Digital Signatures

You know, I must be getting old because I was about to open this post with the words 'back in the day'. The thing is though that I'm not really all that sure if signatures are used as much as they used to be used. These days when it comes to banking transactions we have Personal Identification Numbers, but when I was younger what we had were this little squiggles that we would put at the bottom of a paper as a way so saying either 'I wrote this' or 'I assent to this'. Actually, having been over seas, I have noticed that for some reason when I pay using a credit card I still have to sign the little piece of paper that is spat out of the machine as a means of confirming that I assent to this transaction.

However the problem is that signatures can be forged. The other problem is that when somebody signs something the signature might not be exactly the same, and depending on the person who is requesting the signature, they might either make you jump through hoops to prove that you are who you say you are, or they might handover $1000.00 to the guy who stole your card because, well, they are simply too lazy to check.

So, how does that apply to computer security you ask? Well, we have signatures in the digital world as well, known as digital signatures, and they work similarly to the encryption techniques we looked at previously. However, there is a slight difference. Were a message is encrypted using a public key, and decrypted using a private key, the digital signature is signed using a private key, and verified using a public key. Basically, like the signature that I carried on about above, a digital signature is a means of verifying that you have assented, or sent, something. In fact, that pin number you have to remember for your bank card could quite well be the private key that is used to generate a digital signature that authenticates the purchase, or withdrawal.

In fact, this diagram from the lecture notes is a good explanation of how it works:

Like real world signatures, only the person to whom the signature relates should be capable of actually generating the signature. Another thing is that the document that is signed is usually placed into the signature in the form of a hash as another means of verification.

There are a few ways of generating a digital signature, but we will only look at two of them: RSA and El-Gamal (though this will be the theoretical math component - I'll run through all of what we have done here in a more practical way in a later post, using the Linux terminal of course). Of course, the process in generating a signature is as follows:

  • Sender sets the parameters and generates the public and private keys
  • Sender uses the private key to sign the message
  • Receiver uses the public key to verify the message

RSA Signatures

So, we have a situation where Captain Ed Mercer wants to send an order to the crew of the Orville. Now, as a part of the protocol Ed must sign all of the orders using his digital signature. So, first of all, Ed picks two prime numbers p=17 and q=11. He then generates n by the following method: n=p*q = 187. Ed then calculates φ(n) = (p-1)*(q-1) = 160. Finally Ed picks a number e that is co-prime with φ(n) and that 1 <e < φ(n). Being co-prime, as we remember, means that GCD(φ(n),e) = 1, so Ed picks e=7.



Now that we have all the numbers, Ed sends the public key n and e to the crew of the Orville. Ed then generates the private key d, where d*e = 1 mod φ(n). In this instance d=23, which he retains.

Ed signs the message m=33 as follows:

s = md mod n = 3323 mod 187 = 11.

Now that Ed has his signature, he signs his order and sends it to the crew of the Orville.

Commander Kelly Greyson, who happens to be Ed's 2IC, receives the signed message, and must now verify the message. She does so as follows:

m' = se mod n = 117 mod 187 = 88.

So, the order has been verified, so Kelly passes the order on to the crew.

El-Gamal

Well, it turns out that central command has decided that using RSA for a signature isn't all that secure, and since they are a military outfit, they decided that they will use El-Gamal instead.

So, in this instance, Ed the prime p=11 and the generator g=2, and the private key parameter x=8. Ed then generates the public key y using the following:

y=gx mod p = 28 mod 11 = 3.

Now that Ed has the public key, he sends it through to the Orville.

For the private key, Ed needs to select k where 1 ≼ k  ≼ p-2 where k is co-prime with p-1, or GCD(k,p-1) = 1. Ed decides that k=9 satisfies this criteria. However, it isn't over yet because Ed now needs to generate r as follows:

r=gk mod p = 29 mod 11 = 6

And then sign the message m=5:

s= k-1 (m - x*r) mod (p-1) = 9-1 (-43) mod (10) = 3.

Now that he has the signature s=3, he sends the order to the Orville.

Once again, Kelly receives the order and must verify that it comes from Ed. She does so as follows:

v = gm mod p = 25 mod 11 = 10
w = yr * rs mod p = 38 * 63 mod 11 = 10.

Now, to verify the message, v must equal w, ie: v=w. In this case v=10 and w=10, so the signature has been authenticated.



Now, the reason this provides integrity is because the message m and the signature s are sent together. Now, if the message fails but the signature is okay, then the message has been tampered with, however if the message is okay, but the signature fails, then the signature has been tampered with.

Another thing that signatures provide is non-repudiation. Basically since you are the only one who has the private key, then if you sign a message and send it out you can't then go back on your word. This makes it better than a physical signature, particularly with regards to the concerns over such a signature being forged - in this instance the only way for somebody to forge your signature is to steal your private key.

However, it should be pointed out that we shouldn't be using the same key pair to sign and authenticate a message, and also encrypt the said message. The reason for this is that our hacker could trick us into decrypting a message. For instance, if our hacker sends us a message that they intercepted and requests that it be signed, since we are signing with the private key, we might also be decrypting the message, which means that when we return the message it will actually be plain text.

Digital Certificates

These are certificates that are issues by a trusted third party, such as Verisign. The certificate basically guarantees your authenticity, and in fact are used on a lot of websites. Basically if the certificate is valid, then your browser will allow you to access the site, but if it isn't valid then it was kick up a stick and refuse access (though you can always override it, but not always).

The digital certificate must have the name of the holder, and a public key, but to be helpful it should also be signed by the trusted third party. Beyond that the certificate can pretty much hold anything, though if it has too much information on it, then if any of that information changes a new certificate needs to be issued.


Creative Commons License

This work by Digital Signatures is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on a work at http://www.sarkology.net/. This license only applies to the text and any image that is within the public domain. Any images or videos that are the subject of copyright are not covered by this license. Use of these images are for illustrative purposes only are are not intended to assert ownership. If you wish to use this work commercially please feel free to contact me