Algorithms of data encryption. Symmetric encryption algorithms. Algorithm of RSA encryption. DES encryption algorithm. Choice of encryption algorithm

In our computer age, mankind increasingly refuses to store information in handwritten or printed form, preferring for this electronic documents. And if earlier simply stealing paper or parchment, now they are hacking electronic information. Themselves of data encryption algorithms have been known since time immemorial. Many civilizations preferred to encrypt their unique knowledge, so that they could only get to a knowledgeable person. But let's see how all this is displayed on our world.

What is a data encryption system?

To begin with, you need to decide what the cryptographic systems are in general. Roughly speaking, this is a special algorithm for recording information that would be understandable only to a certain circle of people.

In this sense, to an outsider, everything that he sees should (and in principle, so it is) seem like a meaningless set of symbols. Only those who know the rules for their location will be able to read such a sequence. As the simplest example, you can define an encryption algorithm with spelling words, say, backwards. Of course, this is the most primitive thing you can think of. It is understood that if you know the rules of recording, you will not be able to restore the original text of the work.

Why is this necessary?

For what it all was invented, probably, it is not necessary to explain. Look, after all, what amounts of knowledge left from ancient civilizations today are encrypted. Either the ancients did not want us to know this, or all this was done, so that people could use them only when they reach the desired level of development - so far this can only be guessed.

However, if we talk about today's world, information protection becomes one of the biggest problems. Judge for yourself, because there are many documents in the same archives that some governments would not like to disseminate, how many secret developments, how many new technologies. But all this, by and large, is the primary goal of the so-called hackers in the classical sense of the term.

Only one phrase comes to mind, which became the classics of Nathan Rothschild's principles of activity: "Who owns the information, he owns the world." And that's why the information has to be protected from prying eyes, so that it is not used by someone else for their own mercenary purposes.

Cryptography: point of reference

Now, before we consider the very structure that any encryption algorithm has, we will plunge into history a little, in those early times when this science was just emerging.

It is believed that the art of data concealment actively began to develop several millennia ago before our era. The primacy is attributed to the ancient Sumerians, King Solomon and the Egyptian priests. Only much later, the same runic signs and symbols appeared to them. But that's interesting: sometimes the algorithm for encrypting texts (and at that time they were encrypted exactly) was that in the same ancient Sumerian cuneiform, one symbol could mean not only one letter, but a whole word, concept or even sentence. Because of this, deciphering such texts even with the availability of modern cryptographic systems that allow to restore the original appearance of any text becomes absolutely impossible. To put it in modern terms, these are rather advanced, as it is now common, symmetric encryption algorithms. We will dwell on them separately.

Modern world: types of encryption algorithms

As for the protection of confidential data in the modern world, it is worthwhile to consider separately those times when computers were unknown to mankind. Not to mention how much the alchemists or the same Templars have transferred to the paper, trying to hide the true texts about the knowledge they know, it is worth remembering that the problem only worsened since the time of communication.

And here, perhaps, the most famous device can be called a German encryption machine of the Second World called "Enigma", which in English means "riddle". Again, this is an example of how symmetric encryption algorithms are used, the essence of which is that the encryptor and the decryptor know the key (algorithm) originally used to hide the data.

Today such cryptosystems are used everywhere. The most striking example is, say, the AES256 encryption algorithm, which is an international standard. From the point of view of computer terminology, it allows the use of a 256-bit key. In general, modern encryption algorithms are quite diverse, and they can be divided into two large classes: symmetric and asymmetric. They, depending on the area of destination, are now very widely used. And the choice of the encryption algorithm directly depends on the tasks and the method of restoring information in its original form. But what is the difference between them?

Symmetric and asymmetric encryption algorithms: what is the difference

Now let's see, what a cardinal difference between such systems, and on what principles their application in practice is built. As is already clear, encryption algorithms are related to geometric concepts of symmetry and asymmetry. What this means, will now be clarified.

The symmetric encryption algorithm DES, developed back in 1977, implies the existence of a single key, which, presumably, is known to two interested parties. Knowing such a key, it is not difficult to apply it in practice, in order to read the same meaningless set of symbols, bringing it, so to speak, in a readable form.

And what are asymmetric encryption algorithms? Two keys are used here, that is, one uses one to encode the source information, another is necessary to decrypt the contents, and it is not necessary that they coincide or are simultaneously located at the encoding and decoding side. For each of them one is enough. Thus, in a very high degree, the entry of both keys into third hands is excluded. However, based on the current situation, for many intruders, thefts of this type are not particularly a problem. Another thing is the search for that key (roughly speaking, the password), which is suitable for decrypting data. And there can be so many variants that even the most modern computer will process them for several decades. As it was stated, none of the computer systems available in the world can hack access to it and get what is called "wiretapping", can not and will not be able in the next decades.

The most famous and often used encryption algorithms

But let's go back to the computer world. What are the main cryptographic algorithms for protecting information at the present stage of development of computer and mobile equipment?

In most countries, the de facto standard is the AES cryptographic system based on a 128-bit key. However, in parallel with it, sometimes the algorithm of RSA encryption is used, which, although it relates to encryption using an open (public) key, is nevertheless one of the most reliable. This, by the way, is proved by all leading specialists, since the system itself is determined not only by the degree of data encryption, but also by the preservation of the integrity of information. As for the early developments, which includes DES encryption algorithm, it is hopelessly obsolete, and attempts to replace it were started in 1997. That's when the new Advanced AES encryption standard (first with a 128-bit key, then with a 256-bit key) arose on its basis.

RSA Encryption

Now let's look at the RSA technology that relates to an asymmetric encryption system. Suppose one subscriber sends another information encrypted with this algorithm.

For encryption, two sufficiently large numbers X and Y are taken, after which their product Z, called the module, is calculated. Then select some extraneous number A, which satisfies the condition: 1

What happens when you transfer? The sender creates an encrypted text, designated as F, with the initial message M, followed by the exponentiation of A and multiplication by the module Z: F = M ** A * (mod Z). The receiver still has to compute a simple example: M = F ** B * (mod Z). Roughly speaking, all these actions are reduced to exponentiation only. The same principle works with the option of creating a digital signature, but the equations here are somewhat more complicated. To avoid hammering the head with algebra, such material will not be cited.

Yes, there to say, if we are chasing the future, not being able to decipher the past. If you look at the world of our millennium, you can see that the same Roman emperor Gaius Julius Caesar used symmetric encryption algorithms in some of his messages. Well, if you look at Leonardo da Vinci, it generally becomes somehow uncomfortable from one realization that in the field of cryptography this person, whose life is covered by a certain flair of secrecy, for centuries surpassed his modernity.

Until now, the so-called "La Gioconda smile" does not give much rest, in which there is something so attractive that modern man can not understand. Incidentally, in the picture relatively recently some characters (in the eye, on a dress, etc.), which clearly indicate that in all this there is some encrypted by a great genius information, which today, alas, we extract unable. But we did not even mention the various types of large-scale constructions that could overturn the understanding of physics of that time.

Of course, some minds tend solely to the fact that in most cases the so-called "golden section" has been used, but it does not give the key to all that huge storehouse of knowledge that is either believed to be incomprehensible or lost forever. Apparently, the cryptographers have yet to do an incredible amount of work to understand that modern encryption algorithms sometimes do not go to any comparison with the workings of ancient civilizations. In addition, if today there are generally accepted principles for the protection of information, then those that were used in antiquity, unfortunately, are completely inaccessible and incomprehensible to us.

One more thing. There is an unspoken opinion that most of the ancient texts can not be translated just because the keys to their decipherment are carefully guarded by secret societies like Masons, Illuminati, etc. Even the Templars left their mark here. What to say that the Vatican library remains absolutely inaccessible until now? Are not there the main clues to understanding antiquity? Many experts are inclined to this version, believing that the Vatican deliberately hides this information from the public. So it or not, until no one knows. But one thing can be said for sure - the ancient cryptography systems were in no way inferior (or, perhaps, superior) to those used in the modern computer world.

Instead of an afterword

Finally, it should be said that not all aspects related to the current cryptographic systems and the methods that they use were considered here. The matter is that in most cases it would be necessary to result in complex mathematical formulas and to present calculations from which most of the users simply head around will go. It is enough to look at an example with the description of the RSA algorithm to realize that everything else will look much more complicated.

The main thing here is to understand and penetrate, so to speak, the essence of the matter. Well, if we talk about modern systems that offer to store confidential information in such a way that it is available to a limited number of users, there is little choice here. Despite the existence of many cryptographic systems, the same algorithms RSA and DES clearly lose the specifics of AES. However, and most of today's applications developed for completely different operating systems, use AES (of course, depending on the field of application and device). But here is the "unauthorized" evolution of this cryptosystem, to put it mildly, many, especially its creators, shocked. But in general, based on what is available today, many users will easily understand what cryptographic data encryption systems are, why they are needed and how they work.