Concept in Definition ABC

Although it is in our times when encryption and encryption technologies have exploded due to the mass use of smart devices and connection to Internet, encryption techniques have been used since ancient times.

Like so many other things attributed to the great Julius Caesar, he too used a code encryption for his military communications, which may seem very simple and trivial to decipher today, but which at the time must have been terribly complicated:

the Caesar cipher consists of substituting each letter of the alphabet for another, moving the positions a certain number of squares

So, for example, if we have that the alphabet is ABCDEFGHIJK... and we decided to use a Caesar key with displacement of 3 positions, A will correspond to D, B will correspond to E, and so on.

In this way, a text What

Hi how are things

it would look like

Krñd, txh wdñ

The problem with this type of code is that in all languages ​​some letters are repeated more than others. In the descendant languages ​​of Latin they are the vowels, and if we see that a

character It is repeated a lot, we can start testing until we decipher a word. And with some deciphered letters, as we can know the displacement, deciphering the rest of the text will be trivial.

To solve it,

current encryption systems use a series of mathematical operations for the resolution of which keys are needed

These keys are usually public and private. The first is used to decode any message that reaches us, and it is the one that we must have in order to receive encrypted communications and decrypt them to understand them.

The private key is what is needed to encrypt messages, and it is the one that we should not provide to anyone.

An important factor in encoding algorithms is how many bits are used in mathematical operations

since the more they are, that is, the longer the key, the more difficult it is to decode the data, and the greater safety in its transmission. What's more,

to the difficulty of deciphering a coded information is added its "expiration"

Thus, for example, the espionage services of the allied countries during the Second World War, agreed to provide the Germans, through their main double agent (the Catalan Joan Pujol), information on the real plans for the Normandy landing, a few hours before these occurred, when the Germans had no possibility of rectifying and better covering the area.

In this way, and with "expired" practical information, they saved the credibility of their best asset in counterintelligence.

Thus, if we have information encoded with a long key, it may become possible to decode it using very powerful computer systems and using its time, but by that time, the information would no longer be of interest or we would have already obtained it through other public means, with which, even beginning the decoding, it already loses interest.

Among the most popular encryption systems we have:

• DES (Data Encryption Standard)


• AES (Advanced Encryption Standard)


• PGP (Pretty Good Privacy)


• Blowfish


• Twofish

Photos: Fotolia - Cebreros / Corocota

Topics in Encryption