Security

We use a 256-bit key, with a unique algorithm for generating it from a key phrase, and we also mix the resulting key according to our algorithm; The linear encryption method is not very convenient for the end user, due to the fact that the user needs to manually generate the key, but it is much safer, unlike RSA encryption (open is the private key). As you know, the well-known Viber, WhatsApp, Telegram messengers are using RSA encryption.

“Why RSA Security recommends using keys with a length of 1024 bits, 2048 bits, and even 3072 bits, while most symmetric encryption algorithms are limited to a length of 112 to 256 bits. Like, why don’t we increase the length of the keys, for example, to a million – in order to protect against potential brutal force from supercomputers that have not yet been invented.

Many still do not have a clear understanding of the difference between an asymmetric cipher and a public key cryptographic algorithm from a symmetric cipher, where the same key is used for encryption and decryption. From the point of view of brute force, the fundamental difference is that to break the RSA key, you need to find a factor of a certain length (and you can use the precomputed tables). This is a mathematical task that can not be very complicated, otherwise the usual decoding of the message will take too much time.

To break a symmetric cipher, you need to go through 2 ^ N combinations, where N is the key length. Decryption of the message in any case occurs instantly, having a symmetric key. According to NIST, a 256-bit symmetric key roughly corresponds to the 15360-bit RSA key. This example is best described in the book “Applied Cryptography” by Bruce Schneier. ”