Despite the war, life in Ukraine goes on. Recently, the Kiev company Extra Systems announced the creation of a new cryptographic system based on the previously well-known RSA and RC4 encryption algorithms. At the same time, Extra Systems combined these algorithms in such a way that this made this system completely resistant to any kind of hacking.
At the initial stage of establishing a connection, subscribers of the Extra Systems Cypher Net program generate (each on their own computer) two passwords for the RC4 stream encryption algorithm, about 1000 bits long. Then each of the partners encrypts their password with their private RSA key and transmits this encryption over the network. The peculiarity of this encrypted communication system is that the other end of the connection already has our public RSA key, so there is no need to transmit it over the network, as is usually done. The partners exchange public RSA keys in advance (and once) at a personal meeting or through a trusted courier.
Thus, the Extra Systems Cypher Net program does not claim to invent new encryption algorithms (RSA and RC4 have long been known to everyone), but offers a new way of their practical application. The effectiveness of this method lies in the fact that the absence of the public key exchange phase over the network makes it impossible for an attacker who is listening to decrypt the traffic between subscribers. In addition, this completely eliminates the possibility of an attack on the system using the well-known “Man-In-The-Middle” method.
In fact, this is the first working system in the history of cryptography that is not based on the Vernam cipher, which is fundamentally impossible to crack.
The program’s website (in several languages) contains a description of the algorithms and source codes in C.