Public Key Encryption

Public key cryptosystems (also called asymmetric cryptosystems) are characterized by using different keys for encryption and decryption of information. Its main advantage is that they facilitate the process of distribution and exchange of keys among the participants of secure communication, which was a major problem of symmetric or private key cryptosystems. Asymmetric algorithms generally employ … Read more Public Key Encryption


RSA cryptosystem Among all asymmetric algorithms, RSA is the most used and also perhaps the easiest to understand and implement. A peculiarity of this algorithm is that its two keys serve both to encrypt and to authenticate. It owes its name to its three inventors: Ronald Rivest, Adi Shamir and Leonard Adleman, who first published … Read more RSA

Vigenére Cipher

Vigenère cipher It is a typical example of polyalphabetic encryption whose invention was wrongly attributed to Blaise de Vigenère, and dating back to the 16th century. The key consists of a sequence of symbols of the alphabet K = {k0, k1, …, kd-1}, of length d, and which uses the following linear congruent transformation of … Read more Vigenére Cipher

Substitution Cipher

Monoalphabet substitution encryption A monoalphabet substitution such as César encryption can be expressed by a congruent linear transformation (also known cryptographically as a related transformation). In César encryption, this would be written as E (M) = (M + 3) mod N, where N is the length or cardinal of the original alphabet. The transformation related … Read more Substitution Cipher