The goal of cryptanalysis is to find some weakness or insecurity in a cryptographic scheme, thus permitting its subversion or evasion.

There are a wide variety of cryptanalytic attacks, and they can be classified in any of several ways. A common distinction turns on what an attacker knows and what capabilities are available. In a ciphertext-only attack, the cryptanalyst has access

only to the ciphertext (good modern cryptosystems are usually effectively immune to ciphertext-only attacks). In a known-plaintext attack, the

cryptanalyst has access to a ciphertext and its corresponding plaintext (or to riesgos del consumo de viagra many such pairs). In a chosen-plaintext attack, the cryptanalyst may commander viagra pas cher choose a plaintext and learn its corresponding ciphertext (perhaps many times) and in a chosen-ciphertext attack, the cryptanalyst may be able to choose ciphertexts and

learn their corresponding plaintexts. Also important, often overwhelmingly so, are mistakes generally in the

design or use of one of the protocols involved.

At CRG, the group members are working on the cryptanalysis of a number of widely known symmetric and asymmetric ciphers.