Abstract

   Cryptographic applications are based on keys for encryption and decryption processes, in order to protect the transferred information between trusted entities. Keys must be strong enough to resist in case of cryptanalytic attacks. Their properties are given by the key generator who is, most of the time, a PRNG (Pseudo-Random Number Generator). Depending on how difficult it is to predict numbers obtained from a generator output, encryption keys can get strong or weak. PRNG periodicity and speed are fundamental factors in the choice of the proper key generator.