Cryptography method for generation of a pseudo-random number and or for encryption or decryption and or for authentication of data using an encryption key and a streaming symmetric cryptographic algorithm

摘要

Method has the following steps: concatenation of an index (i) supplied by a counter with a first sub-key (K2) to form a first data value (D1) of given length; application of the first data value to the input to the algorithm encryption block (E) with a second sub-key (K1) of a different length to generate a second output data value (D2); and execution of an exclusive OR operation bit by bit with a third key (K3) of the same length as the first sub-key to form a pseudo random number as a function of the first, second and third sub-keys. The invention also relates to a corresponding chip card using the inventive encryption technology.