METHOD AND SYSTEM FOR ENCRYPTION

摘要

PURPOSE: To provide a pseudo random function for ciphering, which is efficient in terms of software. CONSTITUTION: A ciphering key is previously processed and the table of pseudo random values is generated (10). One group of initial values for a register are generated by using an index and one group of the values from the table (12). At least a part of the register values takes the present value of the register and the present value is partially corrected by substituting the present value for the function of the present value and a value retrieved from the table. The register values are masked by using other values from the table after correction and results are connected so as to generate a pseudo random bit string. The correction step is repeated, the new masked function of the register value is connected and the pseudo random bit string is generated. The correction step and the connection step are repeated until the string obtains a desired length. Then, the pseudo random bit string can continuously be grown.