Method and system for implementing the A5/3 encryption algorithm for GSM and EDGE compliant handsets

A system for implementing the A5/3 encryption algorithm, the system comprising:

• one or more circuits that enable initializing a keystream generator with input variables;
• said one or more circuits enable generating an intermediate value which is utilized to generate an output keystream, based on said input variables, a cipher key parameter and a key modifier;
• said one or more circuits enable determining a number of processing blocks of output bits based on a number of output bits that are to be generated for said output keystream;
• said one or more circuits enable generating a first processing block of output bits of said determined number of processing blocks of output bits and a signal indicating when said first processing block of output bits is generated;
• said one or more circuits enable generating at least one additional processing block of output bits utilizing an immediately generated previous processing block of output bits, said generated intermediate value, and an indication corresponding to a processing block of output bits being processed, wherein said generating of at least one additional processing block of output bits is done for all subsequent determined number of processing blocks of output bits after a signal indicating when an immediately generated previous processing block of output bits is generated.