Low area optimization of snow 3g feedback

A cryptoprocessor, comprising:

• a confidentiality block;
• and
• an integrity block operable to produce a 32-bit MAC data word for each of at least one block cipher and at least one stream cipher,
• the confidentiality and integrity blocks coupled to a bus interface through data channels via a multiplexer/demultiplexer (MUX) and first-in-first-out (FIFO) transmitter (TX) and receiver (RX),
• the confidentiality and integrity blocks further coupled to a cipher block through data channels via the MUX,
• the cipher block operable to implement at least one block cipher and at least one stream cipher, and to iterate MULα and DIVα to produce a new MULx block,
• the integrity block operable to implement a first stream cipher algorithm to iteratively update a value EVAL from a message M and five keystream words produced by a first keystream, and a second stream cipher algorithm that recursively XORs words from a generated second keystream.

A method of securing data, comprising:

• in a cryptoprocessor having a confidentiality block and an integrity block operably coupled to a bus interface and cipher block through a plurality of multiplexers and demultiplexers:
• implementing, in the confidentiality block, confidentiality algorithms using ciphering cores as keystream generators, synchronizing plaintext data from a first-in-first-out (FIFO) transmitter (TX), and generating an output datastream to a FIFO receiver (RX);
• in the cipher block, iterating MULα and DIVα to produce a new MULx block;
• implementing, in the integrity block, a first keystream algorithm and iteratively updating a value EVAL from a message M and five keystream words produced by a stream cipher;
• implementing, in the integrity block, a block cipher algorithm;
• and
• in the integrity block, recursively XORing words from a generated second keystream and producing MAC data.