Production Specification

07/03/02

B roa dcom Co rpo rat ion

Document

5802-DS03-405-R

The Operation Type bits must be set as follows:

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0x01 – Diffie-Hellman public key generation operation

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0x02 – Diffie-Hellman shared secret generation operation

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0x03 – RSA public key operation

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0x04 – RSA private key operation (RSA operation with Chinese Remainder Theory)

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0x05 – DSA signing operation

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0x06 – DSA verification operation

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0x41 – RNG direct test mode

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0x42 – RNG-SHA1 test mode

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0x43 – Modular Addition

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0x44 – Modular Subtraction

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0x45 – Modular Multiplication

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0x46 – Modular Reduction (Remainder)

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0x47 – Modular Exponentiation

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0x48 – Modular Inverse

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Other values – Reserved for future use

The number of entries a command context has depends on Operation Type and number of bits used for the operation. The

total_command__context_length field provides the total number of bytes required for the command context structure for a

given key setup or an atomic arithmetic operation. Since the minimum number of bytes required for a PCI access is 64 bytes,

the field should have 64 bytes for the RNG test modes.

For DH public key generation and DSA signing operation, either the on-chip Random Number Generator can be used to

generate x for DH and k for DSA or else the values can be obtained from the software. If they are generated by RNG, the

Provided/RNG Generated (RNG Enable) bits in command context are set to one. Otherwise, they are set to 0. If they are

provided by the application software, then they are stored in data buffers. The chip retrieves them during processing of MCR

structure.

For DSA signing and verification operations, message hash can either be provided by software (CPU does the hashing) or

be performed by SHA1 unit on the chip. If hash is done by SHA1, the Message Hash Provided/Generated (SHA1 Enable)

bits are set to one. Otherwise, they are set to zero. Either the message or the message hash is stored in the input data buffer.

The chip retrieves them during MCR structure processing.

For DH send mode, both public key and private key are generated and stored in the output data buffers in a linked list fashion.

For DH receive mode, both public key and private key are provided for shared secret computation and stored in the input

data buffers in a linked list fashion.

For DSA signing mode, both r and s are generated and stored in output data buffers in a linked list fashion.

For DSA verification mode, both r and s are provided by application and stored in input data buffers in a linked list fashion.

For RNG bypass and RNG-SHA1 modes, there is no input data buffer required and one output data buffer containing the

random numbers. The length of the data buffer is contained in the output buffer length field in MCR.

For atomic operations ModAdd, ModSub, ModMul, ModRem, ModExp, and ModInv, the modulus is passed to the chip via

command context structure and other operands are stored in the input data buffers in a linked list fashion. In typical

applications, modulus does not change for each operation. For ModInv, a modular inverse operation was converted to a

modular exponentiation operation. Because of that, (N-2) is stored where N is the modulus, in the command context.