37.3.4.13 Get Random Number

The purpose of this command is to provide the user with a source of entropy. The options available for this service are:

• Generation of random numbers from a Hardware Random Number Generator (TRNG).
• Generation of random numbers from a Deterministic Random Number Generator (DRNG).

The DRNG is compatible with both ANSI X9.31 and FIPS 186-2 standards (see the important note below). The DRNG is designed according to:

• The algorithm described in the document ANSI Digital Signatures Using Reversible Public Key Cryptography for the Financial Services Industry (rDSA) X9.31 dated September 9, 1998.
• The Change recommendation for ANSI X9.0 - 1995 (Part 1) and ANSI X9.31 -1998:

The algorithm B.2.1 Algorithm for computing m Values of x is the one applied in the Toolbox 3 X9.31 DRNG. The DRNG is compatible with:

• The DRNG is described in the document NIST Digital Signature Standard (DSS) FIPS Pub 186-2 January 27, 2000 Appendix 3.1
• The FIPS 186-2 Change Notice 1 dated October 5, 2001 modifies this algorithm.

This service has four possible options described in Table 37-41. Two of these options are reserved for future use. This service performs the following operations:

• Generation of a random number from the Hardware RNG
• Generation of a random number from the Deterministic RNG

This service, activated with the option PUKCL_RNG_X931_GET, makes it possible to get a random number R from the Deterministic Random Number Generator with input parameters the Key XKey and the Seed XSeed:

(XKey, R) = DeterministicRandomGenerateFromSeed ( XKey, XSeed, Q)

In the generation of a random number from the Deterministic RNG service, the following parameters need to be provided:

• XKey the input and output Key (pointed by {nu1XKeyBase,u2XKeyLength})
• XSeed the input Seed (pointed by {nu1XseedBase,u2XKeyLength})
• Q the prime number (pointed by {nu1QBase, 20bytes})
• R the generated number area (pointed by {nu1RBase, 20bytes})

The parameters for the generation of random from the Hardware RNG are described in the following table. This service can easily be accessed through the use of the PUKCL_Rng() and PUKCL() macros.

The parameters for the generation of random from the Deterministic RNG are described in the following table. This service can easily be accessed through the use of the PUKCL_Rng() and PUKCL() macros.

PUKCL_PARAM PUKCLParam;
PPUKCL_PARAM pvPUKCLParam = &PUKCLParam;

// ! The Random Number Generator must be initialized and started
// ! following the directives given for the RNG on the chip

PUKCL(u2Option) =...;

// Initializing parameters
PUKCL_Rng(nu1RBase) = <Base of the ram location to store the rng>; 
PUKCL_Rng(u2RLength) = <Length of the rng to get>;

// vPUKCL_Process() is a macro command, which populates the service name
// and then calls the library... 
vPUKCL_Process(Rng,pvPUKCLParam); 
if (PUKCL(u2Status) == PUKCL_OK)
            {
            // The RNG generation has been executed correctly
            ...
            }
else // Manage the error