Pseudorandom Number Generation Functions

Many cryptographic systems rely on pseudorandom number generation functions in their design that make the unpredictable nature inherited from a pseudorandom number generator the security foundation to ensure safe communication over open channels and protection against potential adversaries.

This section describes functions that make the pseudorandom bit sequence generator implemented by a US FIPS-approved method and based on a SHA-1 one-way hash function specified by [FIPS PUB 186-2], appendix 3.

The application code for generating a sequence of pseudorandom bits should perform the following sequence of operations:

1. Call the function PRNGGetSize to get the size required to configure the IppsPRNGState context.
2. Ensure that the required memory space is properly allocated. With the allocated memory, call the PRNGInit function to set up the default value of the parameters for pseudorandom generation process.
3. If the default values of the parameters are not satisfied, call the function PRNGSetSeed and/or PRNGSetAugment and/or PRNGSetModulus and/or PRNGSetH0 to reset any of the control pseudorandom generator parameters.
4. Keep calling the function PRNGen or PRNGen_BN to generate pseudo random value of the desired format.
5. Clean up secret data stored in the context.
6. Free the memory allocated for the IppsPRNGState context by calling the operating system memory free service function.