Large Random Numbers - Cryptography in C and C++ - page 274

Function: initialization of the RIPEMD-160/SHA-1 pseudorandom

number generator together with entropy creation

Syntax:

int
InitRandRMDSHA1_l (STATERMDSHA1 *rstate, char * UsrStr,
int LenUsrStr, int AddEntropy);

rstate (pointer to state memory)
UsrStr (pointer to user character string)
LenUsrStr (length of the user character string in bytes)
AddEntropy (number of additional requested entropy bytes)

Input:

rstate (pointer to initialized state memory) Output:

Return: 0 if all O.K.

n> 0 : number of requested but not generated entropy bytes

int
InitRandRMDSHA1_l (STATERMDSHA1 *rstate, char *UsrStr,
int LenUsrStr, int AddEntropy)

{

int MissingEntropy;

Generation of start value. In MissingEntropy is stored the number of requested
entropy bytes that were not available.

MissingEntropy = GetEntropy_l (NULL, rstate->XRMDSHA1, AddEntropy,
UsrStr, LenUsrStr);

First state transition, creation of start state.

ripemd160_l (rstate->XRMDSHA1, rstate->XRMDSHA1, 20);

Initialization of the step counter i .

rstate->RoundRMDSHA1 = 1;

Set the initialization flag.