SetOctString

Developer Reference for Intel® Integrated Performance Primitives Cryptography

Converts octet string into a positive Big Number.

Syntax

IppStatus ippsSetOctString_BN(const Ipp8u* pStr, int strLen, IppsBigNumState* pBN);

Include Files

ippcp.h

Parameters

pStr	Pointer to the input octet string.
strLen	Octet string length in bytes.
pBN	Pointer to the context of the output Big Number.

Description

This function converts an octet string into a positive Big Number.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or warning.
ippStsNullPtrErr	Indicates an error condition if any of the specified pointers is NULL.
ippStsContextMatchErr	Indicates an error condition if the context parameter does not match the operation.
ippStsLengthErr	Indicates an error condition if specified strLen is less than 1.
ippStsSizeErr	Indicates an error condition if insufficient space has been reserved for Big Number.

Example

The code example below shows how to create a big number from a string.

void Set_BN_sample(void){
   // desired value of Big Number is 0x123456789abcdef0fedcba9876543210
   Ipp8u desiredBNvalue[] = "\x12\x34\x56\x78\x9a\xbc\xde\xf0"
                            "\xfe\xdc\xba\x98\x76\x54\x32\x10";
   // estimate required size of Big Number 
   //int size = (sizeof(desiredBNvalue)+3)/4;
   //int size = (sizeof(desiredBNvalue)+3)/4;
   int size = (sizeof(desiredBNvalue)-1+3)/4;
   // and create new (and empty) one
   IppsBigNumState* pBN = New_BN(size);
   // set up the value from the srting
   ippsSetOctString_BN(desiredBNvalue, sizeof(desiredBNvalue)-1, pBN);
   Type_BN("Big Number value is:\n", pBN);
}