RSA Security 5 manual AICBCIV8

AI_CBC_IV8

AI_CBC_IV8

Purpose:

This AI allows you to change the initialization vector (IV) for a CBC-mode cipher without creating a new algorithm object or binding in a new key. This increases the performance of applications that have a long-lived symmetric key (for example, a DES key) used to encrypt many blocks or messages, each with a unique IV.

Type of information this allows you to use:

a new 8-byte initialization vector for an existing CBC algorithm object previously initialized with one of the following AIs:

AI_DES_CBC_IV8, AI_DES_CBCPadIV8, AI_DES_CBCPadBER, AI_DES_CBCPadPEM,

AI_DES_EDE3_CBC_IV8, AI_DES_EDE3_CBCPadIV8, AI_DES_EDE3_CBCPadBER,

AI_DESX_CBC_IV8, AI_DESX_CBCPadIV8, AI_DESX_CBCPadBER, AI_RC2_CBC,

AI_RC2_CBCPad, AI_RC2_CBCPadBER, AI_RC2_CBCPadPEM, AI_RC5_CBC, and

AI_RC5_CBCPad.

Format of info supplied to B_SetAlgorithmInfo:

pointer to an 8-byte unsigned char array containing the new initialization vector.

This new initialization vector will not affect the current algorithm object until the next call to B_EncryptInit, B_EncryptFinal, B_DecryptInit, or B_DecryptFinal.

After the new IV takes effect on the algorithm object, any results from a previous call to B_GetAlgorithmInfo on the algorithm object are undefined.

Format of info returned by B_GetAlgorithmInfo:

B_GetAlgorithmInfo is not supported for AI_CBC_IV8.

Crypto-C procedures to use with algorithm object:

B_SetAlgorithmInfo.

C h a p t e r 2 A l g o r i t h m I n f o Ty p e s 19