CCHMAC(3) Library Functions Manual CCHMAC(3)

CCHmacInit, CCHmacUpdate, CCHmacFinal, CCHmacCommon HMAC Algorithm Interfaces

These functions are found in libSystem.

#include <CommonCrypto/CommonHMAC.h>

void
CCHmacInit(CCHmacContext *ctx, CCHmacAlgorithm algorithm, const void *key, size_t keyLength);

void
CCHmacUpdate(CCHmacContext *ctx, const void *data, size_t dataLength);

void
CCHmacFinal(CCHmacContext *ctx, void *macOut);

void
CCHmac(CCHmacAlgorithm algorithm, const void *key, size_t keyLength, const void *data, size_t dataLength, void *macOut);

This interface provides access to a number of HMAC algorithms. The following algorithms are available:

kCCHmacAlgSHA1
- HMAC with SHA1 digest
kCCHmacAlgMD5
- HMAC with MD5 digest
kCCHmacAlgSHA256
- HMAC with SHA256 digest
kCCHmacAlgSHA384
- HMAC with SHA384 digest
kCCHmacAlgSHA224
- HMAC with SHA224 digest
kCCHmacAlgSHA512
- HMAC with SHA512 digest

The MAC must be verified by comparing the computed and expected values using () Other comparison functions (e.g. () ) must not be used as they may be vulnerable to practical timing attacks, leading to MAC forgery.

The object declared in this interface, CCHmacContext, provides a handle for use with the () () and () calls to complete the HMAC operation. In addition there is a one shot function, () that performs a complete HMAC on a single piece of data.

These functions are available in OS X 10.5 and later.

CC_MD5(3cc), CC_SHA(3cc), CC_crypto(3cc), CCCrypto(3cc)

March 22, 2007 macOS 14.4