OSX/sec/Security/SecPBKDF.c

   1 /*
   2  *  SecPBKDF.c
   3  *
   4  *  Copyright (c) 2010,2012 Apple Inc. All Rights Reserved.
   5  *
   6  */
   7
   8 #include "Security/SecPBKDF.h"
   9 #include "Security/pbkdf2.h"
  10
  11 #include <CommonCrypto/CommonHMAC.h>
  12
  13 #include <string.h>
  14
  15 /* CC Based HMAC PRF functions */
  16 void hmac_sha1_PRF(const uint8_t *key,
  17                    size_t key_len,
  18                    const uint8_t *text,
  19                    size_t text_len,
  20                    uint8_t digest[CC_SHA1_DIGEST_LENGTH])
  21 {
  22     CCHmacContext hmac_sha1_context;
  23
  24     CCHmacInit(&hmac_sha1_context, kCCHmacAlgSHA1, key, key_len);
  25     CCHmacUpdate(&hmac_sha1_context, text, text_len);
  26     CCHmacFinal(&hmac_sha1_context, digest);
  27 }
  28
  29 void hmac_sha256_PRF(const uint8_t *key,
  30                    size_t key_len,
  31                    const uint8_t *text,
  32                    size_t text_len,
  33                    uint8_t digest[CC_SHA256_DIGEST_LENGTH])
  34 {
  35     CCHmacContext hmac_sha256_context;
  36
  37     CCHmacInit(&hmac_sha256_context, kCCHmacAlgSHA256, key, key_len);
  38     CCHmacUpdate(&hmac_sha256_context, text, text_len);
  39     CCHmacFinal(&hmac_sha256_context, digest);
  40 }
  41
  42
  43 /* This implements the HMAC SHA-1 version of pbkdf2 and allocates a local buffer for the HMAC */
  44 void pbkdf2_hmac_sha1(const uint8_t *passwordPtr, size_t passwordLen,
  45                       const uint8_t *saltPtr, size_t saltLen,
  46                       uint32_t iterationCount,
  47                       void *dkPtr, size_t dkLen)
  48 {
  49     // MAX(salt_length + 4, 20 /* SHA1 Digest size */) + 2 * 20;
  50     // salt_length + HASH_SIZE is bigger than either salt + 4 and digestSize.
  51     const size_t kBigEnoughSize = (saltLen + CC_SHA1_DIGEST_LENGTH) + 2 * CC_SHA1_DIGEST_LENGTH;
  52     uint8_t temp_data[kBigEnoughSize];
  53
  54     pbkdf2(hmac_sha1_PRF, CC_SHA1_DIGEST_LENGTH,
  55            passwordPtr, passwordLen,
  56            saltPtr, saltLen,
  57            iterationCount,
  58            dkPtr, dkLen,
  59            temp_data);
  60
  61     bzero(temp_data, kBigEnoughSize);
  62 }
  63
  64 /* This implements the HMAC SHA-256 version of pbkdf2 and allocates a local buffer for the HMAC */
  65 void pbkdf2_hmac_sha256(const uint8_t *passwordPtr, size_t passwordLen,
  66                       const uint8_t *saltPtr, size_t saltLen,
  67                       uint32_t iterationCount,
  68                       void *dkPtr, size_t dkLen)
  69 {
  70     // MAX(salt_length + 4, 32 /* SHA1 Digest size */) + 2 * 32;
  71     // salt_length + HASH_SIZE is bigger than either salt + 4 and digestSize.
  72     const size_t kBigEnoughSize = (saltLen + CC_SHA256_DIGEST_LENGTH) + 2 * CC_SHA256_DIGEST_LENGTH;
  73     uint8_t temp_data[kBigEnoughSize];
  74
  75     pbkdf2(hmac_sha256_PRF, CC_SHA256_DIGEST_LENGTH,
  76            passwordPtr, passwordLen,
  77            saltPtr, saltLen,
  78            iterationCount,
  79            dkPtr, dkLen,
  80            temp_data);
  81
  82     bzero(temp_data, kBigEnoughSize);
  83 }
  84
  85 void SecKeyFromPassphraseDataHMACSHA1(CFDataRef password, CFDataRef salt, uint32_t interationCount, CFMutableDataRef derivedKey)
  86 {
  87     pbkdf2_hmac_sha1(CFDataGetBytePtr(password), CFDataGetLength(password),
  88                      CFDataGetBytePtr(salt), CFDataGetLength(salt),
  89                      interationCount,
  90                      CFDataGetMutableBytePtr(derivedKey), CFDataGetLength(derivedKey));
  91
  92 }
  93
  94 void SecKeyFromPassphraseDataHMACSHA256(CFDataRef password, CFDataRef salt, uint32_t interationCount, CFMutableDataRef derivedKey)
  95 {
  96     pbkdf2_hmac_sha256(CFDataGetBytePtr(password), CFDataGetLength(password),
  97                        CFDataGetBytePtr(salt), CFDataGetLength(salt),
  98                        interationCount,
  99                        CFDataGetMutableBytePtr(derivedKey), CFDataGetLength(derivedKey));
 100
 101 }