1 /**********************************************************************
3 * Copyright (c) 2005-2006 Cryptocom LTD *
4 * This file is distributed under the same license as OpenSSL *
6 * Implementation of CryptoPro key wrap algorithm, as defined in *
7 * RFC 4357 p 6.3 and 6.4 *
8 * Doesn't need OpenSSL *
9 **********************************************************************/
12 #include "gost_keywrap.h"
15 * Diversifies key using random UserKey Material
16 * Implements RFC 4357 p 6.5 key diversification algorithm
18 * inputKey - 32byte key to be diversified
19 * ukm - 8byte user key material
20 * outputKey - 32byte buffer to store diversified key
23 void keyDiversifyCryptoPro(gost_ctx * ctx, const unsigned char *inputKey,
24 const unsigned char *ukm, unsigned char *outputKey)
27 memcpy(outputKey, inputKey, 32);
28 for (i = 0; i < 8; i++) {
33 /* Make array of integers from key */
35 for (j = 0, mask = 1; j < 8; j++, mask <<= 1) {
37 k = ((u4) outputKey[4 * j]) | (outputKey[4 * j + 1] << 8) |
38 (outputKey[4 * j + 2] << 16) | (outputKey[4 * j + 3] << 24);
45 S[0] = (unsigned char)(s1 & 0xff);
46 S[1] = (unsigned char)((s1 >> 8) & 0xff);
47 S[2] = (unsigned char)((s1 >> 16) & 0xff);
48 S[3] = (unsigned char)((s1 >> 24) & 0xff);
49 S[4] = (unsigned char)(s2 & 0xff);
50 S[5] = (unsigned char)((s2 >> 8) & 0xff);
51 S[6] = (unsigned char)((s2 >> 16) & 0xff);
52 S[7] = (unsigned char)((s2 >> 24) & 0xff);
53 gost_key(ctx, outputKey);
54 gost_enc_cfb(ctx, S, outputKey, outputKey, 4);
59 * Wraps key using RFC 4357 6.3
60 * ctx - gost encryption context, initialized with some S-boxes
61 * keyExchangeKey (KEK) 32-byte (256-bit) shared key
62 * ukm - 8 byte (64 bit) user key material,
63 * sessionKey - 32-byte (256-bit) key to be wrapped
64 * wrappedKey - 44-byte buffer to store wrapped key
67 int keyWrapCryptoPro(gost_ctx * ctx, const unsigned char *keyExchangeKey,
68 const unsigned char *ukm,
69 const unsigned char *sessionKey,
70 unsigned char *wrappedKey)
72 unsigned char kek_ukm[32];
73 keyDiversifyCryptoPro(ctx, keyExchangeKey, ukm, kek_ukm);
74 gost_key(ctx, kek_ukm);
75 memcpy(wrappedKey, ukm, 8);
76 gost_enc(ctx, sessionKey, wrappedKey + 8, 4);
77 gost_mac_iv(ctx, 32, ukm, sessionKey, 32, wrappedKey + 40);
82 * Unwraps key using RFC 4357 6.4
83 * ctx - gost encryption context, initialized with some S-boxes
84 * keyExchangeKey 32-byte shared key
85 * wrappedKey 44 byte key to be unwrapped (concatenation of 8-byte UKM,
86 * 32 byte encrypted key and 4 byte MAC
88 * sessionKEy - 32byte buffer to store sessionKey in
89 * Returns 1 if key is decrypted successfully, and 0 if MAC doesn't match
92 int keyUnwrapCryptoPro(gost_ctx * ctx, const unsigned char *keyExchangeKey,
93 const unsigned char *wrappedKey,
94 unsigned char *sessionKey)
96 unsigned char kek_ukm[32], cek_mac[4];
97 keyDiversifyCryptoPro(ctx, keyExchangeKey, wrappedKey
98 /* First 8 bytes of wrapped Key is ukm */
100 gost_key(ctx, kek_ukm);
101 gost_dec(ctx, wrappedKey + 8, sessionKey, 4);
102 gost_mac_iv(ctx, 32, wrappedKey, sessionKey, 32, cek_mac);
103 if (memcmp(cek_mac, wrappedKey + 40, 4)) {