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"
14 /* Diversifies key using random UserKey Material
15 * Implements RFC 4357 p 6.5 key diversification algorithm
17 * inputKey - 32byte key to be diversified
18 * ukm - 8byte user key material
19 * outputKey - 32byte buffer to store diversified key
22 void keyDiversifyCryptoPro(gost_ctx *ctx,const unsigned char *inputKey, const unsigned char *ukm, unsigned char *outputKey)
28 memcpy(outputKey,inputKey,32);
31 /* Make array of integers from key */
34 for (j=0,mask=1;j<8;j++,mask<<=1)
36 k=((u4)outputKey[4*j])|(outputKey[4*j+1]<<8)|
37 (outputKey[4*j+2]<<16)|(outputKey[4*j+3]<<24);
47 S[0]=(unsigned char)(s1&0xff);
48 S[1]=(unsigned char)((s1>>8)&0xff);
49 S[2]=(unsigned char)((s1>>16)&0xff);
50 S[3]=(unsigned char)((s1>>24)&0xff);
51 S[4]=(unsigned char)(s2&0xff);
52 S[5]=(unsigned char)((s2>>8)&0xff);
53 S[6]=(unsigned char)((s2>>16)&0xff);
54 S[7]=(unsigned char)((s2>>24)&0xff);
55 gost_key(ctx,outputKey);
56 gost_enc_cfb(ctx,S,outputKey,outputKey,4);
62 * Wraps key using RFC 4357 6.3
63 * ctx - gost encryption context, initialized with some S-boxes
64 * keyExchangeKey (KEK) 32-byte (256-bit) shared key
65 * ukm - 8 byte (64 bit) user key material,
66 * sessionKey - 32-byte (256-bit) key to be wrapped
67 * wrappedKey - 44-byte buffer to store wrapped key
70 int keyWrapCryptoPro(gost_ctx *ctx,const unsigned char *keyExchangeKey, const unsigned char *ukm,
71 const unsigned char *sessionKey, unsigned char *wrappedKey)
73 unsigned char kek_ukm[32];
74 keyDiversifyCryptoPro(ctx,keyExchangeKey,ukm,kek_ukm);
75 gost_key(ctx,kek_ukm);
76 memcpy(wrappedKey,ukm,8);
77 gost_enc(ctx,sessionKey,wrappedKey+8,4);
78 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, unsigned char *sessionKey)
95 unsigned char kek_ukm[32],cek_mac[4];
96 keyDiversifyCryptoPro(ctx,keyExchangeKey,wrappedKey
97 /* First 8 bytes of wrapped Key is ukm */
99 gost_key(ctx,kek_ukm);
100 gost_dec(ctx,wrappedKey+8,sessionKey,4);
101 gost_mac_iv(ctx,32,wrappedKey,sessionKey,32,cek_mac);
102 if (memcmp(cek_mac,wrappedKey+40,4))