1f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* LibTomCrypt, modular cryptographic library -- Tom St Denis
2f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *
3f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * LibTomCrypt is a library that provides various cryptographic
4f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * algorithms in a highly modular and flexible manner.
5f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *
6f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The library is free for all purposes without any express
7f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * guarantee it works.
8f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *
9f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project */
11f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#include "tomcrypt.h"
12f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
13f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/**
14f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @file dsa_encrypt_key.c
15f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  DSA Crypto, Tom St Denis
16f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/
17f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
18f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef MDSA
19f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
20f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/**
21f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  Encrypt a symmetric key with DSA
22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param in         The symmetric key you want to encrypt
23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param inlen      The length of the key to encrypt (octets)
24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param out        [out] The destination for the ciphertext
25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param outlen     [in/out] The max size and resulting size of the ciphertext
26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param prng       An active PRNG state
27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param wprng      The index of the PRNG you wish to use
28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param hash       The index of the hash you want to use
29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @param key        The DSA key you want to encrypt to
30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project  @return CRYPT_OK if successful
31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project*/
32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint dsa_encrypt_key(const unsigned char *in,   unsigned long inlen,
33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                          unsigned char *out,  unsigned long *outlen,
34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                          prng_state *prng, int wprng, int hash,
35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                          dsa_key *key)
36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{
37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    unsigned char *expt, *skey;
38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    void          *g_pub, *g_priv;
39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    unsigned long  x, y;
40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    int            err;
41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    LTC_ARGCHK(in      != NULL);
43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    LTC_ARGCHK(out     != NULL);
44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    LTC_ARGCHK(outlen  != NULL);
45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    LTC_ARGCHK(key     != NULL);
46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* check that wprng/cipher/hash are not invalid */
48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       return err;
50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = hash_is_valid(hash)) != CRYPT_OK) {
53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       return err;
54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if (inlen > hash_descriptor[hash].hashsize) {
57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       return CRYPT_INVALID_HASH;
58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* make a random key and export the public copy */
61f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = mp_init_multi(&g_pub, &g_priv, NULL)) != CRYPT_OK) {
62f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       return err;
63f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
64f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
65f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    expt       = XMALLOC(mp_unsigned_bin_size(key->p) + 1);
66f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    skey       = XMALLOC(MAXBLOCKSIZE);
67f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if (expt == NULL  || skey == NULL) {
68f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       if (expt != NULL) {
69f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project          XFREE(expt);
70f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       }
71f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       if (skey != NULL) {
72f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project          XFREE(skey);
73f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       }
74f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       mp_clear_multi(g_pub, g_priv, NULL);
75f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       return CRYPT_MEM;
76f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
77f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
78f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* make a random x, g^x pair */
79f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    x = mp_unsigned_bin_size(key->q);
80f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if (prng_descriptor[wprng].read(expt, x, prng) != x) {
81f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       err = CRYPT_ERROR_READPRNG;
82f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       goto LBL_ERR;
83f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
84f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
85f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* load x */
86f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = mp_read_unsigned_bin(g_priv, expt, x)) != CRYPT_OK) {
87f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       goto LBL_ERR;
88f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
89f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
90f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* compute y */
91f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = mp_exptmod(key->g, g_priv, key->p, g_pub)) != CRYPT_OK) {
92f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       goto LBL_ERR;
93f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
94f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
95f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* make random key */
96f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    x        = mp_unsigned_bin_size(key->p) + 1;
97f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = dsa_shared_secret(g_priv, key->y, key, expt, &x)) != CRYPT_OK) {
98f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       goto LBL_ERR;
99f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
100f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
101f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    y = MAXBLOCKSIZE;
102f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    if ((err = hash_memory(hash, expt, x, skey, &y)) != CRYPT_OK) {
103f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project       goto LBL_ERR;
104f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
105f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
106f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* Encrypt key */
107f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    for (x = 0; x < inlen; x++) {
108f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project      skey[x] ^= in[x];
109f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    }
110f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
111f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    err = der_encode_sequence_multi(out, outlen,
112f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                                    LTC_ASN1_OBJECT_IDENTIFIER,  hash_descriptor[hash].OIDlen,   hash_descriptor[hash].OID,
113f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                                    LTC_ASN1_INTEGER,            1UL,                            g_pub,
114f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                                    LTC_ASN1_OCTET_STRING,       inlen,                          skey,
115f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project                                    LTC_ASN1_EOL,                0UL,                            NULL);
116f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
117f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source ProjectLBL_ERR:
118f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef LTC_CLEAN_STACK
119f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    /* clean up */
120f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    zeromem(expt,   mp_unsigned_bin_size(key->p) + 1);
121f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    zeromem(skey,   MAXBLOCKSIZE);
122f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif
123f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
124f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    XFREE(skey);
125f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    XFREE(expt);
126f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
127f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    mp_clear_multi(g_pub, g_priv, NULL);
128f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project    return err;
129f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project}
130f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
131f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif
132f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_encrypt_key.c,v $ */
133f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.7 $ */
134f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/12/04 03:18:43 $ */
135f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project
136