| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com |
| */ |
| |
| /* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b |
| * |
| * All curves taken from NIST recommendation paper of July 1999 |
| * Available at http://csrc.nist.gov/cryptval/dss.htm |
| */ |
| #include "tomcrypt.h" |
| |
| /** |
| @file ecc_encrypt_key.c |
| ECC Crypto, Tom St Denis |
| */ |
| |
| #ifdef MECC |
| |
| /** |
| Encrypt a symmetric key with ECC |
| @param in The symmetric key you want to encrypt |
| @param inlen The length of the key to encrypt (octets) |
| @param out [out] The destination for the ciphertext |
| @param outlen [in/out] The max size and resulting size of the ciphertext |
| @param prng An active PRNG state |
| @param wprng The index of the PRNG you wish to use |
| @param hash The index of the hash you want to use |
| @param key The ECC key you want to encrypt to |
| @return CRYPT_OK if successful |
| */ |
| int ecc_encrypt_key(const unsigned char *in, unsigned long inlen, |
| unsigned char *out, unsigned long *outlen, |
| prng_state *prng, int wprng, int hash, |
| ecc_key *key) |
| { |
| unsigned char *pub_expt, *ecc_shared, *skey; |
| ecc_key pubkey; |
| unsigned long x, y, pubkeysize; |
| int err; |
| |
| LTC_ARGCHK(in != NULL); |
| LTC_ARGCHK(out != NULL); |
| LTC_ARGCHK(outlen != NULL); |
| LTC_ARGCHK(key != NULL); |
| |
| /* check that wprng/cipher/hash are not invalid */ |
| if ((err = prng_is_valid(wprng)) != CRYPT_OK) { |
| return err; |
| } |
| |
| if ((err = hash_is_valid(hash)) != CRYPT_OK) { |
| return err; |
| } |
| |
| if (inlen > hash_descriptor[hash].hashsize) { |
| return CRYPT_INVALID_HASH; |
| } |
| |
| /* make a random key and export the public copy */ |
| if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) { |
| return err; |
| } |
| |
| pub_expt = XMALLOC(ECC_BUF_SIZE); |
| ecc_shared = XMALLOC(ECC_BUF_SIZE); |
| skey = XMALLOC(MAXBLOCKSIZE); |
| if (pub_expt == NULL || ecc_shared == NULL || skey == NULL) { |
| if (pub_expt != NULL) { |
| XFREE(pub_expt); |
| } |
| if (ecc_shared != NULL) { |
| XFREE(ecc_shared); |
| } |
| if (skey != NULL) { |
| XFREE(skey); |
| } |
| ecc_free(&pubkey); |
| return CRYPT_MEM; |
| } |
| |
| pubkeysize = ECC_BUF_SIZE; |
| if ((err = ecc_export(pub_expt, &pubkeysize, PK_PUBLIC, &pubkey)) != CRYPT_OK) { |
| ecc_free(&pubkey); |
| goto LBL_ERR; |
| } |
| |
| /* make random key */ |
| x = ECC_BUF_SIZE; |
| if ((err = ecc_shared_secret(&pubkey, key, ecc_shared, &x)) != CRYPT_OK) { |
| ecc_free(&pubkey); |
| goto LBL_ERR; |
| } |
| ecc_free(&pubkey); |
| y = MAXBLOCKSIZE; |
| if ((err = hash_memory(hash, ecc_shared, x, skey, &y)) != CRYPT_OK) { |
| goto LBL_ERR; |
| } |
| |
| /* Encrypt key */ |
| for (x = 0; x < inlen; x++) { |
| skey[x] ^= in[x]; |
| } |
| |
| err = der_encode_sequence_multi(out, outlen, |
| LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash].OIDlen, hash_descriptor[hash].OID, |
| LTC_ASN1_OCTET_STRING, pubkeysize, pub_expt, |
| LTC_ASN1_OCTET_STRING, inlen, skey, |
| LTC_ASN1_EOL, 0UL, NULL); |
| |
| LBL_ERR: |
| #ifdef LTC_CLEAN_STACK |
| /* clean up */ |
| zeromem(pub_expt, ECC_BUF_SIZE); |
| zeromem(ecc_shared, ECC_BUF_SIZE); |
| zeromem(skey, MAXBLOCKSIZE); |
| #endif |
| |
| XFREE(skey); |
| XFREE(ecc_shared); |
| XFREE(pub_expt); |
| |
| return err; |
| } |
| |
| #endif |
| /* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_encrypt_key.c,v $ */ |
| /* $Revision: 1.4 $ */ |
| /* $Date: 2006/11/21 00:10:18 $ */ |
| |