Mercurial > dropbear
view src/pk/ecc/ecc_encrypt_key.c @ 380:d5faf4814ddb libtomcrypt-orig libtomcrypt-1.16
Update to LibTomCrypt 1.16
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 11 Jan 2007 02:22:00 +0000 |
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/* 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, [email protected], 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 $ */