Mercurial > dropbear
view libtomcrypt/src/pk/pkcs1/pkcs_1_pss_encode.c @ 1659:d32bcb5c557d
Add Ed25519 support (#91)
* Add support for Ed25519 as a public key type
Ed25519 is a elliptic curve signature scheme that offers
better security than ECDSA and DSA and good performance. It may be
used for both user and host keys.
OpenSSH key import and fuzzer are not supported yet.
Initially inspired by Peter Szabo.
* Add curve25519 and ed25519 fuzzers
* Add import and export of Ed25519 keys
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
---|---|
date | Wed, 11 Mar 2020 21:09:45 +0500 |
parents | 6dba84798cd5 |
children |
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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. */ #include "tomcrypt.h" /** @file pkcs_1_pss_encode.c PKCS #1 PSS Signature Padding, Tom St Denis */ #ifdef LTC_PKCS_1 /** PKCS #1 v2.00 Signature Encoding @param msghash The hash to encode @param msghashlen The length of the hash (octets) @param saltlen The length of the salt desired (octets) @param prng An active PRNG context @param prng_idx The index of the PRNG desired @param hash_idx The index of the hash desired @param modulus_bitlen The bit length of the RSA modulus @param out [out] The destination of the encoding @param outlen [in/out] The max size and resulting size of the encoded data @return CRYPT_OK if successful */ int pkcs_1_pss_encode(const unsigned char *msghash, unsigned long msghashlen, unsigned long saltlen, prng_state *prng, int prng_idx, int hash_idx, unsigned long modulus_bitlen, unsigned char *out, unsigned long *outlen) { unsigned char *DB, *mask, *salt, *hash; unsigned long x, y, hLen, modulus_len; int err; hash_state md; LTC_ARGCHK(msghash != NULL); LTC_ARGCHK(out != NULL); LTC_ARGCHK(outlen != NULL); /* ensure hash and PRNG are valid */ if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { return err; } if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) { return err; } hLen = hash_descriptor[hash_idx].hashsize; modulus_bitlen--; modulus_len = (modulus_bitlen>>3) + (modulus_bitlen & 7 ? 1 : 0); /* check sizes */ if ((saltlen > modulus_len) || (modulus_len < hLen + saltlen + 2)) { return CRYPT_PK_INVALID_SIZE; } /* allocate ram for DB/mask/salt/hash of size modulus_len */ DB = XMALLOC(modulus_len); mask = XMALLOC(modulus_len); salt = XMALLOC(modulus_len); hash = XMALLOC(modulus_len); if (DB == NULL || mask == NULL || salt == NULL || hash == NULL) { if (DB != NULL) { XFREE(DB); } if (mask != NULL) { XFREE(mask); } if (salt != NULL) { XFREE(salt); } if (hash != NULL) { XFREE(hash); } return CRYPT_MEM; } /* generate random salt */ if (saltlen > 0) { if (prng_descriptor[prng_idx].read(salt, saltlen, prng) != saltlen) { err = CRYPT_ERROR_READPRNG; goto LBL_ERR; } } /* M = (eight) 0x00 || msghash || salt, hash = H(M) */ if ((err = hash_descriptor[hash_idx].init(&md)) != CRYPT_OK) { goto LBL_ERR; } zeromem(DB, 8); if ((err = hash_descriptor[hash_idx].process(&md, DB, 8)) != CRYPT_OK) { goto LBL_ERR; } if ((err = hash_descriptor[hash_idx].process(&md, msghash, msghashlen)) != CRYPT_OK) { goto LBL_ERR; } if ((err = hash_descriptor[hash_idx].process(&md, salt, saltlen)) != CRYPT_OK) { goto LBL_ERR; } if ((err = hash_descriptor[hash_idx].done(&md, hash)) != CRYPT_OK) { goto LBL_ERR; } /* generate DB = PS || 0x01 || salt, PS == modulus_len - saltlen - hLen - 2 zero bytes */ x = 0; XMEMSET(DB + x, 0, modulus_len - saltlen - hLen - 2); x += modulus_len - saltlen - hLen - 2; DB[x++] = 0x01; XMEMCPY(DB + x, salt, saltlen); /* x += saltlen; */ /* generate mask of length modulus_len - hLen - 1 from hash */ if ((err = pkcs_1_mgf1(hash_idx, hash, hLen, mask, modulus_len - hLen - 1)) != CRYPT_OK) { goto LBL_ERR; } /* xor against DB */ for (y = 0; y < (modulus_len - hLen - 1); y++) { DB[y] ^= mask[y]; } /* output is DB || hash || 0xBC */ if (*outlen < modulus_len) { *outlen = modulus_len; err = CRYPT_BUFFER_OVERFLOW; goto LBL_ERR; } /* DB len = modulus_len - hLen - 1 */ y = 0; XMEMCPY(out + y, DB, modulus_len - hLen - 1); y += modulus_len - hLen - 1; /* hash */ XMEMCPY(out + y, hash, hLen); y += hLen; /* 0xBC */ out[y] = 0xBC; /* now clear the 8*modulus_len - modulus_bitlen most significant bits */ out[0] &= 0xFF >> ((modulus_len<<3) - modulus_bitlen); /* store output size */ *outlen = modulus_len; err = CRYPT_OK; LBL_ERR: #ifdef LTC_CLEAN_STACK zeromem(DB, modulus_len); zeromem(mask, modulus_len); zeromem(salt, modulus_len); zeromem(hash, modulus_len); #endif XFREE(hash); XFREE(salt); XFREE(mask); XFREE(DB); return err; } #endif /* LTC_PKCS_1 */ /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */