Mercurial > dropbear
view src/pk/rsa/rsa_decrypt_key.c @ 222:36160290a1b2 libtomcrypt LTC_DB_0.46
* change include path of options.h
* don't use the constant ROL/ROR operations, since compilers
seem to have problems
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Fri, 08 Jul 2005 19:13:24 +0000 |
parents | 39d5d58461d6 |
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. * * Tom St Denis, [email protected], http://libtomcrypt.org */ #include "tomcrypt.h" /** @file rsa_decrypt_key.c RSA PKCS #1 OAEP Decryption, Tom St Denis */ #ifdef MRSA /** (PKCS #1 v2.0) decrypt then OAEP depad @param in The ciphertext @param inlen The length of the ciphertext (octets) @param out [out] The plaintext @param outlen [in/out] The max size and resulting size of the plaintext (octets) @param lparam The system "lparam" value @param lparamlen The length of the lparam value (octets) @param hash_idx The index of the hash desired @param stat [out] Result of the decryption, 1==valid, 0==invalid @param key The corresponding private RSA key @return CRYPT_OK if succcessul (even if invalid) */ int rsa_decrypt_key(const unsigned char *in, unsigned long inlen, unsigned char *out, unsigned long *outlen, const unsigned char *lparam, unsigned long lparamlen, int hash_idx, int *stat, rsa_key *key) { unsigned long modulus_bitlen, modulus_bytelen, x; int err; unsigned char *tmp; LTC_ARGCHK(out != NULL); LTC_ARGCHK(outlen != NULL); LTC_ARGCHK(key != NULL); LTC_ARGCHK(stat != NULL); /* default to invalid */ *stat = 0; /* valid hash ? */ if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { return err; } /* get modulus len in bits */ modulus_bitlen = mp_count_bits(&(key->N)); /* outlen must be at least the size of the modulus */ modulus_bytelen = mp_unsigned_bin_size(&(key->N)); if (modulus_bytelen != inlen) { return CRYPT_INVALID_PACKET; } /* allocate ram */ tmp = XMALLOC(inlen); if (tmp == NULL) { return CRYPT_MEM; } /* rsa decode the packet */ x = inlen; if ((err = rsa_exptmod(in, inlen, tmp, &x, PK_PRIVATE, key)) != CRYPT_OK) { XFREE(tmp); return err; } /* now OAEP decode the packet */ err = pkcs_1_oaep_decode(tmp, x, lparam, lparamlen, modulus_bitlen, hash_idx, out, outlen, stat); XFREE(tmp); return err; } #endif /* MRSA */ /* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_decrypt_key.c,v $ */ /* $Revision: 1.3 $ */ /* $Date: 2005/05/05 14:35:59 $ */