Mercurial > dropbear
view libtomcrypt/src/pk/katja/katja_decrypt_key.c @ 1693:f9ad4d39e388
Bring back -Werror and improve travis tests
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 26 May 2020 23:53:50 +0800 |
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 katja_decrypt_key.c Katja PKCS #1 OAEP Decryption, Tom St Denis */ #ifdef LTC_MKAT /** (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 Katja key @return CRYPT_OK if succcessul (even if invalid) */ int katja_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, katja_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)); /* payload is upto pq, so we know q is 1/3rd the size of N and therefore pq is 2/3th the size */ modulus_bitlen = ((modulus_bitlen << 1) / 3); /* round down to next byte */ modulus_bitlen -= (modulus_bitlen & 7) + 8; /* 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 = katja_exptmod(in, inlen, tmp, &x, PK_PRIVATE, key)) != CRYPT_OK) { XFREE(tmp); return err; } /* shift right by modulus_bytelen - modulus_bitlen/8 bytes */ for (x = 0; x < (modulus_bitlen >> 3); x++) { tmp[x] = tmp[x+(modulus_bytelen-(modulus_bitlen>>3))]; } /* 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 /* LTC_MRSA */ /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */