Mercurial > dropbear
view libtomcrypt/src/ciphers/xtea.c @ 797:45f1bc96f357 ecc
Fix build for dropbearkey and ecdsa with certain options
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 09 May 2013 23:24:58 +0800 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
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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 */ /** @file xtea.c Implementation of XTEA, Tom St Denis */ #include "tomcrypt.h" #ifdef XTEA const struct ltc_cipher_descriptor xtea_desc = { "xtea", 1, 16, 16, 8, 32, &xtea_setup, &xtea_ecb_encrypt, &xtea_ecb_decrypt, &xtea_test, &xtea_done, &xtea_keysize, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; int xtea_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) { unsigned long x, sum, K[4]; LTC_ARGCHK(key != NULL); LTC_ARGCHK(skey != NULL); /* check arguments */ if (keylen != 16) { return CRYPT_INVALID_KEYSIZE; } if (num_rounds != 0 && num_rounds != 32) { return CRYPT_INVALID_ROUNDS; } /* load key */ LOAD32L(K[0], key+0); LOAD32L(K[1], key+4); LOAD32L(K[2], key+8); LOAD32L(K[3], key+12); for (x = sum = 0; x < 32; x++) { skey->xtea.A[x] = (sum + K[sum&3]) & 0xFFFFFFFFUL; sum = (sum + 0x9E3779B9UL) & 0xFFFFFFFFUL; skey->xtea.B[x] = (sum + K[(sum>>11)&3]) & 0xFFFFFFFFUL; } #ifdef LTC_CLEAN_STACK zeromem(&K, sizeof(K)); #endif return CRYPT_OK; } /** Encrypts a block of text with XTEA @param pt The input plaintext (8 bytes) @param ct The output ciphertext (8 bytes) @param skey The key as scheduled @return CRYPT_OK if successful */ int xtea_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) { unsigned long y, z; int r; LTC_ARGCHK(pt != NULL); LTC_ARGCHK(ct != NULL); LTC_ARGCHK(skey != NULL); LOAD32L(y, &pt[0]); LOAD32L(z, &pt[4]); for (r = 0; r < 32; r += 4) { y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r])) & 0xFFFFFFFFUL; z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r])) & 0xFFFFFFFFUL; y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r+1])) & 0xFFFFFFFFUL; z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r+1])) & 0xFFFFFFFFUL; y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r+2])) & 0xFFFFFFFFUL; z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r+2])) & 0xFFFFFFFFUL; y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r+3])) & 0xFFFFFFFFUL; z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r+3])) & 0xFFFFFFFFUL; } STORE32L(y, &ct[0]); STORE32L(z, &ct[4]); return CRYPT_OK; } /** Decrypts a block of text with XTEA @param ct The input ciphertext (8 bytes) @param pt The output plaintext (8 bytes) @param skey The key as scheduled @return CRYPT_OK if successful */ int xtea_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) { unsigned long y, z; int r; LTC_ARGCHK(pt != NULL); LTC_ARGCHK(ct != NULL); LTC_ARGCHK(skey != NULL); LOAD32L(y, &ct[0]); LOAD32L(z, &ct[4]); for (r = 31; r >= 0; r -= 4) { z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r])) & 0xFFFFFFFFUL; y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r])) & 0xFFFFFFFFUL; z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r-1])) & 0xFFFFFFFFUL; y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r-1])) & 0xFFFFFFFFUL; z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r-2])) & 0xFFFFFFFFUL; y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r-2])) & 0xFFFFFFFFUL; z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r-3])) & 0xFFFFFFFFUL; y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r-3])) & 0xFFFFFFFFUL; } STORE32L(y, &pt[0]); STORE32L(z, &pt[4]); return CRYPT_OK; } /** Performs a self-test of the XTEA block cipher @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled */ int xtea_test(void) { #ifndef LTC_TEST return CRYPT_NOP; #else static const unsigned char key[16] = { 0x78, 0x56, 0x34, 0x12, 0xf0, 0xcd, 0xcb, 0x9a, 0x48, 0x37, 0x26, 0x15, 0xc0, 0xbf, 0xae, 0x9d }; static const unsigned char pt[8] = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 }; static const unsigned char ct[8] = { 0x75, 0xd7, 0xc5, 0xbf, 0xcf, 0x58, 0xc9, 0x3f }; unsigned char tmp[2][8]; symmetric_key skey; int err, y; if ((err = xtea_setup(key, 16, 0, &skey)) != CRYPT_OK) { return err; } xtea_ecb_encrypt(pt, tmp[0], &skey); xtea_ecb_decrypt(tmp[0], tmp[1], &skey); if (XMEMCMP(tmp[0], ct, 8) != 0 || XMEMCMP(tmp[1], pt, 8) != 0) { return CRYPT_FAIL_TESTVECTOR; } /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */ for (y = 0; y < 8; y++) tmp[0][y] = 0; for (y = 0; y < 1000; y++) xtea_ecb_encrypt(tmp[0], tmp[0], &skey); for (y = 0; y < 1000; y++) xtea_ecb_decrypt(tmp[0], tmp[0], &skey); for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; return CRYPT_OK; #endif } /** Terminate the context @param skey The scheduled key */ void xtea_done(symmetric_key *skey) { } /** Gets suitable key size @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable. @return CRYPT_OK if the input key size is acceptable. */ int xtea_keysize(int *keysize) { LTC_ARGCHK(keysize != NULL); if (*keysize < 16) { return CRYPT_INVALID_KEYSIZE; } *keysize = 16; return CRYPT_OK; } #endif /* $Source: /cvs/libtom/libtomcrypt/src/ciphers/xtea.c,v $ */ /* $Revision: 1.12 $ */ /* $Date: 2006/11/08 23:01:06 $ */