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263 lines
8.1 KiB
263 lines
8.1 KiB
#define LTC_SOURCE
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*/
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/**
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@file xtea.c
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Implementation of LTC_XTEA, Tom St Denis
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*/
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#include "tomcrypt.h"
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#ifdef LTC_XTEA
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const struct ltc_cipher_descriptor xtea_desc =
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{
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"xtea",
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1,
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16, 16, 8, 32,
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&xtea_setup,
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&xtea_ecb_encrypt,
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&xtea_ecb_decrypt,
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&xtea_test,
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&xtea_done,
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&xtea_keysize,
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NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
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};
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int xtea_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
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{
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ulong32 x, sum, K[4];
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LTC_ARGCHK(key != NULL);
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LTC_ARGCHK(skey != NULL);
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/* check arguments */
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if (keylen != 16) {
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return CRYPT_INVALID_KEYSIZE;
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}
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if (num_rounds != 0 && num_rounds != 32) {
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return CRYPT_INVALID_ROUNDS;
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}
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/* load key */
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LOAD32H(K[0], key+0);
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LOAD32H(K[1], key+4);
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LOAD32H(K[2], key+8);
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LOAD32H(K[3], key+12);
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for (x = sum = 0; x < 32; x++) {
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skey->xtea.A[x] = (sum + K[sum&3]) & 0xFFFFFFFFUL;
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sum = (sum + 0x9E3779B9UL) & 0xFFFFFFFFUL;
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skey->xtea.B[x] = (sum + K[(sum>>11)&3]) & 0xFFFFFFFFUL;
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}
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#ifdef LTC_CLEAN_STACK
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zeromem(&K, sizeof(K));
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#endif
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return CRYPT_OK;
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}
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/**
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Encrypts a block of text with LTC_XTEA
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@param pt The input plaintext (8 bytes)
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@param ct The output ciphertext (8 bytes)
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@param skey The key as scheduled
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@return CRYPT_OK if successful
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*/
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int xtea_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
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{
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ulong32 y, z;
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int r;
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LTC_ARGCHK(pt != NULL);
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LTC_ARGCHK(ct != NULL);
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LTC_ARGCHK(skey != NULL);
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LOAD32H(y, &pt[0]);
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LOAD32H(z, &pt[4]);
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for (r = 0; r < 32; r += 4) {
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y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r])) & 0xFFFFFFFFUL;
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z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r])) & 0xFFFFFFFFUL;
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y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r+1])) & 0xFFFFFFFFUL;
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z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r+1])) & 0xFFFFFFFFUL;
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y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r+2])) & 0xFFFFFFFFUL;
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z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r+2])) & 0xFFFFFFFFUL;
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y = (y + ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r+3])) & 0xFFFFFFFFUL;
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z = (z + ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r+3])) & 0xFFFFFFFFUL;
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}
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STORE32H(y, &ct[0]);
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STORE32H(z, &ct[4]);
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return CRYPT_OK;
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}
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/**
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Decrypts a block of text with LTC_XTEA
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@param ct The input ciphertext (8 bytes)
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@param pt The output plaintext (8 bytes)
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@param skey The key as scheduled
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@return CRYPT_OK if successful
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*/
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int xtea_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
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{
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ulong32 y, z;
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int r;
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LTC_ARGCHK(pt != NULL);
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LTC_ARGCHK(ct != NULL);
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LTC_ARGCHK(skey != NULL);
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LOAD32H(y, &ct[0]);
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LOAD32H(z, &ct[4]);
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for (r = 31; r >= 0; r -= 4) {
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z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r])) & 0xFFFFFFFFUL;
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y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r])) & 0xFFFFFFFFUL;
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z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r-1])) & 0xFFFFFFFFUL;
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y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r-1])) & 0xFFFFFFFFUL;
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z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r-2])) & 0xFFFFFFFFUL;
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y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r-2])) & 0xFFFFFFFFUL;
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z = (z - ((((y<<4)^(y>>5)) + y) ^ skey->xtea.B[r-3])) & 0xFFFFFFFFUL;
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y = (y - ((((z<<4)^(z>>5)) + z) ^ skey->xtea.A[r-3])) & 0xFFFFFFFFUL;
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}
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STORE32H(y, &pt[0]);
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STORE32H(z, &pt[4]);
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return CRYPT_OK;
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}
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/**
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Performs a self-test of the LTC_XTEA block cipher
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@return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
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*/
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int xtea_test(void)
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{
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#ifndef LTC_TEST
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return CRYPT_NOP;
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#else
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static const struct {
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unsigned char key[16], pt[8], ct[8];
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} tests[] = {
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{
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0xde, 0xe9, 0xd4, 0xd8, 0xf7, 0x13, 0x1e, 0xd9 }
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}, {
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{ 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x02,
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0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x04 },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0xa5, 0x97, 0xab, 0x41, 0x76, 0x01, 0x4d, 0x72 }
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}, {
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{ 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x04,
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0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x06 },
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{ 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x02 },
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{ 0xb1, 0xfd, 0x5d, 0xa9, 0xcc, 0x6d, 0xc9, 0xdc }
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}, {
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{ 0x78, 0x69, 0x5a, 0x4b, 0x3c, 0x2d, 0x1e, 0x0f,
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0xf0, 0xe1, 0xd2, 0xc3, 0xb4, 0xa5, 0x96, 0x87 },
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{ 0xf0, 0xe1, 0xd2, 0xc3, 0xb4, 0xa5, 0x96, 0x87 },
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{ 0x70, 0x4b, 0x31, 0x34, 0x47, 0x44, 0xdf, 0xab }
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}, {
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{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
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{ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
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{ 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 }
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}, {
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{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
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{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
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{ 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 }
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}, {
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{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
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{ 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
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{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
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}, {
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
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{ 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 }
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}, {
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
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{ 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d }
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}, {
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 },
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{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
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}
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};
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unsigned char tmp[2][8];
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symmetric_key skey;
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int i, err, y;
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for (i = 0; i < (int)(sizeof(tests)/sizeof(tests[0])); i++) {
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zeromem(&skey, sizeof(skey));
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if ((err = xtea_setup(tests[i].key, 16, 0, &skey)) != CRYPT_OK) {
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return err;
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}
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xtea_ecb_encrypt(tests[i].pt, tmp[0], &skey);
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xtea_ecb_decrypt(tmp[0], tmp[1], &skey);
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if (compare_testvector(tmp[0], 8, tests[i].ct, 8, "XTEA Encrypt", i) != 0 ||
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compare_testvector(tmp[1], 8, tests[i].pt, 8, "XTEA Decrypt", i) != 0) {
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return CRYPT_FAIL_TESTVECTOR;
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}
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/* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
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for (y = 0; y < 8; y++) tmp[0][y] = 0;
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for (y = 0; y < 1000; y++) xtea_ecb_encrypt(tmp[0], tmp[0], &skey);
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for (y = 0; y < 1000; y++) xtea_ecb_decrypt(tmp[0], tmp[0], &skey);
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for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
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} /* for */
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return CRYPT_OK;
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#endif
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}
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/** Terminate the context
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@param skey The scheduled key
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*/
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void xtea_done(symmetric_key *skey)
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{
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LTC_UNUSED_PARAM(skey);
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}
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/**
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Gets suitable key size
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@param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
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@return CRYPT_OK if the input key size is acceptable.
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*/
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int xtea_keysize(int *keysize)
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{
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LTC_ARGCHK(keysize != NULL);
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if (*keysize < 16) {
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return CRYPT_INVALID_KEYSIZE;
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}
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*keysize = 16;
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return CRYPT_OK;
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}
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#endif
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/* ref: $Format:%D$ */
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/* git commit: $Format:%H$ */
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/* commit time: $Format:%ai$ */
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