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minix/drivers/memory/aes/rijndael_api.c
Philip Homburg 7d4e914618 Random number generator
2005-07-18 15:40:24 +00:00

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/* rijndael-api.c - Rijndael encryption programming interface.
* Author: Kees J. Bot
* 3 Nov 2000
* Heavily based on the original API code by Antoon Bosselaers,
* Vincent Rijmen, and Paulo Barreto, but with a different interface.
*
* Read this code top to bottom, not all comments are repeated.
*/
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include "rijndael-alg.h"
#include "rijndael-api.h"
/* Map a byte (?) address to a word address or vv. */
#define W(a) ((word32 *) (a))
#define B(a) ((word8 *) (a))
#if STRICT_ALIGN
/* This machine checks alignment religiously. (The code is not proper with
* respect to alignment. We need a compiler that doesn't muck about with byte
* arrays that follow words in structs, and that places automatic variables
* at word boundaries if not odd-sized. Most compilers are this nice.)
*/
#define aligned(a) (((unsigned) (a) & 3) == 0)
#define aligned2(a1, a2) aligned((unsigned) (a1) | (unsigned) (a2))
static void blockcpy(void *dst, const void *src)
{
int i= 0;
do {
B(dst)[i+0] = B(src)[i+0];
B(dst)[i+1] = B(src)[i+1];
B(dst)[i+2] = B(src)[i+2];
B(dst)[i+3] = B(src)[i+3];
} while ((i += 4) < 16);
}
#else /* !STRICT_ALIGN */
/* This machine doesn't mind misaligned accesses much. */
#define aligned(a) ((void) (a), 1)
#define aligned2(a1, a2) ((void) (a1), (void) (a2), 1)
#if __GNUC__
__inline
#endif
static void blockcpy(void *dst, const void *src)
{
W(dst)[0] = W(src)[0];
W(dst)[1] = W(src)[1];
W(dst)[2] = W(src)[2];
W(dst)[3] = W(src)[3];
}
#endif /* !STRICT_ALIGN */
#define between(a, c, z) ((unsigned) (c) - (a) <= (unsigned) (z) - (a))
int rijndael_makekey(rd_keyinstance *key,
size_t keylen, const void *keymaterial)
{
word8 k[MAXKC][4];
/* Initialize key schedule: */
if (keylen == RD_KEY_HEX) {
const word8 *kp;
int c, b;
kp= keymaterial;
keylen= 0;
for (;;) {
c= *kp++;
if (between('0', c, '9')) b= (c - '0' + 0x0) << 4;
else
if (between('a', c, 'f')) b= (c - 'a' + 0xa) << 4;
else
if (between('A', c, 'F')) b= (c - 'A' + 0xA) << 4;
else break;
c= *kp++;
if (between('0', c, '9')) b |= (c - '0' + 0x0);
else
if (between('a', c, 'f')) b |= (c - 'a' + 0xa);
else
if (between('A', c, 'F')) b |= (c - 'A' + 0xA);
else break;
if (keylen >= 256/8) return RD_BAD_KEY_MAT;
B(k)[keylen++] = b;
}
if (c != 0) return RD_BAD_KEY_MAT;
if (keylen != 128/8 && keylen != 192/8 && keylen != 256/8) {
return RD_BAD_KEY_MAT;
}
} else {
if (keylen != 128/8 && keylen != 192/8 && keylen != 256/8) {
return RD_BAD_KEY_MAT;
}
memcpy(k, keymaterial, keylen);
}
key->rounds= keylen * 8 / 32 + 6;
rijndael_KeySched(k, key->encsched, key->rounds);
memcpy(key->decsched, key->encsched, sizeof(key->decsched));
rijndael_KeyEncToDec(key->decsched, key->rounds);
return 0;
}
ssize_t rijndael_ecb_encrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *dummyIV)
{
/* Encrypt blocks of data in Electronic Codebook mode. */
const word8 *inp= input;
word8 *outp= output;
size_t i, nr_blocks, extra;
word32 in[4], out[4];
word8 t;
/* Compute the number of whole blocks, and the extra bytes beyond the
* last block. Those extra bytes, if any, are encrypted by stealing
* enough bytes from the previous encrypted block to make a whole block.
* This is done by encrypting the last block, exchanging the first few
* encrypted bytes with the extra bytes, and encrypting the last whole
* block again.
*/
nr_blocks= length / 16;
if ((extra= (length % 16)) > 0) {
if (nr_blocks == 0) return RD_BAD_BLOCK_LENGTH;
nr_blocks--;
}
/* Encrypt a number of blocks. */
if (aligned2(inp, outp)) {
for (i= 0; i < nr_blocks; i++) {
rijndael_Encrypt(inp, outp, key->encsched, key->rounds);
inp += 16;
outp += 16;
}
} else {
for (i= 0; i < nr_blocks; i++) {
blockcpy(in, inp);
rijndael_Encrypt(in, out, key->encsched, key->rounds);
blockcpy(outp, out);
inp += 16;
outp += 16;
}
}
/* Encrypt extra bytes by stealing from the last full block. */
if (extra > 0) {
blockcpy(in, inp);
rijndael_Encrypt(in, out, key->encsched, key->rounds);
for (i= 0; i < extra; i++) {
t= B(out)[i];
B(out)[i] = inp[16 + i];
outp[16 + i] = t;
}
rijndael_Encrypt(out, out, key->encsched, key->rounds);
blockcpy(outp, out);
}
return length;
}
ssize_t rijndael_ecb_decrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *dummyIV)
{
/* Decrypt blocks of data in Electronic Codebook mode. */
const word8 *inp= input;
word8 *outp= output;
size_t i, nr_blocks, extra;
word32 in[4], out[4];
word8 t;
nr_blocks= length / 16;
if ((extra= (length % 16)) > 0) {
if (nr_blocks == 0) return RD_BAD_BLOCK_LENGTH;
nr_blocks--;
}
/* Decrypt a number of blocks. */
if (aligned2(inp, outp)) {
for (i= 0; i < nr_blocks; i++) {
rijndael_Decrypt(inp, outp, key->decsched, key->rounds);
inp += 16;
outp += 16;
}
} else {
for (i= 0; i < nr_blocks; i++) {
blockcpy(in, inp);
rijndael_Decrypt(in, out, key->decsched, key->rounds);
blockcpy(outp, out);
inp += 16;
outp += 16;
}
}
/* Decrypt extra bytes that stole from the last full block. */
if (extra > 0) {
blockcpy(in, inp);
rijndael_Decrypt(in, out, key->decsched, key->rounds);
for (i= 0; i < extra; i++) {
t= B(out)[i];
B(out)[i] = inp[16 + i];
outp[16 + i] = t;
}
rijndael_Decrypt(out, out, key->decsched, key->rounds);
blockcpy(outp, out);
}
return length;
}
ssize_t rijndael_cbc_encrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *IV)
{
/* Encrypt blocks of data in Cypher Block Chaining mode. */
const word8 *inp= input;
word8 *outp= output;
size_t i, nr_blocks, extra;
word32 in[4], out[4], iv[4], *ivp;
word8 t;
nr_blocks= length / 16;
if ((extra= (length % 16)) > 0) {
if (nr_blocks == 0) return RD_BAD_BLOCK_LENGTH;
nr_blocks--;
}
/* Each input block is first XORed with the previous encryption result.
* The "Initialization Vector" is used to XOR the first block with.
* When done the last crypted block is stored back as the new IV to be
* used for another call to this function.
*/
ivp= aligned(IV) ? IV : (blockcpy(iv, IV), iv);
if (aligned2(inp, outp)) {
for (i= 0; i < nr_blocks; i++) {
in[0] = W(inp)[0] ^ ivp[0];
in[1] = W(inp)[1] ^ ivp[1];
in[2] = W(inp)[2] ^ ivp[2];
in[3] = W(inp)[3] ^ ivp[3];
rijndael_Encrypt(in, outp, key->encsched, key->rounds);
ivp= W(outp);
inp += 16;
outp += 16;
}
} else {
for (i= 0; i < nr_blocks; i++) {
blockcpy(in, inp);
in[0] ^= ivp[0];
in[1] ^= ivp[1];
in[2] ^= ivp[2];
in[3] ^= ivp[3];
rijndael_Encrypt(in, out, key->encsched, key->rounds);
blockcpy(outp, out);
ivp= out;
inp += 16;
outp += 16;
}
}
if (extra > 0) {
blockcpy(in, inp);
in[0] ^= ivp[0];
in[1] ^= ivp[1];
in[2] ^= ivp[2];
in[3] ^= ivp[3];
rijndael_Encrypt(in, out, key->encsched, key->rounds);
for (i= 0; i < extra; i++) {
t= B(out)[i];
B(out)[i] ^= inp[16 + i];
outp[16 + i] = t;
}
rijndael_Encrypt(out, out, key->encsched, key->rounds);
blockcpy(outp, out);
ivp= out;
}
blockcpy(IV, ivp); /* Store last IV back. */
return length;
}
ssize_t rijndael_cbc_decrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *IV)
{
/* Decrypt blocks of data in Cypher Block Chaining mode. */
const word8 *inp= input;
word8 *outp= output;
size_t i, nr_blocks, extra;
word32 in[4], out[4], iv[4];
word8 t;
nr_blocks= length / 16;
if ((extra= (length % 16)) > 0) {
if (nr_blocks == 0) return RD_BAD_BLOCK_LENGTH;
nr_blocks--;
}
blockcpy(iv, IV);
if (aligned2(inp, outp)) {
for (i= 0; i < nr_blocks; i++) {
rijndael_Decrypt(inp, out, key->decsched, key->rounds);
out[0] ^= iv[0];
out[1] ^= iv[1];
out[2] ^= iv[2];
out[3] ^= iv[3];
iv[0] = W(inp)[0];
iv[1] = W(inp)[1];
iv[2] = W(inp)[2];
iv[3] = W(inp)[3];
W(outp)[0] = out[0];
W(outp)[1] = out[1];
W(outp)[2] = out[2];
W(outp)[3] = out[3];
inp += 16;
outp += 16;
}
} else {
for (i= 0; i < nr_blocks; i++) {
blockcpy(in, inp);
rijndael_Decrypt(in, out, key->decsched, key->rounds);
out[0] ^= iv[0];
out[1] ^= iv[1];
out[2] ^= iv[2];
out[3] ^= iv[3];
iv[0] = in[0];
iv[1] = in[1];
iv[2] = in[2];
iv[3] = in[3];
blockcpy(outp, out);
inp += 16;
outp += 16;
}
}
if (extra > 0) {
blockcpy(in, inp);
blockcpy(IV, in);
rijndael_Decrypt(in, out, key->decsched, key->rounds);
for (i= 0; i < extra; i++) {
t= B(out)[i] ^ inp[16 + i];
B(out)[i] = inp[16 + i];
outp[16 + i] = t;
}
rijndael_Decrypt(out, out, key->decsched, key->rounds);
out[0] ^= iv[0];
out[1] ^= iv[1];
out[2] ^= iv[2];
out[3] ^= iv[3];
blockcpy(outp, out);
} else {
blockcpy(IV, iv);
}
return length;
}
ssize_t rijndael_cfb1_encrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *IV)
{
/* Encrypt blocks of data in Cypher Feedback mode, 1 bit at a time. */
const word8 *inp= input;
word8 *outp= output;
word8 t;
size_t i;
int b;
word32 iv[4], civ[4];
blockcpy(iv, IV);
for (i= 0; i < length; i++) {
t= *inp++;
for (b= 0; b < 8; b++) {
rijndael_Encrypt(iv, civ, key->encsched, key->rounds);
t ^= (B(civ)[0] & 0x80) >> b;
B(iv)[ 0] = (B(iv)[ 0] << 1) | (B(iv)[ 1] >> 7);
B(iv)[ 1] = (B(iv)[ 1] << 1) | (B(iv)[ 2] >> 7);
B(iv)[ 2] = (B(iv)[ 2] << 1) | (B(iv)[ 3] >> 7);
B(iv)[ 3] = (B(iv)[ 3] << 1) | (B(iv)[ 4] >> 7);
B(iv)[ 4] = (B(iv)[ 4] << 1) | (B(iv)[ 5] >> 7);
B(iv)[ 5] = (B(iv)[ 5] << 1) | (B(iv)[ 6] >> 7);
B(iv)[ 6] = (B(iv)[ 6] << 1) | (B(iv)[ 7] >> 7);
B(iv)[ 7] = (B(iv)[ 7] << 1) | (B(iv)[ 8] >> 7);
B(iv)[ 8] = (B(iv)[ 8] << 1) | (B(iv)[ 9] >> 7);
B(iv)[ 9] = (B(iv)[ 9] << 1) | (B(iv)[10] >> 7);
B(iv)[10] = (B(iv)[10] << 1) | (B(iv)[11] >> 7);
B(iv)[11] = (B(iv)[11] << 1) | (B(iv)[12] >> 7);
B(iv)[12] = (B(iv)[12] << 1) | (B(iv)[13] >> 7);
B(iv)[13] = (B(iv)[13] << 1) | (B(iv)[14] >> 7);
B(iv)[14] = (B(iv)[14] << 1) | (B(iv)[15] >> 7);
B(iv)[15] = (B(iv)[15] << 1) | ((t >> (7-b)) & 1);
}
*outp++ = t;
}
blockcpy(IV, iv);
return length;
}
ssize_t rijndael_cfb1_decrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *IV)
{
/* Decrypt blocks of data in Cypher Feedback mode, 1 bit at a time. */
const word8 *inp= input;
word8 *outp= output;
word8 t;
size_t i;
int b;
word32 iv[4], civ[4];
blockcpy(iv, IV);
for (i= 0; i < length; i++) {
t= *inp++;
for (b= 0; b < 8; b++) {
rijndael_Encrypt(iv, civ, key->encsched, key->rounds);
B(iv)[ 0] = (B(iv)[ 0] << 1) | (B(iv)[ 1] >> 7);
B(iv)[ 1] = (B(iv)[ 1] << 1) | (B(iv)[ 2] >> 7);
B(iv)[ 2] = (B(iv)[ 2] << 1) | (B(iv)[ 3] >> 7);
B(iv)[ 3] = (B(iv)[ 3] << 1) | (B(iv)[ 4] >> 7);
B(iv)[ 4] = (B(iv)[ 4] << 1) | (B(iv)[ 5] >> 7);
B(iv)[ 5] = (B(iv)[ 5] << 1) | (B(iv)[ 6] >> 7);
B(iv)[ 6] = (B(iv)[ 6] << 1) | (B(iv)[ 7] >> 7);
B(iv)[ 7] = (B(iv)[ 7] << 1) | (B(iv)[ 8] >> 7);
B(iv)[ 8] = (B(iv)[ 8] << 1) | (B(iv)[ 9] >> 7);
B(iv)[ 9] = (B(iv)[ 9] << 1) | (B(iv)[10] >> 7);
B(iv)[10] = (B(iv)[10] << 1) | (B(iv)[11] >> 7);
B(iv)[11] = (B(iv)[11] << 1) | (B(iv)[12] >> 7);
B(iv)[12] = (B(iv)[12] << 1) | (B(iv)[13] >> 7);
B(iv)[13] = (B(iv)[13] << 1) | (B(iv)[14] >> 7);
B(iv)[14] = (B(iv)[14] << 1) | (B(iv)[15] >> 7);
B(iv)[15] = (B(iv)[15] << 1) | ((t >> (7-b)) & 1);
t ^= (B(civ)[0] & 0x80) >> b;
}
*outp++ = t;
}
blockcpy(IV, iv);
return length;
}
ssize_t rijndael_cfb8_encrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *IV)
{
/* Encrypt blocks of data in Cypher Feedback mode, 8 bits at a time. */
const word8 *inp= input;
word8 *outp= output;
word8 t;
size_t i;
word32 iv[4], civ[4];
blockcpy(iv, IV);
for (i= 0; i < length; i++) {
t= *inp++;
rijndael_Encrypt(iv, civ, key->encsched, key->rounds);
t ^= B(civ)[0];
B(iv)[ 0] = B(iv)[ 1];
B(iv)[ 1] = B(iv)[ 2];
B(iv)[ 2] = B(iv)[ 3];
B(iv)[ 3] = B(iv)[ 4];
B(iv)[ 4] = B(iv)[ 5];
B(iv)[ 5] = B(iv)[ 6];
B(iv)[ 6] = B(iv)[ 7];
B(iv)[ 7] = B(iv)[ 8];
B(iv)[ 8] = B(iv)[ 9];
B(iv)[ 9] = B(iv)[10];
B(iv)[10] = B(iv)[11];
B(iv)[11] = B(iv)[12];
B(iv)[12] = B(iv)[13];
B(iv)[13] = B(iv)[14];
B(iv)[14] = B(iv)[15];
B(iv)[15] = t;
*outp++ = t;
}
blockcpy(IV, iv);
return length;
}
ssize_t rijndael_cfb8_decrypt(rd_keyinstance *key,
const void *input, void *output, size_t length, void *IV)
{
/* Decrypt blocks of data in Cypher Feedback mode, 1 byte at a time. */
const word8 *inp= input;
word8 *outp= output;
word8 t;
size_t i;
word32 iv[4], civ[4];
blockcpy(iv, IV);
for (i= 0; i < length; i++) {
t= *inp++;
rijndael_Encrypt(iv, civ, key->encsched, key->rounds);
B(iv)[ 0] = B(iv)[ 1];
B(iv)[ 1] = B(iv)[ 2];
B(iv)[ 2] = B(iv)[ 3];
B(iv)[ 3] = B(iv)[ 4];
B(iv)[ 4] = B(iv)[ 5];
B(iv)[ 5] = B(iv)[ 6];
B(iv)[ 6] = B(iv)[ 7];
B(iv)[ 7] = B(iv)[ 8];
B(iv)[ 8] = B(iv)[ 9];
B(iv)[ 9] = B(iv)[10];
B(iv)[10] = B(iv)[11];
B(iv)[11] = B(iv)[12];
B(iv)[12] = B(iv)[13];
B(iv)[13] = B(iv)[14];
B(iv)[14] = B(iv)[15];
B(iv)[15] = t;
t ^= B(civ)[0];
*outp++ = t;
}
blockcpy(IV, iv);
return length;
}
ssize_t rijndael_pad(void *input, size_t length)
{
/* Adds at most one block of RFC-2040 style padding to the input to make
* it a whole number of blocks for easier encryption. To be used if the
* input may be less then one block in size, otherwise let the encryption
* routines use cypher stealing. The input buffer should allow enough
* space for the padding. The new length of the input is returned.
*/
word8 *inp= input;
size_t padlen;
/* Add padding up until the next block boundary. */
padlen= 16 - (length % 16);
memset(inp + length, padlen, padlen);
return length + padlen;
}
ssize_t rijndael_unpad(const void *input, size_t length)
{
/* Remove RFC-2040 style padding after decryption. The true length of
* the input is returned, or the usual errors if the padding is incorrect.
*/
const word8 *inp= input;
size_t i, padlen;
if (length == 0 || (length % 16) != 0) return RD_BAD_BLOCK_LENGTH;
padlen = inp[length-1];
if (padlen <= 0 || padlen > 16) return RD_BAD_DATA;
for (i= 2; i <= padlen; i++) {
if (inp[length-i] != padlen) return RD_BAD_DATA;
}
return length - padlen;
}
#ifdef INTERMEDIATE_VALUE_KAT
void cipherEncryptUpdateRounds(rd_keyinstance *key,
const void *input, void *output, int rounds)
{
/* Encrypt a block only a specified number of rounds. */
word8 block[4][4];
blockcpy(block, input);
rijndaelEncryptRound(block, key->encsched, key->rounds, rounds);
blockcpy(output, block);
}
void cipherDecryptUpdateRounds(rd_keyinstance *key,
const void *input, void *output, int rounds)
{
/* Decrypt a block only a specified number of rounds. */
word8 block[4][4];
blockcpy(block, input);
rijndaelDecryptRound(block, key->decsched, key->rounds, rounds);
blockcpy(output, block);
}
#endif /* INTERMEDIATE_VALUE_KAT */
/*
* $PchId: rijndael_api.c,v 1.2 2001/01/10 22:01:20 philip Exp $
*/
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