65816-crypto/aesmodes.c
2024-06-26 20:46:58 -06:00

409 lines
8.9 KiB
C

/*
* Copyright (c) 2017 Stephen Heumann
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#pragma noroot
#pragma lint -1
#pragma optimize -1
#include <string.h>
#include "aes.h"
extern void AES_ENCRYPT(void);
extern void AES_DECRYPT(void);
/*
* Encrypt data using AES-128, AES-192, or AES-256 in CBC mode.
* The key must have been specified via aes{128,192,256}_expandkey().
* The initialization vector (IV) must be in context->data.
* nblocks gives the number of 16-byte blocks to be processed.
*/
void aes_cbc_encrypt(struct aes_context *context,
const unsigned char *in,
unsigned char *out,
unsigned long nblocks)
{
while (nblocks-- > 0) {
asm {
lda [in]
eor [context]
sta [context]
ldy #2
lda [in],y
eor [context],y
sta [context],y
iny
iny
lda [in],y
eor [context],y
sta [context],y
iny
iny
lda [in],y
eor [context],y
sta [context],y
iny
iny
lda [in],y
eor [context],y
sta [context],y
iny
iny
lda [in],y
eor [context],y
sta [context],y
iny
iny
lda [in],y
eor [context],y
sta [context],y
iny
iny
lda [in],y
eor [context],y
sta [context],y
phd
lda context
tcd
jsl AES_ENCRYPT
lda 0
pld
sta [out]
ldy #2
lda [context],y
sta [out],y
iny
iny
lda [context],y
sta [out],y
iny
iny
lda [context],y
sta [out],y
iny
iny
lda [context],y
sta [out],y
iny
iny
lda [context],y
sta [out],y
iny
iny
lda [context],y
sta [out],y
iny
iny
lda [context],y
sta [out],y
}
in += 16;
out += 16;
}
}
/*
* Decrypt data using AES-128, AES-192, or AES-256 in CBC mode.
* The key must have been specified via aes{128,192,256}_expandkey().
* nblocks gives the number of 16-byte blocks to be processed.
*/
void aes_cbc_decrypt(struct aes_context *context,
const unsigned char *in,
unsigned char *out,
unsigned long nblocks,
const unsigned char *iv)
{
if (nblocks-- == 0)
return;
asm {
lda [in]
sta [context]
ldy #2
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
phd
lda context
tcd
jsl AES_DECRYPT
pld
ldy #0
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
iny
iny
lda [context],y
eor [iv],y
sta [out],y
}
in += 16;
out += 16;
while (nblocks-- > 0) {
asm {
lda [in]
sta [context]
ldy #2
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
iny
iny
lda [in],y
sta [context],y
phd
lda context
tcd
jsl AES_DECRYPT
pld
}
in -= 16;
asm {
ldy #0
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
}
in += 32;
out += 16;
}
}
/*
* Process data using AES-128, AES-192, or AES-256 in CTR mode.
* This either encrypts or decrypts data, depending on whether
* in contains plaintext or ciphertext.
* The key must have been specified via aes{128,192,256}_expandkey().
* nblocks gives the number of 16-byte blocks to be processed.
* counter will be interpreted as a 128-bit big-endian integer,
* and incremented for each block processed.
*/
void aes_ctr_process(struct aes_context *context,
const unsigned char *in,
unsigned char *out,
unsigned long nblocks,
const unsigned char *counter)
{
while (nblocks-- > 0) {
asm {
lda [counter]
sta [context]
ldy #2
lda [counter],y
sta [context],y
iny
iny
lda [counter],y
sta [context],y
iny
iny
lda [counter],y
sta [context],y
iny
iny
lda [counter],y
sta [context],y
iny
iny
lda [counter],y
sta [context],y
iny
iny
lda [counter],y
sta [context],y
iny
iny
lda [counter],y
sta [context],y
phd
lda context
tcd
jsl AES_ENCRYPT
pld
lda [context]
eor [in]
sta [out]
ldy #2
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
iny
iny
lda [context],y
eor [in],y
sta [out],y
ldy #14
incloop: lda [counter],y
xba
inc a
xba
sta [counter],y
bne incdone
dey
dey
bpl incloop
incdone:
}
in += 16;
out += 16;
}
}