#ifndef AES_H
#define AES_H
/* aes.h */
/* ---------- See examples at end of this file for typical usage -------- */
/* AES Cipher header file for ANSI C Submissions
Lawrence E. Bassham III
Computer Security Division
National Institute of Standards and Technology
This sample is to assist implementers developing to the
Cryptographic API Profile for AES Candidate Algorithm Submissions.
Please consult this document as a cross-reference.
ANY CHANGES, WHERE APPROPRIATE, TO INFORMATION PROVIDED IN THIS FILE
MUST BE DOCUMENTED. CHANGES ARE ONLY APPROPRIATE WHERE SPECIFIED WITH
THE STRING "CHANGE POSSIBLE". FUNCTION CALLS AND THEIR PARAMETERS
CANNOT BE CHANGED. STRUCTURES CAN BE ALTERED TO ALLOW IMPLEMENTERS TO
INCLUDE IMPLEMENTATION SPECIFIC INFORMATION.
*/
/* Includes:
Standard include files
*/
#include <stdio.h>
#include "platform.h" /* platform-specific defines */
/* Defines:
Add any additional defines you need
*/
#define DIR_ENCRYPT 0 /* Are we encrpyting? */
#define DIR_DECRYPT 1 /* Are we decrpyting? */
#define MODE_ECB 1 /* Are we ciphering in ECB mode? */
#define MODE_CBC 2 /* Are we ciphering in CBC mode? */
#define MODE_CFB1 3 /* Are we ciphering in 1-bit CFB mode? */
#define BAD_KEY_DIR -5 /* Key direction is invalid (unknown value) */
#define BAD_KEY_MAT -6 /* Key material not of correct length */
#define BAD_KEY_INSTANCE -7 /* Key passed is not valid */
#define BAD_CIPHER_MODE -8 /* Params struct passed to cipherInit invalid */
#define BAD_CIPHER_STATE -9 /* Cipher in wrong state (e.g., not initialized) */
/* CHANGE POSSIBLE: inclusion of algorithm specific defines */
/* TWOFISH specific definitions */
#define MAX_KEY_SIZE 64 /* # of ASCII chars needed to represent a key */
#define MAX_IV_SIZE 16 /* # of bytes needed to represent an IV */
#define BAD_INPUT_LEN -6 /* inputLen not a multiple of block size */
#define BAD_PARAMS -7 /* invalid parameters */
#define BAD_IV_MAT -8 /* invalid IV text */
#define BAD_ENDIAN -9 /* incorrect endianness define */
#define BAD_ALIGN32 -10 /* incorrect 32-bit alignment */
#define BLOCK_SIZE 128 /* number of bits per block */
#define MAX_ROUNDS 16 /* max # rounds (for allocating subkey array) */
#define ROUNDS_128 16 /* default number of rounds for 128-bit keys*/
#define ROUNDS_192 16 /* default number of rounds for 192-bit keys*/
#define ROUNDS_256 16 /* default number of rounds for 256-bit keys*/
#define MAX_KEY_BITS 256 /* max number of bits of key */
#define MIN_KEY_BITS 128 /* min number of bits of key (zero pad) */
#define VALID_SIG 0x48534946 /* initialization signature ('FISH') */
#define MCT_OUTER 400 /* MCT outer loop */
#define MCT_INNER 10000 /* MCT inner loop */
#define REENTRANT 1 /* nonzero forces reentrant code (slightly slower) */
#define INPUT_WHITEN 0 /* subkey array indices */
#define OUTPUT_WHITEN ( INPUT_WHITEN + BLOCK_SIZE/32)
#define ROUND_SUBKEYS (OUTPUT_WHITEN + BLOCK_SIZE/32) /* use 2 * (# rounds) */
#define TOTAL_SUBKEYS (ROUND_SUBKEYS + 2*MAX_ROUNDS)
/* Typedefs:
Typedef'ed data storage elements. Add any algorithm specific
parameters at the bottom of the structs as appropriate.
*/
typedef DWORD fullSbox[4][256];
/* The structure for key information */
typedef struct
{
BYTE direction; /* Key used for encrypting or decrypting? */
#if ALIGN32
BYTE dummyAlign[3]; /* keep 32-bit alignment */
#endif
int keyLen; /* Length of the key */
/* Twofish-specific parameters: */
DWORD keySig; /* set to VALID_SIG by makeKey() */
int numRounds; /* number of rounds in cipher */
DWORD key32[MAX_KEY_BITS/32]; /* actual key bits, in dwords */
DWORD sboxKeys[MAX_KEY_BITS/64];/* key bits used for S-boxes */
DWORD subKeys[TOTAL_SUBKEYS]; /* round subkeys, input/output whitening bits */
#if REENTRANT
fullSbox sBox8x32; /* fully expanded S-box */
#if defined(COMPILE_KEY) && defined(USE_ASM)
#undef VALID_SIG
#define VALID_SIG 0x504D4F43 /* 'COMP': C is compiled with -DCOMPILE_KEY */
DWORD cSig1; /* set after first "compile" (zero at "init") */
void *encryptFuncPtr; /* ptr to asm encrypt function */
void *decryptFuncPtr; /* ptr to asm decrypt function */
DWORD codeSize; /* size of compiledCode */
DWORD cSig2; /* set after first "compile" */
BYTE compiledCode[5000]; /* make room for the code itself */
#endif
#endif
} keyInstance;
/* The structure for cipher information */
typedef struct
{
BYTE mode; /* MODE_ECB, MODE_CBC, or MODE_CFB1 */
#if ALIGN32
BYTE dummyAlign[3]; /* keep 32-bit alignment */
#endif
BYTE IV[MAX_IV_SIZE]; /* CFB1 iv bytes (CBC uses iv32) */
/* Twofish-specific parameters: */
DWORD cipherSig; /* set to VALID_SIG by cipherInit() */
DWORD iv32[BLOCK_SIZE/32]; /* CBC IV bytes arranged as dwords */
} cipherInstance;
/* Function protoypes */
static int makeKey(keyInstance *key, BYTE direction, int keyLen, char *keyMaterial);
static int cipherInit(cipherInstance *cipher, BYTE mode, char *IV);
static int blockEncrypt(cipherInstance *cipher, keyInstance *key, BYTE *input,
int inputLen, BYTE *outBuffer);
static int blockDecrypt(cipherInstance *cipher, keyInstance *key, BYTE *input,
int inputLen, BYTE *outBuffer);
static int reKey(keyInstance *key); /* do key schedule using modified key.keyDwords */
/* API to check table usage, for use in ECB_TBL KAT */
#define TAB_DISABLE 0
#define TAB_ENABLE 1
#define TAB_RESET 2
#define TAB_QUERY 3
#define TAB_MIN_QUERY 50
static int TableOp(int op);
#define CONST /* helpful C++ syntax sugar, NOP for ANSI C */
#if BLOCK_SIZE == 128 /* optimize block copies */
#define Copy1(d,s,N) ((DWORD *)(d))[N] = ((DWORD *)(s))[N]
#define BlockCopy(d,s) { Copy1(d,s,0);Copy1(d,s,1);Copy1(d,s,2);Copy1(d,s,3); }
#else
#define BlockCopy(d,s) { memcpy(d,s,BLOCK_SIZE/8); }
#endif
#ifdef TEST_2FISH
/* ----- EXAMPLES -----
Unfortunately, the AES API is somewhat clumsy, and it is not entirely
obvious how to use the above functions. In particular, note that
makeKey() takes an ASCII hex nibble key string (e.g., 32 characters
for a 128-bit key), which is rarely the way that keys are internally
represented. The reKey() function uses instead the keyInstance.key32
array of key bits and is the preferred method. In fact, makeKey()
initializes some internal keyInstance state, then parse the ASCII
string into the binary key32, and calls reKey(). To initialize the
keyInstance state, use a 'dummy' call to makeKey(); i.e., set the
keyMaterial parameter to NULL. Then use reKey() for all key changes.
Similarly, cipherInit takes an IV string in ASCII hex, so a dummy setup
call with a null IV string will skip the ASCII parse.
Note that CFB mode is not well tested nor defined by AES, so using the
Twofish MODE_CFB it not recommended. If you wish to implement a CFB mode,
build it external to the Twofish code, using the Twofish functions only
in ECB mode.
Below is a sample piece of code showing how the code is typically used
to set up a key, encrypt, and decrypt. Error checking is somewhat limited
in this example. Pseudorandom bytes are used for all key and text.
If you compile TWOFISH2.C or TWOFISH.C as a DOS (or Windows Console) app
with this code enabled, the test will be run. For example, using
Borland C, you would compile using:
BCC32 -DTEST_2FISH twofish2.c
to run the test on the optimized code, or
BCC32 -DTEST_2FISH twofish.c
to run the test on the pedagogical code.
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define MAX_BLK_CNT 4 /* max # blocks per call in TestTwofish */
static int TestTwofish(int mode,int keySize) /* keySize must be 128, 192, or 256 */
{ /* return 0 iff test passes */
keyInstance ki; /* key information, including tables */
cipherInstance ci; /* keeps mode (ECB, CBC) and IV */
BYTE plainText[MAX_BLK_CNT*(BLOCK_SIZE/8)];
BYTE cipherText[MAX_BLK_CNT*(BLOCK_SIZE/8)];
BYTE decryptOut[MAX_BLK_CNT*(BLOCK_SIZE/8)];
BYTE iv[BLOCK_SIZE/8];
int i,byteCnt;
if (makeKey(&ki,DIR_ENCRYPT,keySize,NULL) != TRUE)
return 1; /* 'dummy' setup for a 128-bit key */
if (cipherInit(&ci,mode,NULL) != TRUE)
return 1; /* 'dummy' setup for cipher */
for (i=0;i<keySize/32;i++) /* select key bits */
ki.key32[i]=0x10003 * rand();
reKey(&ki); /* run the key schedule */
if (mode != MODE_ECB) /* set up random iv (if needed)*/
{
for (i=0;i<sizeof(iv);i++)
iv[i]=(BYTE) rand();
memcpy(ci.iv32,iv,sizeof(ci.iv32)); /* copy the IV to ci */
}
/* select number of bytes to encrypt (multiple of block) */
/* e.g., byteCnt = 16, 32, 48, 64 */
byteCnt = (BLOCK_SIZE/8) * (1 + (rand() % MAX_BLK_CNT));
for (i=0;i<byteCnt;i++) /* generate test data */
plainText[i]=(BYTE) rand();
/* encrypt the bytes */
if (blockEncrypt(&ci,&ki, plainText,byteCnt*8,cipherText) != byteCnt*8)
return 1;
/* decrypt the bytes */
if (mode != MODE_ECB) /* first re-init the IV (if needed) */
memcpy(ci.iv32,iv,sizeof(ci.iv32));
if (blockDecrypt(&ci,&ki,cipherText,byteCnt*8,decryptOut) != byteCnt*8)
return 1;
/* make sure the decrypt output matches original plaintext */
if (memcmp(plainText,decryptOut,byteCnt))
return 1;
return 0; /* tests passed! */
}
void main(void)
{
int testCnt,keySize;
srand((unsigned) time(NULL)); /* randomize */
for (keySize=128;keySize<=256;keySize+=64)
for (testCnt=0;testCnt<10;testCnt++)
{
if (TestTwofish(MODE_ECB,keySize))
{ printf("ECB Failure at keySize=%d",keySize); return; }
if (TestTwofish(MODE_CBC,keySize))
{ printf("CBC Failure at keySize=%d",keySize); return; }
}
printf("Tests passed");
}
#endif /* TEST_2FISH */
#endif