libtomcrypt/src/ciphers/rc5.c - platform/external/dropbear - Git at Google

 /* 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 rc5.c
    RC5 code by Tom St Denis
 */

 #include "tomcrypt.h"

 #ifdef RC5

 const struct ltc_cipher_descriptor rc5_desc =
 {
     "rc5",
     2,
     8, 128, 8, 12,
     &rc5_setup,
     &rc5_ecb_encrypt,
     &rc5_ecb_decrypt,
     &rc5_test,
     &rc5_done,
     &rc5_keysize,
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
 };

 static const ulong32 stab[50] = {
 0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL,
 0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL,
 0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL,
 0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL,
 0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL,
 0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL, 0xe96a3d2fUL, 0x87a1b6e8UL, 0x25d930a1UL, 0xc410aa5aUL,
 0x62482413UL, 0x007f9dccUL
 };

  /**
     Initialize the RC5 block cipher
     @param key The symmetric key you wish to pass
     @param keylen The key length in bytes
     @param num_rounds The number of rounds desired (0 for default)
     @param skey The key in as scheduled by this function.
     @return CRYPT_OK if successful
  */
 #ifdef LTC_CLEAN_STACK
 static int _rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
 #else
 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
 #endif
 {
     ulong32 L[64], *S, A, B, i, j, v, s, t, l;

     LTC_ARGCHK(skey != NULL);
     LTC_ARGCHK(key  != NULL);

     /* test parameters */
     if (num_rounds == 0) {
        num_rounds = rc5_desc.default_rounds;
     }

     if (num_rounds < 12 || num_rounds > 24) {
        return CRYPT_INVALID_ROUNDS;
     }

     /* key must be between 64 and 1024 bits */
     if (keylen < 8 || keylen > 128) {
        return CRYPT_INVALID_KEYSIZE;
     }

     skey->rc5.rounds = num_rounds;
     S = skey->rc5.K;

     /* copy the key into the L array */
     for (A = i = j = 0; i < (ulong32)keylen; ) {
         A = (A << 8) | ((ulong32)(key[i++] & 255));
         if ((i & 3) == 0) {
            L[j++] = BSWAP(A);
            A = 0;
         }
     }

     if ((keylen & 3) != 0) {
        A <<= (ulong32)((8 * (4 - (keylen&3))));
        L[j++] = BSWAP(A);
     }

     /* setup the S array */
     t = (ulong32)(2 * (num_rounds + 1));
     XMEMCPY(S, stab, t * sizeof(*S));

     /* mix buffer */
     s = 3 * MAX(t, j);
     l = j;
     for (A = B = i = j = v = 0; v < s; v++) {
         A = S[i] = ROLc(S[i] + A + B, 3);
         B = L[j] = ROL(L[j] + A + B, (A+B));
         if (++i == t) { i = 0; }
         if (++j == l) { j = 0; }
     }
     return CRYPT_OK;
 }

 #ifdef LTC_CLEAN_STACK
 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
 {
    int x;
    x = _rc5_setup(key, keylen, num_rounds, skey);
    burn_stack(sizeof(ulong32) * 122 + sizeof(int));
    return x;
 }
 #endif

 /**
   Encrypts a block of text with RC5
   @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
 */
 #ifdef LTC_CLEAN_STACK
 static int _rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
 #else
 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
 #endif
 {
    ulong32 A, B, *K;
    int r;
    LTC_ARGCHK(skey != NULL);
    LTC_ARGCHK(pt   != NULL);
    LTC_ARGCHK(ct   != NULL);

    LOAD32L(A, &pt[0]);
    LOAD32L(B, &pt[4]);
    A += skey->rc5.K[0];
    B += skey->rc5.K[1];
    K  = skey->rc5.K + 2;

    if ((skey->rc5.rounds & 1) == 0) {
       for (r = 0; r < skey->rc5.rounds; r += 2) {
           A = ROL(A ^ B, B) + K[0];
           B = ROL(B ^ A, A) + K[1];
           A = ROL(A ^ B, B) + K[2];
           B = ROL(B ^ A, A) + K[3];
           K += 4;
       }
    } else {
       for (r = 0; r < skey->rc5.rounds; r++) {
           A = ROL(A ^ B, B) + K[0];
           B = ROL(B ^ A, A) + K[1];
           K += 2;
       }
    }
    STORE32L(A, &ct[0]);
    STORE32L(B, &ct[4]);

    return CRYPT_OK;
 }

 #ifdef LTC_CLEAN_STACK
 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
 {
    int err = _rc5_ecb_encrypt(pt, ct, skey);
    burn_stack(sizeof(ulong32) * 2 + sizeof(int));
    return err;
 }
 #endif

 /**
   Decrypts a block of text with RC5
   @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
 */
 #ifdef LTC_CLEAN_STACK
 static int _rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
 #else
 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
 #endif
 {
    ulong32 A, B, *K;
    int r;
    LTC_ARGCHK(skey != NULL);
    LTC_ARGCHK(pt   != NULL);
    LTC_ARGCHK(ct   != NULL);

    LOAD32L(A, &ct[0]);
    LOAD32L(B, &ct[4]);
    K = skey->rc5.K + (skey->rc5.rounds << 1);

    if ((skey->rc5.rounds & 1) == 0) {
        K -= 2;
        for (r = skey->rc5.rounds - 1; r >= 0; r -= 2) {
           B = ROR(B - K[3], A) ^ A;
           A = ROR(A - K[2], B) ^ B;
           B = ROR(B - K[1], A) ^ A;
           A = ROR(A - K[0], B) ^ B;
           K -= 4;
         }
    } else {
       for (r = skey->rc5.rounds - 1; r >= 0; r--) {
           B = ROR(B - K[1], A) ^ A;
           A = ROR(A - K[0], B) ^ B;
           K -= 2;
       }
    }
    A -= skey->rc5.K[0];
    B -= skey->rc5.K[1];
    STORE32L(A, &pt[0]);
    STORE32L(B, &pt[4]);

    return CRYPT_OK;
 }

 #ifdef LTC_CLEAN_STACK
 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
 {
    int err = _rc5_ecb_decrypt(ct, pt, skey);
    burn_stack(sizeof(ulong32) * 2 + sizeof(int));
    return err;
 }
 #endif

 /**
   Performs a self-test of the RC5 block cipher
   @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
 */
 int rc5_test(void)
 {
  #ifndef LTC_TEST
     return CRYPT_NOP;
  #else
    static const struct {
        unsigned char key[16], pt[8], ct[8];
    } tests[] = {
    {
        { 0x91, 0x5f, 0x46, 0x19, 0xbe, 0x41, 0xb2, 0x51,
          0x63, 0x55, 0xa5, 0x01, 0x10, 0xa9, 0xce, 0x91 },
        { 0x21, 0xa5, 0xdb, 0xee, 0x15, 0x4b, 0x8f, 0x6d },
        { 0xf7, 0xc0, 0x13, 0xac, 0x5b, 0x2b, 0x89, 0x52 }
    },
    {
        { 0x78, 0x33, 0x48, 0xe7, 0x5a, 0xeb, 0x0f, 0x2f,
          0xd7, 0xb1, 0x69, 0xbb, 0x8d, 0xc1, 0x67, 0x87 },
        { 0xF7, 0xC0, 0x13, 0xAC, 0x5B, 0x2B, 0x89, 0x52 },
        { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 }
    },
    {
        { 0xDC, 0x49, 0xdb, 0x13, 0x75, 0xa5, 0x58, 0x4f,
          0x64, 0x85, 0xb4, 0x13, 0xb5, 0xf1, 0x2b, 0xaf },
        { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 },
        { 0x65, 0xc1, 0x78, 0xb2, 0x84, 0xd1, 0x97, 0xcc }
    }
    };
    unsigned char tmp[2][8];
    int x, y, err;
    symmetric_key key;

    for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
       /* setup key */
       if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) {
          return err;
       }

       /* encrypt and decrypt */
       rc5_ecb_encrypt(tests[x].pt, tmp[0], &key);
       rc5_ecb_decrypt(tmp[0], tmp[1], &key);

       /* compare */
       if (XMEMCMP(tmp[0], tests[x].ct, 8) != 0 || XMEMCMP(tmp[1], tests[x].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++) rc5_ecb_encrypt(tmp[0], tmp[0], &key);
       for (y = 0; y < 1000; y++) rc5_ecb_decrypt(tmp[0], tmp[0], &key);
       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 rc5_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 rc5_keysize(int *keysize)
 {
    LTC_ARGCHK(keysize != NULL);
    if (*keysize < 8) {
       return CRYPT_INVALID_KEYSIZE;
    } else if (*keysize > 128) {
       *keysize = 128;
    }
    return CRYPT_OK;
 }

 #endif


 /* $Source: /cvs/libtom/libtomcrypt/src/ciphers/rc5.c,v $ */
 /* $Revision: 1.12 $ */
 /* $Date: 2006/11/08 23:01:06 $ */
	/* 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 rc5.c
	RC5 code by Tom St Denis
	*/

	#include "tomcrypt.h"

	#ifdef RC5

	const struct ltc_cipher_descriptor rc5_desc =
	{
	"rc5",
	2,
	8, 128, 8, 12,
	&rc5_setup,
	&rc5_ecb_encrypt,
	&rc5_ecb_decrypt,
	&rc5_test,
	&rc5_done,
	&rc5_keysize,
	NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
	};

	static const ulong32 stab[50] = {
	0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL,
	0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL,
	0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL,
	0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL,
	0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL,
	0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL, 0xe96a3d2fUL, 0x87a1b6e8UL, 0x25d930a1UL, 0xc410aa5aUL,
	0x62482413UL, 0x007f9dccUL
	};

	/**
	Initialize the RC5 block cipher
	@param key The symmetric key you wish to pass
	@param keylen The key length in bytes
	@param num_rounds The number of rounds desired (0 for default)
	@param skey The key in as scheduled by this function.
	@return CRYPT_OK if successful
	*/
	#ifdef LTC_CLEAN_STACK
	static int _rc5_setup(const unsigned char key, int keylen, int num_rounds, symmetric_key skey)
	#else
	int rc5_setup(const unsigned char key, int keylen, int num_rounds, symmetric_key skey)
	#endif
	{
	ulong32 L[64], *S, A, B, i, j, v, s, t, l;

	LTC_ARGCHK(skey != NULL);
	LTC_ARGCHK(key != NULL);

	/* test parameters */
	if (num_rounds == 0) {
	num_rounds = rc5_desc.default_rounds;
	}

	if (num_rounds < 12 \|\| num_rounds > 24) {
	return CRYPT_INVALID_ROUNDS;
	}

	/* key must be between 64 and 1024 bits */
	if (keylen < 8 \|\| keylen > 128) {
	return CRYPT_INVALID_KEYSIZE;
	}

	skey->rc5.rounds = num_rounds;
	S = skey->rc5.K;

	/* copy the key into the L array */
	for (A = i = j = 0; i < (ulong32)keylen; ) {
	A = (A << 8) \| ((ulong32)(key[i++] & 255));
	if ((i & 3) == 0) {
	L[j++] = BSWAP(A);
	A = 0;
	}
	}

	if ((keylen & 3) != 0) {
	A <<= (ulong32)((8 * (4 - (keylen&3))));
	L[j++] = BSWAP(A);
	}

	/* setup the S array */
	t = (ulong32)(2 * (num_rounds + 1));
	XMEMCPY(S, stab, t * sizeof(*S));

	/* mix buffer */
	s = 3 * MAX(t, j);
	l = j;
	for (A = B = i = j = v = 0; v < s; v++) {
	A = S[i] = ROLc(S[i] + A + B, 3);
	B = L[j] = ROL(L[j] + A + B, (A+B));
	if (++i == t) { i = 0; }
	if (++j == l) { j = 0; }
	}
	return CRYPT_OK;
	}

	#ifdef LTC_CLEAN_STACK
	int rc5_setup(const unsigned char key, int keylen, int num_rounds, symmetric_key skey)
	{
	int x;
	x = _rc5_setup(key, keylen, num_rounds, skey);
	burn_stack(sizeof(ulong32) * 122 + sizeof(int));
	return x;
	}
	#endif

	/**
	Encrypts a block of text with RC5
	@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
	*/
	#ifdef LTC_CLEAN_STACK
	static int _rc5_ecb_encrypt(const unsigned char pt, unsigned char ct, symmetric_key *skey)
	#else
	int rc5_ecb_encrypt(const unsigned char pt, unsigned char ct, symmetric_key *skey)
	#endif
	{
	ulong32 A, B, *K;
	int r;
	LTC_ARGCHK(skey != NULL);
	LTC_ARGCHK(pt != NULL);
	LTC_ARGCHK(ct != NULL);

	LOAD32L(A, &pt[0]);
	LOAD32L(B, &pt[4]);
	A += skey->rc5.K[0];
	B += skey->rc5.K[1];
	K = skey->rc5.K + 2;

	if ((skey->rc5.rounds & 1) == 0) {
	for (r = 0; r < skey->rc5.rounds; r += 2) {
	A = ROL(A ^ B, B) + K[0];
	B = ROL(B ^ A, A) + K[1];
	A = ROL(A ^ B, B) + K[2];
	B = ROL(B ^ A, A) + K[3];
	K += 4;
	}
	} else {
	for (r = 0; r < skey->rc5.rounds; r++) {
	A = ROL(A ^ B, B) + K[0];
	B = ROL(B ^ A, A) + K[1];
	K += 2;
	}
	}
	STORE32L(A, &ct[0]);
	STORE32L(B, &ct[4]);

	return CRYPT_OK;
	}

	#ifdef LTC_CLEAN_STACK
	int rc5_ecb_encrypt(const unsigned char pt, unsigned char ct, symmetric_key *skey)
	{
	int err = _rc5_ecb_encrypt(pt, ct, skey);
	burn_stack(sizeof(ulong32) * 2 + sizeof(int));
	return err;
	}
	#endif

	/**
	Decrypts a block of text with RC5
	@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
	*/
	#ifdef LTC_CLEAN_STACK
	static int _rc5_ecb_decrypt(const unsigned char ct, unsigned char pt, symmetric_key *skey)
	#else
	int rc5_ecb_decrypt(const unsigned char ct, unsigned char pt, symmetric_key *skey)
	#endif
	{
	ulong32 A, B, *K;
	int r;
	LTC_ARGCHK(skey != NULL);
	LTC_ARGCHK(pt != NULL);
	LTC_ARGCHK(ct != NULL);

	LOAD32L(A, &ct[0]);
	LOAD32L(B, &ct[4]);
	K = skey->rc5.K + (skey->rc5.rounds << 1);

	if ((skey->rc5.rounds & 1) == 0) {
	K -= 2;
	for (r = skey->rc5.rounds - 1; r >= 0; r -= 2) {
	B = ROR(B - K[3], A) ^ A;
	A = ROR(A - K[2], B) ^ B;
	B = ROR(B - K[1], A) ^ A;
	A = ROR(A - K[0], B) ^ B;
	K -= 4;
	}
	} else {
	for (r = skey->rc5.rounds - 1; r >= 0; r--) {
	B = ROR(B - K[1], A) ^ A;
	A = ROR(A - K[0], B) ^ B;
	K -= 2;
	}
	}
	A -= skey->rc5.K[0];
	B -= skey->rc5.K[1];
	STORE32L(A, &pt[0]);
	STORE32L(B, &pt[4]);

	return CRYPT_OK;
	}

	#ifdef LTC_CLEAN_STACK
	int rc5_ecb_decrypt(const unsigned char ct, unsigned char pt, symmetric_key *skey)
	{
	int err = _rc5_ecb_decrypt(ct, pt, skey);
	burn_stack(sizeof(ulong32) * 2 + sizeof(int));
	return err;
	}
	#endif

	/**
	Performs a self-test of the RC5 block cipher
	@return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
	*/
	int rc5_test(void)
	{
	#ifndef LTC_TEST
	return CRYPT_NOP;
	#else
	static const struct {
	unsigned char key[16], pt[8], ct[8];
	} tests[] = {
	{
	{ 0x91, 0x5f, 0x46, 0x19, 0xbe, 0x41, 0xb2, 0x51,
	0x63, 0x55, 0xa5, 0x01, 0x10, 0xa9, 0xce, 0x91 },
	{ 0x21, 0xa5, 0xdb, 0xee, 0x15, 0x4b, 0x8f, 0x6d },
	{ 0xf7, 0xc0, 0x13, 0xac, 0x5b, 0x2b, 0x89, 0x52 }
	},
	{
	{ 0x78, 0x33, 0x48, 0xe7, 0x5a, 0xeb, 0x0f, 0x2f,
	0xd7, 0xb1, 0x69, 0xbb, 0x8d, 0xc1, 0x67, 0x87 },
	{ 0xF7, 0xC0, 0x13, 0xAC, 0x5B, 0x2B, 0x89, 0x52 },
	{ 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 }
	},
	{
	{ 0xDC, 0x49, 0xdb, 0x13, 0x75, 0xa5, 0x58, 0x4f,
	0x64, 0x85, 0xb4, 0x13, 0xb5, 0xf1, 0x2b, 0xaf },
	{ 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 },
	{ 0x65, 0xc1, 0x78, 0xb2, 0x84, 0xd1, 0x97, 0xcc }
	}
	};
	unsigned char tmp[2][8];
	int x, y, err;
	symmetric_key key;

	for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
	/* setup key */
	if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) {
	return err;
	}

	/* encrypt and decrypt */
	rc5_ecb_encrypt(tests[x].pt, tmp[0], &key);
	rc5_ecb_decrypt(tmp[0], tmp[1], &key);

	/* compare */
	if (XMEMCMP(tmp[0], tests[x].ct, 8) != 0 \|\| XMEMCMP(tmp[1], tests[x].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++) rc5_ecb_encrypt(tmp[0], tmp[0], &key);
	for (y = 0; y < 1000; y++) rc5_ecb_decrypt(tmp[0], tmp[0], &key);
	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 rc5_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 rc5_keysize(int *keysize)
	{
	LTC_ARGCHK(keysize != NULL);
	if (*keysize < 8) {
	return CRYPT_INVALID_KEYSIZE;
	} else if (*keysize > 128) {
	*keysize = 128;
	}
	return CRYPT_OK;
	}

	#endif




	/* $Source: /cvs/libtom/libtomcrypt/src/ciphers/rc5.c,v $ */
	/* $Revision: 1.12 $ */
	/* $Date: 2006/11/08 23:01:06 $ */