[thirdparty/openssl.git] / crypto / evp / evp_enc.c

/* crypto/evp/evp_enc.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/evp.h>
#include <openssl/err.h>

const char *EVP_version="EVP" OPENSSL_VERSION_PTEXT;

void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *ctx)
	{
	memset(ctx,0,sizeof(EVP_CIPHER_CTX));
	/* ctx->cipher=NULL; */
	}

int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
	     unsigned char *key, unsigned char *iv, int enc)
	{
	if(enc) enc = 1;
	if (cipher) {
		ctx->cipher=cipher;
		ctx->key_len = cipher->key_len;
	} else if(!ctx->cipher) {
		EVPerr(EVP_F_EVP_CIPHERINIT, EVP_R_NO_CIPHER_SET);
		return 0;
	}
	if(!(EVP_CIPHER_CTX_flags(ctx) & EVP_CIPH_CUSTOM_IV)) {
		switch(EVP_CIPHER_CTX_mode(ctx)) {

			case EVP_CIPH_STREAM_CIPHER:
			case EVP_CIPH_ECB_MODE:
			break;

			case EVP_CIPH_CFB_MODE:
			case EVP_CIPH_OFB_MODE:

			ctx->num = 0;

			case EVP_CIPH_CBC_MODE:

			if(iv) memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
			memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
			break;

			default:
			return 0;
			break;
		}
	}

	if(key || (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT)) {
		if(!ctx->cipher->init(ctx,key,iv,enc)) return 0;
	}
	ctx->encrypt=enc;
	ctx->buf_len=0;
	return 1;
	}

int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
	     unsigned char *in, int inl)
	{
	if (ctx->encrypt)
		return EVP_EncryptUpdate(ctx,out,outl,in,inl);
	else	return EVP_DecryptUpdate(ctx,out,outl,in,inl);
	}

int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
	{
	if (ctx->encrypt)
		return EVP_EncryptFinal(ctx,out,outl);
	else	return(EVP_DecryptFinal(ctx,out,outl));
	}

int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
	     unsigned char *key, unsigned char *iv)
	{
	return EVP_CipherInit(ctx, cipher, key, iv, 1);
	}

int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
	     unsigned char *key, unsigned char *iv)
	{
	return EVP_CipherInit(ctx, cipher, key, iv, 0);
	}


int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
	     unsigned char *in, int inl)
	{
	int i,j,bl;

	i=ctx->buf_len;
	bl=ctx->cipher->block_size;
	*outl=0;
	if ((inl == 0) && (i != bl)) return 1;
	if (i != 0)
		{
		if (i+inl < bl)
			{
			memcpy(&(ctx->buf[i]),in,inl);
			ctx->buf_len+=inl;
			return 1;
			}
		else
			{
			j=bl-i;
			if (j != 0) memcpy(&(ctx->buf[i]),in,j);
			if(!ctx->cipher->do_cipher(ctx,out,ctx->buf,bl)) return 0;
			inl-=j;
			in+=j;
			out+=bl;
			*outl+=bl;
			}
		}
	i=inl%bl; /* how much is left */
	inl-=i;
	if (inl > 0)
		{
		if(!ctx->cipher->do_cipher(ctx,out,in,inl)) return 0;
		*outl+=inl;
		}

	if (i != 0)
		memcpy(ctx->buf,&(in[inl]),i);
	ctx->buf_len=i;
	return 1;
	}

int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
	{
	int i,n,b,bl;

	b=ctx->cipher->block_size;
	if (b == 1)
		{
		*outl=0;
		return 1;
		}
	bl=ctx->buf_len;
	n=b-bl;
	for (i=bl; i<b; i++)
		ctx->buf[i]=n;
	if(!ctx->cipher->do_cipher(ctx,out,ctx->buf,b)) return 0;
	*outl=b;
	return 1;
	}

int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
	     unsigned char *in, int inl)
	{
	int b,bl,n;
	int keep_last=0;

	*outl=0;
	if (inl == 0) return 1;

	b=ctx->cipher->block_size;
	if (b > 1)
		{
		/* Is the input a multiple of the block size? */
		bl=ctx->buf_len;
		n=inl+bl;
		if (n%b == 0)
			{
			if (inl < b) /* must be 'just one' buff */
				{
				memcpy(&(ctx->buf[bl]),in,inl);
				ctx->buf_len=b;
				*outl=0;
				return 1;
				}
			keep_last=1;
			inl-=b; /* don't do the last block */
			}
		}
	if(!EVP_EncryptUpdate(ctx,out,outl,in,inl)) return 0;

	/* if we have 'decrypted' a multiple of block size, make sure
	 * we have a copy of this last block */
	if (keep_last)
		{
		memcpy(&(ctx->buf[0]),&(in[inl]),b);
#ifdef DEBUG
		if (ctx->buf_len != 0)
			{
			abort();
			}
#endif
		ctx->buf_len=b;
		}
	return 1;
	}

int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
	{
	int i,b;
	int n;

	*outl=0;
	b=ctx->cipher->block_size;
	if (b > 1)
		{
		if (ctx->buf_len != b)
			{
			EVPerr(EVP_F_EVP_DECRYPTFINAL,EVP_R_WRONG_FINAL_BLOCK_LENGTH);
			return(0);
			}
		if(!EVP_EncryptUpdate(ctx,ctx->buf,&n,ctx->buf,0)) return 0;
		if (n != b)
			return(0);
		n=ctx->buf[b-1];
		if (n > b)
			{
			EVPerr(EVP_F_EVP_DECRYPTFINAL,EVP_R_BAD_DECRYPT);
			return(0);
			}
		for (i=0; i<n; i++)
			{
			if (ctx->buf[--b] != n)
				{
				EVPerr(EVP_F_EVP_DECRYPTFINAL,EVP_R_BAD_DECRYPT);
				return(0);
				}
			}
		n=ctx->cipher->block_size-n;
		for (i=0; i<n; i++)
			out[i]=ctx->buf[i];
		*outl=n;
		}
	else
		*outl=0;
	return(1);
	}

int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *c)
	{
	if ((c->cipher != NULL) && (c->cipher->cleanup != NULL))
		{
		if(!c->cipher->cleanup(c)) return 0;
		}
	memset(c,0,sizeof(EVP_CIPHER_CTX));
	return 1;
	}

int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
	{
	if(c->key_len == keylen) return 1;
	if((keylen > 0) && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH))
		{
		c->key_len = keylen;
		return 1;
		}
	EVPerr(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH,EVP_R_INVALID_KEY_LENGTH);
	return 0;
	}
Commit	Line	Data
d02b48c6	1	/* crypto/evp/evp_enc.c */
58964a49	2	/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
d02b48c6 RE	3	* All rights reserved.
	4	*
	5	* This package is an SSL implementation written
	6	* by Eric Young (eay@cryptsoft.com).
	7	* The implementation was written so as to conform with Netscapes SSL.
	8	*
	9	* This library is free for commercial and non-commercial use as long as
	10	* the following conditions are aheared to. The following conditions
	11	* apply to all code found in this distribution, be it the RC4, RSA,
	12	* lhash, DES, etc., code; not just the SSL code. The SSL documentation
	13	* included with this distribution is covered by the same copyright terms
	14	* except that the holder is Tim Hudson (tjh@cryptsoft.com).
	15	*
	16	* Copyright remains Eric Young's, and as such any Copyright notices in
	17	* the code are not to be removed.
	18	* If this package is used in a product, Eric Young should be given attribution
	19	* as the author of the parts of the library used.
	20	* This can be in the form of a textual message at program startup or
	21	* in documentation (online or textual) provided with the package.
	22	*
	23	* Redistribution and use in source and binary forms, with or without
	24	* modification, are permitted provided that the following conditions
	25	* are met:
	26	* 1. Redistributions of source code must retain the copyright
	27	* notice, this list of conditions and the following disclaimer.
	28	* 2. Redistributions in binary form must reproduce the above copyright
	29	* notice, this list of conditions and the following disclaimer in the
	30	* documentation and/or other materials provided with the distribution.
	31	* 3. All advertising materials mentioning features or use of this software
	32	* must display the following acknowledgement:
	33	* "This product includes cryptographic software written by
	34	* Eric Young (eay@cryptsoft.com)"
	35	* The word 'cryptographic' can be left out if the rouines from the library
	36	* being used are not cryptographic related :-).
	37	* 4. If you include any Windows specific code (or a derivative thereof) from
	38	* the apps directory (application code) you must include an acknowledgement:
	39	* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
	40	*
	41	* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
	42	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	43	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	44	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	45	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	46	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	47	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	48	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	49	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	50	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	51	* SUCH DAMAGE.
	52	*
	53	* The licence and distribution terms for any publically available version or
	54	* derivative of this code cannot be changed. i.e. this code cannot simply be
	55	* copied and put under another distribution licence
	56	* [including the GNU Public Licence.]
	57	*/
	58
	59	#include <stdio.h>
	60	#include "cryptlib.h"
ec577822	61	#include <openssl/evp.h>
7f060601	62	#include <openssl/err.h>
d02b48c6	63
e778802f	64	const char *EVP_version="EVP" OPENSSL_VERSION_PTEXT;
58964a49	65
6b691a5c	66	void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *ctx)
58964a49 RE	67	{
	68	memset(ctx,0,sizeof(EVP_CIPHER_CTX));
	69	/* ctx->cipher=NULL; */
	70	}
d02b48c6	71
360370d9	72	int EVP_CipherInit(EVP_CIPHER_CTX ctx, const EVP_CIPHER cipher,
6b691a5c	73	unsigned char key, unsigned char iv, int enc)
d02b48c6	74	{
360370d9 DSH	75	if(enc) enc = 1;
	76	if (cipher) {
	77	ctx->cipher=cipher;
	78	ctx->key_len = cipher->key_len;
	79	} else if(!ctx->cipher) {
	80	EVPerr(EVP_F_EVP_CIPHERINIT, EVP_R_NO_CIPHER_SET);
	81	return 0;
	82	}
	83	if(!(EVP_CIPHER_CTX_flags(ctx) & EVP_CIPH_CUSTOM_IV)) {
	84	switch(EVP_CIPHER_CTX_mode(ctx)) {
	85
	86	case EVP_CIPH_STREAM_CIPHER:
	87	case EVP_CIPH_ECB_MODE:
	88	break;
	89
	90	case EVP_CIPH_CFB_MODE:
	91	case EVP_CIPH_OFB_MODE:
	92
	93	ctx->num = 0;
	94
	95	case EVP_CIPH_CBC_MODE:
	96
	97	if(iv) memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
	98	memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
	99	break;
	100
	101	default:
	102	return 0;
	103	break;
	104	}
	105	}
	106
	107	if(key \|\| (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT)) {
	108	if(!ctx->cipher->init(ctx,key,iv,enc)) return 0;
	109	}
	110	ctx->encrypt=enc;
	111	ctx->buf_len=0;
	112	return 1;
d02b48c6 RE	113	}
d02b48c6 RE	114
be06a934	115	int EVP_CipherUpdate(EVP_CIPHER_CTX ctx, unsigned char out, int *outl,
6b691a5c	116	unsigned char *in, int inl)
d02b48c6 RE	117	{
d02b48c6 RE	118	if (ctx->encrypt)
be06a934 DSH	119	return EVP_EncryptUpdate(ctx,out,outl,in,inl);
be06a934 DSH	120	else return EVP_DecryptUpdate(ctx,out,outl,in,inl);
d02b48c6 RE	121	}
d02b48c6 RE	122
6b691a5c	123	int EVP_CipherFinal(EVP_CIPHER_CTX ctx, unsigned char out, int *outl)
d02b48c6 RE	124	{
d02b48c6 RE	125	if (ctx->encrypt)
be06a934	126	return EVP_EncryptFinal(ctx,out,outl);
d02b48c6 RE	127	else return(EVP_DecryptFinal(ctx,out,outl));
	128	}
	129
be06a934	130	int EVP_EncryptInit(EVP_CIPHER_CTX ctx, const EVP_CIPHER cipher,
6b691a5c	131	unsigned char key, unsigned char iv)
d02b48c6	132	{
360370d9	133	return EVP_CipherInit(ctx, cipher, key, iv, 1);
d02b48c6 RE	134	}
d02b48c6 RE	135
be06a934	136	int EVP_DecryptInit(EVP_CIPHER_CTX ctx, const EVP_CIPHER cipher,
6b691a5c	137	unsigned char key, unsigned char iv)
d02b48c6	138	{
360370d9	139	return EVP_CipherInit(ctx, cipher, key, iv, 0);
d02b48c6 RE	140	}
	141
	142
be06a934	143	int EVP_EncryptUpdate(EVP_CIPHER_CTX ctx, unsigned char out, int *outl,
6b691a5c	144	unsigned char *in, int inl)
d02b48c6 RE	145	{
	146	int i,j,bl;
	147
	148	i=ctx->buf_len;
	149	bl=ctx->cipher->block_size;
	150	*outl=0;
be06a934	151	if ((inl == 0) && (i != bl)) return 1;
d02b48c6 RE	152	if (i != 0)
	153	{
	154	if (i+inl < bl)
	155	{
	156	memcpy(&(ctx->buf[i]),in,inl);
	157	ctx->buf_len+=inl;
be06a934	158	return 1;
d02b48c6 RE	159	}
	160	else
	161	{
	162	j=bl-i;
	163	if (j != 0) memcpy(&(ctx->buf[i]),in,j);
be06a934	164	if(!ctx->cipher->do_cipher(ctx,out,ctx->buf,bl)) return 0;
d02b48c6 RE	165	inl-=j;
	166	in+=j;
	167	out+=bl;
	168	*outl+=bl;
	169	}
	170	}
	171	i=inl%bl; /* how much is left */
	172	inl-=i;
	173	if (inl > 0)
	174	{
be06a934	175	if(!ctx->cipher->do_cipher(ctx,out,in,inl)) return 0;
d02b48c6 RE	176	*outl+=inl;
	177	}
	178
	179	if (i != 0)
	180	memcpy(ctx->buf,&(in[inl]),i);
	181	ctx->buf_len=i;
be06a934	182	return 1;
d02b48c6 RE	183	}
d02b48c6 RE	184
be06a934	185	int EVP_EncryptFinal(EVP_CIPHER_CTX ctx, unsigned char out, int *outl)
d02b48c6 RE	186	{
	187	int i,n,b,bl;
	188
	189	b=ctx->cipher->block_size;
	190	if (b == 1)
	191	{
	192	*outl=0;
be06a934	193	return 1;
d02b48c6 RE	194	}
	195	bl=ctx->buf_len;
	196	n=b-bl;
	197	for (i=bl; i<b; i++)
	198	ctx->buf[i]=n;
be06a934	199	if(!ctx->cipher->do_cipher(ctx,out,ctx->buf,b)) return 0;
d02b48c6	200	*outl=b;
be06a934	201	return 1;
d02b48c6 RE	202	}
d02b48c6 RE	203
be06a934	204	int EVP_DecryptUpdate(EVP_CIPHER_CTX ctx, unsigned char out, int *outl,
6b691a5c	205	unsigned char *in, int inl)
d02b48c6 RE	206	{
	207	int b,bl,n;
	208	int keep_last=0;
	209
	210	*outl=0;
be06a934	211	if (inl == 0) return 1;
d02b48c6 RE	212
	213	b=ctx->cipher->block_size;
	214	if (b > 1)
	215	{
	216	/* Is the input a multiple of the block size? */
	217	bl=ctx->buf_len;
	218	n=inl+bl;
	219	if (n%b == 0)
	220	{
	221	if (inl < b) /* must be 'just one' buff */
	222	{
	223	memcpy(&(ctx->buf[bl]),in,inl);
	224	ctx->buf_len=b;
	225	*outl=0;
be06a934	226	return 1;
d02b48c6 RE	227	}
	228	keep_last=1;
	229	inl-=b; /* don't do the last block */
	230	}
	231	}
be06a934	232	if(!EVP_EncryptUpdate(ctx,out,outl,in,inl)) return 0;
d02b48c6 RE	233
	234	/* if we have 'decrypted' a multiple of block size, make sure
	235	* we have a copy of this last block */
	236	if (keep_last)
	237	{
	238	memcpy(&(ctx->buf[0]),&(in[inl]),b);
	239	#ifdef DEBUG
	240	if (ctx->buf_len != 0)
	241	{
	242	abort();
	243	}
	244	#endif
	245	ctx->buf_len=b;
	246	}
be06a934	247	return 1;
d02b48c6 RE	248	}
d02b48c6 RE	249
6b691a5c	250	int EVP_DecryptFinal(EVP_CIPHER_CTX ctx, unsigned char out, int *outl)
d02b48c6 RE	251	{
	252	int i,b;
	253	int n;
	254
	255	*outl=0;
	256	b=ctx->cipher->block_size;
	257	if (b > 1)
	258	{
	259	if (ctx->buf_len != b)
	260	{
	261	EVPerr(EVP_F_EVP_DECRYPTFINAL,EVP_R_WRONG_FINAL_BLOCK_LENGTH);
	262	return(0);
	263	}
be06a934	264	if(!EVP_EncryptUpdate(ctx,ctx->buf,&n,ctx->buf,0)) return 0;
d02b48c6 RE	265	if (n != b)
	266	return(0);
	267	n=ctx->buf[b-1];
	268	if (n > b)
	269	{
	270	EVPerr(EVP_F_EVP_DECRYPTFINAL,EVP_R_BAD_DECRYPT);
	271	return(0);
	272	}
	273	for (i=0; i<n; i++)
	274	{
	275	if (ctx->buf[--b] != n)
	276	{
	277	EVPerr(EVP_F_EVP_DECRYPTFINAL,EVP_R_BAD_DECRYPT);
	278	return(0);
	279	}
	280	}
	281	n=ctx->cipher->block_size-n;
	282	for (i=0; i<n; i++)
	283	out[i]=ctx->buf[i];
	284	*outl=n;
	285	}
	286	else
	287	*outl=0;
	288	return(1);
	289	}
	290
be06a934	291	int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *c)
d02b48c6 RE	292	{
d02b48c6 RE	293	if ((c->cipher != NULL) && (c->cipher->cleanup != NULL))
be06a934 DSH	294	{
	295	if(!c->cipher->cleanup(c)) return 0;
	296	}
d02b48c6	297	memset(c,0,sizeof(EVP_CIPHER_CTX));
be06a934	298	return 1;
d02b48c6 RE	299	}
d02b48c6 RE	300
7f060601 DSH	301	int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
	302	{
	303	if(c->key_len == keylen) return 1;
	304	if((keylen > 0) && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH))
	305	{
	306	c->key_len = keylen;
	307	return 1;
	308	}
	309	EVPerr(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH,EVP_R_INVALID_KEY_LENGTH);
	310	return 0;
	311	}
	312