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/* crypto/cast/c_cfb64.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 "cast.h"
#include "cast_lcl.h"
/* The input and output encrypted as though 64bit cfb mode is being
* used. The extra state information to record how much of the
* 64bit block we have used is contained in *num;
*/
void CAST_cfb64_encrypt(unsigned char *in, unsigned char *out, long length,
CAST_KEY *schedule, unsigned char *ivec, int *num, int encrypt)
{
register CAST_LONG v0,v1,t;
register int n= *num;
register long l=length;
CAST_LONG ti[2];
unsigned char *iv,c,cc;
iv=(unsigned char *)ivec;
if (encrypt)
{
while (l--)
{
if (n == 0)
{
n2l(iv,v0); ti[0]=v0;
n2l(iv,v1); ti[1]=v1;
CAST_encrypt((CAST_LONG *)ti,schedule);
iv=(unsigned char *)ivec;
t=ti[0]; l2n(t,iv);
t=ti[1]; l2n(t,iv);
iv=(unsigned char *)ivec;
}
c= *(in++)^iv[n];
*(out++)=c;
iv[n]=c;
n=(n+1)&0x07;
}
}
else
{
while (l--)
{
if (n == 0)
{
n2l(iv,v0); ti[0]=v0;
n2l(iv,v1); ti[1]=v1;
CAST_encrypt((CAST_LONG *)ti,schedule);
iv=(unsigned char *)ivec;
t=ti[0]; l2n(t,iv);
t=ti[1]; l2n(t,iv);
iv=(unsigned char *)ivec;
}
cc= *(in++);
c=iv[n];
iv[n]=cc;
*(out++)=c^cc;
n=(n+1)&0x07;
}
}
v0=v1=ti[0]=ti[1]=t=c=cc=0;
*num=n;
}
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