/* crypto/des/ofb64ede.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 "des_locl.h"
/* The input and output encrypted as though 64bit ofb mode is being
* used. The extra state information to record how much of the
* 64bit block we have used is contained in *num;
*/
void DES_ede3_ofb64_encrypt(register const unsigned char *in,
register unsigned char *out, long length,
DES_key_schedule *k1, DES_key_schedule *k2,
DES_key_schedule *k3, DES_cblock *ivec,
int *num)
{
register DES_LONG v0,v1;
register int n= *num;
register long l=length;
DES_cblock d;
register char *dp;
DES_LONG ti[2];
unsigned char *iv;
int save=0;
iv = &(*ivec)[0];
c2l(iv,v0);
c2l(iv,v1);
ti[0]=v0;
ti[1]=v1;
dp=(char *)d;
l2c(v0,dp);
l2c(v1,dp);
while (l--)
{
if (n == 0)
{
/* ti[0]=v0; */
/* ti[1]=v1; */
DES_encrypt3(ti,k1,k2,k3);
v0=ti[0];
v1=ti[1];
dp=(char *)d;
l2c(v0,dp);
l2c(v1,dp);
save++;
}
*(out++)= *(in++)^d[n];
n=(n+1)&0x07;
}
if (save)
{
/* v0=ti[0];
v1=ti[1];*/
iv = &(*ivec)[0];
l2c(v0,iv);
l2c(v1,iv);
}
v0=v1=ti[0]=ti[1]=0;
*num=n;
}
#ifdef undef /* MACRO */
void DES_ede2_ofb64_encrypt(register unsigned char *in,
register unsigned char *out, long length, DES_key_schedule k1,
DES_key_schedule k2, DES_cblock (*ivec), int *num)
{
DES_ede3_ofb64_encrypt(in, out, length, k1,k2,k1, ivec, num);
}
#endif
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=pod
=head1 NAME
BN_mod_mul_reciprocal, BN_div_recp, BN_RECP_CTX_new, BN_RECP_CTX_init,
BN_RECP_CTX_free, BN_RECP_CTX_set - modular multiplication using
reciprocal
=head1 SYNOPSIS
#include <openssl/bn.h>
BN_RECP_CTX *BN_RECP_CTX_new(void);
void BN_RECP_CTX_init(BN_RECP_CTX *recp);
void BN_RECP_CTX_free(BN_RECP_CTX *recp);
int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *m, BN_CTX *ctx);
int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *a, BN_RECP_CTX *recp,
BN_CTX *ctx);
int BN_mod_mul_reciprocal(BIGNUM *r, BIGNUM *a, BIGNUM *b,
BN_RECP_CTX *recp, BN_CTX *ctx);
=head1 DESCRIPTION
BN_mod_mul_reciprocal() can be used to perform an efficient
L<BN_mod_mul(3)|BN_mod_mul(3)> operation when the operation will be performed
repeatedly with the same modulus. It computes B<r>=(B<a>*B<b>)%B<m>
using B<recp>=1/B<m>, which is set as described below. B<ctx> is a
previously allocated B<BN_CTX> used for temporary variables.
BN_RECP_CTX_new() allocates and initializes a B<BN_RECP> structure.
BN_RECP_CTX_init() initializes an existing uninitialized B<BN_RECP>.
BN_RECP_CTX_free() frees the components of the B<BN_RECP>, and, if it
was created by BN_RECP_CTX_new(), also the structure itself.
BN_RECP_CTX_set() stores B<m> in B<recp> and sets it up for computing
1/B<m> and shifting it left by BN_num_bits(B<m>)+1 to make it an
integer. The result and the number of bits it was shifted left will
later be stored in B<recp>.
BN_div_recp() divides B<a> by B<m> using B<recp>. It places the quotient
in B<dv> and the remainder in B<rem>.
The B<BN_RECP_CTX> structure is defined as follows:
typedef struct bn_recp_ctx_st
{
BIGNUM N; /* the divisor */
BIGNUM Nr; /* the reciprocal */
int num_bits;
int shift;
int flags;
} BN_RECP_CTX;
It cannot be shared between threads.
=head1 RETURN VALUES
BN_RECP_CTX_new() returns the newly allocated B<BN_RECP_CTX>, and NULL
on error.
BN_RECP_CTX_init() and BN_RECP_CTX_free() have no return values.
For the other functions, 1 is returned for success, 0 on error.
The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
=head1 SEE ALSO
L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)>,
L<BN_CTX_new(3)|BN_CTX_new(3)>
=head1 HISTORY
B<BN_RECP_CTX> was added in SSLeay 0.9.0. Before that, the function
BN_reciprocal() was used instead, and the BN_mod_mul_reciprocal()
arguments were different.
=cut
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