openssl/crypto/des/ofb64enc.c

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2023-05-09 22:08:48 +00:00
/*
* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "des_local.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_ofb64_encrypt(register const unsigned char *in,
register unsigned char *out, long length,
DES_key_schedule *schedule, DES_cblock *ivec, int *num)
{
register DES_LONG v0, v1, t;
register int n = *num;
register long l = length;
DES_cblock d;
register unsigned 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 = d;
l2c(v0, dp);
l2c(v1, dp);
while (l--) {
if (n == 0) {
DES_encrypt1(ti, schedule, DES_ENCRYPT);
dp = d;
t = ti[0];
l2c(t, dp);
t = ti[1];
l2c(t, 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);
}
t = v0 = v1 = ti[0] = ti[1] = 0;
*num = n;
}