code / widevine-mirrored-source / 66427ffa50c9a1038998509907e91d0be9ced12a / . / openssl-1.0.0a / crypto / des / ofb_enc.c

/* crypto/des/ofb_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 "des_locl.h" | |

/* The input and output are loaded in multiples of 8 bits. | |

* What this means is that if you hame numbits=12 and length=2 | |

* the first 12 bits will be retrieved from the first byte and half | |

* the second. The second 12 bits will come from the 3rd and half the 4th | |

* byte. | |

*/ | |

void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, | |

long length, DES_key_schedule *schedule, | |

DES_cblock *ivec) | |

{ | |

register DES_LONG d0,d1,vv0,vv1,v0,v1,n=(numbits+7)/8; | |

register DES_LONG mask0,mask1; | |

register long l=length; | |

register int num=numbits; | |

DES_LONG ti[2]; | |

unsigned char *iv; | |

if (num > 64) return; | |

if (num > 32) | |

{ | |

mask0=0xffffffffL; | |

if (num >= 64) | |

mask1=mask0; | |

else | |

mask1=(1L<<(num-32))-1; | |

} | |

else | |

{ | |

if (num == 32) | |

mask0=0xffffffffL; | |

else | |

mask0=(1L<<num)-1; | |

mask1=0x00000000L; | |

} | |

iv = &(*ivec)[0]; | |

c2l(iv,v0); | |

c2l(iv,v1); | |

ti[0]=v0; | |

ti[1]=v1; | |

while (l-- > 0) | |

{ | |

ti[0]=v0; | |

ti[1]=v1; | |

DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); | |

vv0=ti[0]; | |

vv1=ti[1]; | |

c2ln(in,d0,d1,n); | |

in+=n; | |

d0=(d0^vv0)&mask0; | |

d1=(d1^vv1)&mask1; | |

l2cn(d0,d1,out,n); | |

out+=n; | |

if (num == 32) | |

{ v0=v1; v1=vv0; } | |

else if (num == 64) | |

{ v0=vv0; v1=vv1; } | |

else if (num > 32) /* && num != 64 */ | |

{ | |

v0=((v1>>(num-32))|(vv0<<(64-num)))&0xffffffffL; | |

v1=((vv0>>(num-32))|(vv1<<(64-num)))&0xffffffffL; | |

} | |

else /* num < 32 */ | |

{ | |

v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL; | |

v1=((v1>>num)|(vv0<<(32-num)))&0xffffffffL; | |

} | |

} | |

iv = &(*ivec)[0]; | |

l2c(v0,iv); | |

l2c(v1,iv); | |

v0=v1=d0=d1=ti[0]=ti[1]=vv0=vv1=0; | |

} | |