c_cfb64.c 4.3 KB

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  1. /* crypto/cast/c_cfb64.c */
  2. /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  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. #include <openssl/cast.h>
  59. #include "cast_lcl.h"
  60. /* The input and output encrypted as though 64bit cfb mode is being
  61. * used. The extra state information to record how much of the
  62. * 64bit block we have used is contained in *num;
  63. */
  64. void CAST_cfb64_encrypt(const unsigned char *in, unsigned char *out,
  65. long length, const CAST_KEY *schedule, unsigned char *ivec,
  66. int *num, int enc)
  67. {
  68. register CAST_LONG v0,v1,t;
  69. register int n= *num;
  70. register long l=length;
  71. CAST_LONG ti[2];
  72. unsigned char *iv,c,cc;
  73. iv=ivec;
  74. if (enc)
  75. {
  76. while (l--)
  77. {
  78. if (n == 0)
  79. {
  80. n2l(iv,v0); ti[0]=v0;
  81. n2l(iv,v1); ti[1]=v1;
  82. CAST_encrypt((CAST_LONG *)ti,schedule);
  83. iv=ivec;
  84. t=ti[0]; l2n(t,iv);
  85. t=ti[1]; l2n(t,iv);
  86. iv=ivec;
  87. }
  88. c= *(in++)^iv[n];
  89. *(out++)=c;
  90. iv[n]=c;
  91. n=(n+1)&0x07;
  92. }
  93. }
  94. else
  95. {
  96. while (l--)
  97. {
  98. if (n == 0)
  99. {
  100. n2l(iv,v0); ti[0]=v0;
  101. n2l(iv,v1); ti[1]=v1;
  102. CAST_encrypt((CAST_LONG *)ti,schedule);
  103. iv=ivec;
  104. t=ti[0]; l2n(t,iv);
  105. t=ti[1]; l2n(t,iv);
  106. iv=ivec;
  107. }
  108. cc= *(in++);
  109. c=iv[n];
  110. iv[n]=cc;
  111. *(out++)=c^cc;
  112. n=(n+1)&0x07;
  113. }
  114. }
  115. v0=v1=ti[0]=ti[1]=t=c=cc=0;
  116. *num=n;
  117. }