S-des Key Generation Code In C%2b%2b

P: 2
I have been asked to do a DES encryption project in C but pretty new to programming. I've found the following code in C++ but am not sure how to do the equivalent of classes in C.
I dont know the syntax of how to move from one section of code to the next. Do i have to declare seperate functions for each section even if its only a simple for loop section of code? for example how would i move from:
void Des::IP() //Initial Permutation -----> void Des::Expansio() //Permutation Choice-1
in code below:
  1. # include <stdio.h>
  2. # include <fstream.h>
  3. # include <string.h>
  4. # include <conio.h>
  5. # include <iostream.h>
  6. int key[64]={
  7. 0,0,0,1,0,0,1,1,
  8. 0,0,1,1,0,1,0,0,
  9. 0,1,0,1,0,1,1,1,
  10. 0,1,1,1,1,0,0,1,
  11. 1,0,0,1,1,0,1,1,
  12. 1,0,1,1,1,1,0,0,
  13. 1,1,0,1,1,1,1,1,
  14. 1,1,1,1,0,0,0,1
  15. };
  16. class Des
  17. {
  18. public:
  19. int keyi[16][48],
  20. total[64],
  21. left[32],
  22. right[32],
  23. ck[28],
  24. dk[28],
  25. expansion[48],
  26. z[48],
  27. xor1[48],
  28. sub[32],
  29. p[32],
  30. xor2[32],
  31. temp[64],
  32. pc1[56],
  33. ip[64],
  34. inv[8][8];
  35. char final[1000];
  36. void IP();
  37. void PermChoice1();
  38. void PermChoice2();
  39. void Expansion();
  40. void inverse();
  41. void xor_two();
  42. void xor_oneE(int);
  43. void xor_oneD(int);
  44. void substitution();
  45. void permutation();
  46. void keygen();
  47. char * Encrypt(char *);
  48. char * Decrypt(char *);
  49. };
  50. void Des::IP() //Initial Permutation
  51. {
  52. int k=58,i;
  53. for(i=0;i<32;i++)
  54. {
  55. ip[i]=total[k-1];
  56. if(k-8>0) k=k-8;
  57. else k=k+58;
  58. }
  59. k=57;
  60. for( i=32;i<64;i++)
  61. {
  62. ip[i]=total[k-1];
  63. if(k-8>0) k=k-8;
  64. else k=k+58;
  65. }
  66. }
  67. void Des::PermChoice1() //Permutation Choice-1
  68. {
  69. int k=57,i;
  70. for(i=0;i<28;i++)
  71. {
  72. pc1[i]=key[k-1];
  73. if(k-8>0) k=k-8;
  74. else k=k+57;
  75. }
  76. k=63;
  77. for( i=28;i<52;i++)
  78. {
  79. pc1[i]=key[k-1];
  80. if(k-8>0) k=k-8;
  81. else k=k+55;
  82. }
  83. k=28;
  84. for(i=52;i<56;i++)
  85. {
  86. pc1[i]=key[k-1];
  87. k=k-8;
  88. }
  89. }

This is a program for Encryption and Decryption
This program uses the Simple Data Encryption Standard (SDES) Algorithm.
This Algo takes 8-bits of plaintext at a time and produces 8-bits of ciphertext.
It uses 10-bits of key for Encryption and Decryption.

  • Function applies a 48-bit key to the rightmost 32 bits (R I−1) to produce a 32-bit output. This function is made up of four sections: an expansion D-box, a whitener (that adds key), a group of S-boxes, and a straight D-box as shown in Fig. Expansion D-box Since R I−1 is a 32-bit input and K I is a 48-bit key, we fi rst need to expand.
  • You can tie the key to the hardware serial IDS (microsoft does or used to do this, change 2-3 pieces of hardware and its invalid). I don't know how they do it but it may be a library you can get if its a windows program. If you get extra serious (software worth thousands of dollars) you can force a hardware key (usb device needed to run software).
  • // See Global Unlock Sample for sample code. CkRsa rsa; // Generate a 1024-bit key. Chilkat RSA supports // key sizes ranging from 512 bits to 4096 bits. // Note: Starting in Chilkat v9.5.0.49, RSA key sizes can be up to 8192 bits. // It takes a considerable amount of time and processing power to generate // an 8192-bit key. Bool success = rsa.
  • PC2 is a selection permutation. You might notice that the first 24 bits of the selected Key are from the C Register (CD(1 to 28)) and the second 24 bits are from the D register (CD(29 to 56)). The order of the selected Key bits in each have is non-linear. The left portion of the table is recognizable as PC2 from the Digital Encryption Standard.
  • I'm writing simple code in C using OpenSSL to generate valid bitcoin address - private key pair. I'm using this snippet to generate public key from given hex-form private key: #include <stdi.
9,390 Views

S-des Key Generation Code In C 2b 2b 1b

I have extreme interest in learning new Technologies.
Currently working in IPTV Domain. Its cool!

We rearrange 32bit text by following the order of that matrix. See the matrix in below code After expansion permutation we have to XOR the output 48bit with a 48bit sub key. Let see how that 48bit sub key generating from 64bit original key. Permutated Choice 1: Initially we take a 64 bit key and then apply to permutated choice 1.

sir..Can I get explaination for each line please..

Thank you in advance

S-des Key Generation Code In C%2b%2b
Editedby Udupa

@Sri_2 Auto tune plug in for mixcraft.

S-des Key Generation Code In C 2b 2b 4

It's C language.
See the fragment with the includes. typical for C.
Don't know if it's ansi-C or C++ or an other 'version' of C..

S-des Key Generation Code In C%2b%2b

Moxa uport 1450 driver. A cool program for sure, but I always submit to the observation I have read in a practical crypto book, 'Don't roll your own encryption' I don't know much about this crypto standard, but when people roll their own encryption they tend to make mistakes regaurdless of how well they try. There shouldy be crypto analysts, and mathemeticians, and whole scores of other people involved in implementing a crypto standard. More eyes take care of the problems. Subtle problems are always the bane of crypto programs.

S-des Key Generation Code In C 2b 2b 1

We're a friendly, industry-focused community of1.20 million developers, IT pros, digital marketers,and technology enthusiasts learning and sharing knowledge.