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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. class self_synchronizing_scrambler
  5. {
  6. 	unsigned char key;
  7. 	unsigned char shift_register;
  8.  
  9. 	bool pickbit(const unsigned char val, const short index)
  10. 	{
  11. 		return ((val >> index)%2);
  12. 	}
  13.  
  14. 	public:
  15. 	self_synchronizing_scrambler() {}
  16.  
  17. 	self_synchronizing_scrambler(unsigned char key, unsigned char shift_register)
  18. 	{
  19. 		this->key = key;
  20. 		this->shift_register = shift_register;
  21. 	}
  22.  
  23. 	void assign_key(unsigned char key) {this->key = key;}
  24. 	void assign_register(unsigned char shift_register) {this->shift_register = shift_register;}
  25.  
  26. 	unsigned char key_value() {return key;}
  27. 	unsigned char register_value() {return shift_register;}
  28.  
  29. 	void scramble(unsigned char &letter)
  30. 	{
  31. 		unsigned char output = 0;
  32. 		for (unsigned char i = 0; i < 8; ++i)
  33. 		{
  34. 			bool newbit = pickbit(letter, 7-i);
  35. 			for (unsigned char j = 0; j < 8; ++j)
  36. 			{
  37. 				newbit ^= pickbit(this->key, 7-j) & pickbit(this->shift_register, 7-j);
  38. 			}
  39. 			output ^= (newbit << (7-i));
  40.  
  41. 			key = (key >> 1) + (newbit << 7);
  42. 		}
  43. 		letter = output;
  44. 	}
  45.  
  46. 	void descramble(unsigned char &letter)
  47. 	{
  48. 		unsigned char output = 0;
  49. 		for(unsigned char i = 0; i < 8; ++i)
  50. 		{
  51. 			bool oldbit = pickbit(letter, 7-i), scrambit = 0;
  52. 			for(unsigned char j = 0; j < 8; ++j)
  53. 			{
  54. 				scrambit ^= pickbit(this->key, 7-j) & pickbit(this->shift_register, 7-j);
  55. 			}
  56. 			output ^= ((scrambit^oldbit) << (7-i));
  57.  
  58. 			key = (key >> 1) + (oldbit << 7);
  59. 		}
  60. 		letter = output;
  61. 	}
  62. };
  63.  
  64. int main()
  65. {
  66. 	self_synchronizing_scrambler A(5,17);
  67. 	unsigned short scrambled;
  68. 	unsigned char output;
  69.  
  70. 	while (cin >> hex >> scrambled)
  71. 	{
  72. 		output = scrambled;
  73. 		A.descramble(output);
  74. 		cout << output;
  75. 	}
  76.  
  77. 	return 0;
  78. }
Success #stdin #stdout 0s 4264KB
comments (?)
stdin
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ec 49 a0 c9 72 75 43 13 55 66 28 80 e7 ed d2 75 b7 bf 69 93 c7 df 4e d0 be 3f b1 de 5c f6 ea 6c 94 f5 8d 1f 86 80 aa 74 5e c7 9e 17 2 47 41 76 7c d4 a1
stdout
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Base, base, it’s cheeseburger 1. Can you hear me?
https://ideone.com/nihBh2
Self Synchronizing Descrambler (C++)
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
secret

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