Passport decryption functions written by PHP

Source: Internet
Author: User
  1. /**

  2. * Passport decryption function
  3. *
  4. * @param string of strings after encryption
  5. * @param string private key (for decryption and encryption)
  6. *
  7. * Results of @return string strings being decrypted by private key
  8. */
  9. function Passport_decrypt ($txt, $key) {

  10. The result of the $txt is that the encrypted string is Base64 decoded and then, together with the private key,

  11. return value after processing by the Passport_key () function
  12. $txt = Passport_key (Base64_decode ($txt), $key);

  13. Variable initialization

  14. $tmp = ";

  15. For loop, $i starting from 0 to an integer less than $txt string length

  16. for ($i = 0; $i < strlen ($txt); $i + +) {
  17. $tmp string adds a bit to the end of the $txt $i bit,
  18. With $txt $i + 1-bit XOR. Then $i = $i + 1
  19. $tmp. = $txt [$i] ^ $txt [+ + $i];
  20. }

  21. Returns the value of the $tmp as a result

  22. return $tmp;

  23. }

  24. /**

  25. * Passport Key processing function
  26. *
  27. * @param string to be encrypted or to be decrypted
  28. * @param string private key (for decryption and encryption)
  29. *
  30. * @return The key after string processing
  31. */
  32. function Passport_key ($txt, $encrypt _key) {

  33. Assigns $encrypt _key to $encrypt _key by MD5 ()

  34. $encrypt _key = MD5 ($encrypt _key);

  35. Variable initialization

  36. $ctr = 0;
  37. $tmp = ";

  38. For loop, $i starting from 0 to an integer less than $txt string length

  39. for ($i = 0; $i < strlen ($txt); $i + +) {
  40. $ctr zeroed If $ctr = $encrypt the length of the _key
  41. $ctr = $ctr = = strlen ($encrypt _key)? 0: $ctr;
  42. $tmp string adds a bit to the end of the $txt $i bit,
  43. With $encrypt _key $ctr + 1-bit XOR. Then $ctr = $ctr + 1
  44. $tmp. = $txt [$i] ^ $encrypt _key[$ctr + +];
  45. }

  46. Returns the value of the $tmp as a result

  47. return $tmp;
  48. }
  49. ?>

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