Passport decryption function written in php

Source: Internet
Author: User
Passport decryption function written in php

  1. /**

  2. * Passport decryption function
  3. *
  4. * @ Param string the encrypted string
  5. * @ Param string private key (used for decryption and encryption)
  6. *
  7. * @ Return string result after private key decryption
  8. */
  9. Function passport_decrypt ($ txt, $ key ){

  10. // $ Txt results in base64 decoding of the encrypted string, and then together with the private key,

  11. // Return value after passport_key () function processing
  12. $ Txt = passport_key (base64_decode ($ txt), $ key );

  13. // Variable initialization

  14. $ Tmp = '';

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

  16. For ($ I = 0; $ I <strlen ($ txt); $ I ++ ){
  17. // $ Tmp adds a bit at the end of the string, whose content is the $ I bit of $ txt,
  18. // It is the same as the $ I + 1 bits in $ txt. Then $ I = $ I + 1
  19. $ Tmp. = $ txt [$ I] ^ $ txt [++ $ I];
  20. }

  21. // Return the value of $ tmp as the result

  22. Return $ tmp;

  23. }

  24. /**

  25. * Passport key processing function
  26. *
  27. * @ Param string the string to be encrypted or to be decrypted
  28. * @ Param string private key (used for decryption and encryption)
  29. *
  30. * @ Return string the processed key
  31. */
  32. Function passport_key ($ txt, $ encrypt_key ){

  33. // Assign $ encrypt_key to the value of $ encrypt_key after md5 ()

  34. $ Encrypt_key = md5 ($ encrypt_key );

  35. // Variable initialization

  36. $ Ctr = 0;
  37. $ Tmp = '';

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

  39. For ($ I = 0; $ I <strlen ($ txt); $ I ++ ){
  40. // If $ ctr = $ encrypt_key length, $ ctr is cleared.
  41. $ Ctr = strlen ($ encrypt_key )? 0: $ ctr;
  42. // $ Tmp adds a bit at the end of the string, whose content is the $ I bit of $ txt,
  43. // It is the same or as the $ ctr + 1 of $ encrypt_key. Then $ ctr = $ ctr + 1
  44. $ Tmp. = $ txt [$ I] ^ $ encrypt_key [$ ctr ++];
  45. }

  46. // Return the value of $ tmp as the result

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

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