PHP/Utility Function/mcrypt enc get key size
Symmetric Decryption
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<?
srand((double)microtime( )*1000000 ); $td = mcrypt_module_open(MCRYPT_RIJNDAEL_256, "", MCRYPT_MODE_CFB, ""); $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND); $ks = mcrypt_enc_get_key_size($td); $key = substr(sha1("Your Secret Key Here"), 0, $ks); mcrypt_generic_init($td, $key, $iv); $ciphertext = mcrypt_generic($td, "This is very important data"); mcrypt_generic_deinit($td); mcrypt_generic_init($td, $key, $iv); $plaintext = mdecrypt_generic($td, $ciphertext); mcrypt_generic_deinit($td); mcrypt_module_close($td); print $iv . "\n"; print trim($ciphertext) . "\n"; print trim($plaintext) . "\n";
?>
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