本文实例讲述了PHP加密解密方法。分享给大家供大家参考，具体如下：

//加密

function string2secret($str)

{

$key = "123";

$td = mcrypt_module_open(MCRYPT_DES,'','ecb','');

$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);

$ks = mcrypt_enc_get_key_size($td);

$key = substr(md5($key), 0, $ks);

mcrypt_generic_init($td, $key, $iv);

$secret = mcrypt_generic($td, $str);

mcrypt_generic_deinit($td);

mcrypt_module_close($td);

return $secret;

}

//解密

function secret2string($sec)

{

$key = "123";

$td = mcrypt_module_open(MCRYPT_DES,'','ecb','');

$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);

$ks = mcrypt_enc_get_key_size($td);

$key = substr(md5($key), 0, $ks);

mcrypt_generic_init($td, $key, $iv);

$string = mdecrypt_generic($td, $sec);

mcrypt_generic_deinit($td);

mcrypt_module_close($td);

return trim($string);

}

echo secret2string(string2secret("11111111111111111"));

//显示结果是11111111111111111

echo '<br>'.string2secret("11111111111111111");

//显示乱码

echo '<br>';

//$string:要加密的字符串 $isEncrypt=true:加密 $isEncrypt=false:解密

function dencrypt($string, $isEncrypt = true, $key = "KEY_SPACE") {

if (!isset($string{0}) || !isset($key{0})) {

return false;

}

$dynKey = $isEncrypt ? hash('sha1', microtime(true)) : substr($string, 0, 40);

$fixedKey = hash('sha1', $key);

$dynKeyPart1 = substr($dynKey, 0, 20);

$dynKeyPart2 = substr($dynKey, 20);

$fixedKeyPart1 = substr($fixedKey, 0, 20);

$fixedKeyPart2 = substr($fixedKey, 20);

$key = hash('sha1', $dynKeyPart1 . $fixedKeyPart1 . $dynKeyPart2 . $fixedKeyPart2);

$string = $isEncrypt ? $fixedKeyPart1 . $string . $dynKeyPart2 : (isset($string{339}) ? gzuncompress(base64_decode(substr($string, 40))) : base64_decode(substr($string, 40)));

$n = 0;

$result = '';

$len = strlen($string);

for ($n = 0; $n < $len; $n++) {

$result .= chr(ord($string{$n}) ^ ord($key{$n % 40}));

}

return $isEncrypt ? $dynKey . str_replace('=', '', base64_encode($n > 299 ? gzcompress($result) : $result)) : substr($result, 20, -20);

}

echo strlen(dencrypt("12345678912345"));

希望本文所述对大家PHP程序设计有所帮助。