Need Java equvalent for 3DES decryption of PHP code
-
26-05-2021 - |
سؤال
This is the PHP code I have.
function decrypt($s_input, $s_key, $s_iv) {
$s_decrypted = pack("H*" , $s_input); // Hex to binary
$s_decrypted = mcrypt_decrypt (MCRYPT_3DES, $s_key, $s_decrypted, MCRYPT_MODE_CBC, $s_iv); // 3des decryption
return $s_decrypted;
}
echo encrypt('c37551bb77f741d0bcdc16497b4f97b1','123456781234567812345678','12345678' );
what it basically does is to decrypt a 3des encrypted string (first it convert the hex string to binary using pack function and then does the actual decryption).
This perfectly works in PHP-4 and prints the "Hello World" message.
However, if I run the equivalent java code (jdk 1.6), it prints garbage output as - ¬ªmjV=7xl_ÓÄ^›*?.
Can someone help to troubleshoot this? Why Java is not properly decrypting the hex string.
private static String decrypt(String inputStr, String keyStr, String ivStr) throws Exception {
IvParameterSpec iv = new IvParameterSpec(ivStr.getBytes());
SecretKeySpec key = new SecretKeySpec(keyStr.getBytes(), "DESede");
inputStr = hexToString(inputStr, 2);
Cipher cipher = Cipher.getInstance("DESede/CBC/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, key, iv);
byte[] decrypted = cipher.doFinal(inputStr.getBytes());
return new String(decrypted);
}
private static String hexToString(String input, int groupLength) {
StringBuilder sb = new StringBuilder(input.length() / groupLength);
for (int i = 0; i < input.length() - groupLength + 1; i += groupLength) {
String hex = input.substring(i, i + groupLength);
sb.append((char) Integer.parseInt(hex, 16));
}
return sb.toString();
}
public static void main(String[] args) throws Exception {
String decryptSignature = decrypt("c37551bb77f741d0bcdc16497b4f97b1", "123456781234567812345678", "12345678");
System.out.println(decryptSignature);
}
المحلول
There are a few things you should check. You might find Encryption using AES-128 in Java to be of some assistance. There could be issues with differences between how you are handling keys in the PHP and Java code. Calling getBytes()
on a String
in Java without an encoding is almost always a bad idea. Plus the padding used could be a problem. From what I've seen PHP pads with null
characters by default, which does not correspond to NoPadding
in Java. Finally, the hexToString
method should return a byte[]
instead of a String
. Add the result of calling Integer.parseInt(hex, 16)
into an array:
byte[] results = new byte[input.length() / groupLength];
...
//inside the loop
results[i / groupLength] = (byte) Integer.parseInt(hex, 16);
...
return results;