JAVA

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;

class AES256JavaPhp{
        public static void main(String[] args) throws Exception {
                Base64 base64 = new Base64();
                Cipher ciper = Cipher.getInstance("AES/CBC/PKCS5Padding");
                SecretKeySpec key = new
                          SecretKeySpec("PasswordPassword".getBytes("UTF-8"),"AES");
                IvParameterSpec iv = new IvParameterSpec
                      ("dynamic@dynamic@".getBytes("UTF-8"),0,ciper.getBlockSize());
            //Encrypt
                ciper.init(Cipher.ENCRYPT_MODE, key,iv);
                byte[] encryptedCiperBytes = base64.encode
                                              ((ciper.doFinal("Hello".getBytes())));
                System.out.println("Ciper : "+new String(encryptedCiperBytes));
            //Decrypt
                ciper.init(Cipher.DECRYPT_MODE, key,iv);    
                byte[] text = ciper.doFinal(base64.decode(encryptedCiperBytes));
                System.out.println("Decrypt text : "+new String(text));
          }
    }

Salida de Java:

Ciper : KpgzpzCRU7mTKZePpPlEvA==
Decrypt text : Hello

PHP

<?php>    
        $cipherText = encrypt("Hello", 'aes-256-cbc');
        exit();

        function encrypt($data, $algo)
        {
            $key = 'PasswordPassword';
            //$iv = random_bytes(openssl_cipher_iv_length($algo));
            $iv = 'dynamic@dynamic@';
            $cipherText = openssl_encrypt(
                    $data,
                    $algo,
                    $key,
                    OPENSSL_RAW_DATA,
                    $iv
                );
        $cipherText = base64_encode($cipherText);
        printData("Ciper Text : $cipherText");

        $cipherText = base64_decode($cipherText);
        $plaintext = openssl_decrypt(
                    $cipherText,
                    $algo,
                    $key,
                    OPENSSL_RAW_DATA,
                    $iv
                );
        printData("Plain Text after decryption : $plaintext");
        }

        function printData($obj)
        {
            print_r($obj);
        }
?>

Salida PHP:

Ciper Text : ef/ENVlBn9QBFlkvoN7P2Q==
Plain Text after decryption : Hello

Las cifras resultantes son diferentes, a pesar de que usan la misma clave y IV. ¿Cómo es esto posible?