CryptoJs AES encryption and Java Decrypt

Question

CryptoJS AES encryption and Java AES decryption I came across the above solution. I tried changing hashing ago from md5 to SHA-256, but it doesnt work. gives my the following error:

javax.crypto.BadPaddingException: Given final block not properly padded. Such issues can arise if a bad key is used during decryption.

Is there anything i need to change in the helper function

Answer 1

I used the answer in CryptoJS AES encryption and Java AES decryption as basis for a program that includes encryption and changes the MessageDigest from MD5 to SHA-256.

Running this program it sucessfully decrypts the encrypted data (as Base64-string in cipherText):

Changes: added encryption and using SHA-256 as hash algorithm
cipherText: AAAAAAAAAAAUUMNwaxNxbgvkWpqE+kfq0f3K/cQ6wwwiwFFsIBa8PXsoi0Z7dRhtNVurV1MbysOzNh9R9YMltSM/6en8e9JmEingdD3Rgp8=
The quick brown fox jumps over the lazy dog. 👻 👻

Running this program "stand alone" will work as expected but not as asked "encrypt in CryptoJS and decrypt in Java". That's because the MD5-hashing is "built in" (or "hard-coded") in CryptoJS as already commented by @Topaco some hours ago (all credits to him). So in the end there is no other way as to use MD5 on Java-side as CryptoJS uses it as MessageDigest. Maybe there is another crypto-library available for JavaScript.

Here is my code:

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.util.Arrays;
import java.util.Base64;

public class MainOrgSha256WithEncryption {
    public static void main(String[] args) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        System.out.println("https://stackoverflow.com/questions/41432896/cryptojs-aes-encryption-and-java-aes-decryption");
        System.out.println("Changes: added encryption and using SHA-256 as hash algorithm");

        String secret = "René Über";
        String plainText = "The quick brown fox jumps over the lazy dog. \uD83D\uDC7B \uD83D\uDC7B";
        // generate random salt
        SecureRandom secureRandom = new SecureRandom();
        byte[] saltDataEncryption = new byte[8];
        secureRandom.nextBytes(saltDataEncryption);
        // changed MessageDigest from MD5 to SHA-256
        MessageDigest md5 = MessageDigest.getInstance("SHA-256");
        //MessageDigest md5 = MessageDigest.getInstance("MD5");
        final byte[][] keyAndIVEncryption = GenerateKeyAndIV(32, 16, 1, saltDataEncryption, secret.getBytes(StandardCharsets.UTF_8), md5);
        SecretKeySpec keyEncryption = new SecretKeySpec(keyAndIVEncryption[0], "AES");
        IvParameterSpec ivEncryption = new IvParameterSpec(keyAndIVEncryption[1]);
        // encryption
        Cipher aesCBCEncryption = Cipher.getInstance("AES/CBC/PKCS5Padding");
        aesCBCEncryption.init(Cipher.ENCRYPT_MODE, keyEncryption, ivEncryption);
        byte[] cipherTextEncryption = aesCBCEncryption.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
        // concate 8 zero bytes + salt + cipherTextEncryption
        int arrayLength = 8 + saltDataEncryption.length + cipherTextEncryption.length;
        byte[] cipherTextEncryptionComplete = new byte[arrayLength];
        System.arraycopy(saltDataEncryption, 0, cipherTextEncryptionComplete, 8, saltDataEncryption.length);
        System.arraycopy(cipherTextEncryption, 0, cipherTextEncryptionComplete, 16, cipherTextEncryption.length);
        String cipherTextBase64 = Base64.getEncoder().encodeToString(cipherTextEncryptionComplete);
        // now we are using the new cipherTextBase64 as input for the decryption
        String cipherText = cipherTextBase64;
        System.out.println("cipherText: " + cipherText);

        // decryption
        byte[] cipherData = Base64.getDecoder().decode(cipherText);
        byte[] saltData = Arrays.copyOfRange(cipherData, 8, 16);

        final byte[][] keyAndIV = GenerateKeyAndIV(32, 16, 1, saltData, secret.getBytes(StandardCharsets.UTF_8), md5);
        SecretKeySpec key = new SecretKeySpec(keyAndIV[0], "AES");
        IvParameterSpec iv = new IvParameterSpec(keyAndIV[1]);

        byte[] encrypted = Arrays.copyOfRange(cipherData, 16, cipherData.length);
        Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");
        aesCBC.init(Cipher.DECRYPT_MODE, key, iv);
        byte[] decryptedData = aesCBC.doFinal(encrypted);
        String decryptedText = new String(decryptedData, StandardCharsets.UTF_8);

        System.out.println(decryptedText);
    }
    /**
     * Generates a key and an initialization vector (IV) with the given salt and password.
     * <p>
     * This method is equivalent to OpenSSL's EVP_BytesToKey function
     * (see https://github.com/openssl/openssl/blob/master/crypto/evp/evp_key.c).
     * By default, OpenSSL uses a single iteration, MD5 as the algorithm and UTF-8 encoded password data.
     * </p>
     * @param keyLength the length of the generated key (in bytes)
     * @param ivLength the length of the generated IV (in bytes)
     * @param iterations the number of digestion rounds
     * @param salt the salt data (8 bytes of data or <code>null</code>)
     * @param password the password data (optional)
     * @param md the message digest algorithm to use
     * @return an two-element array with the generated key and IV
     */
    public static byte[][] GenerateKeyAndIV(int keyLength, int ivLength, int iterations, byte[] salt, byte[] password, MessageDigest md) {

        int digestLength = md.getDigestLength();
        int requiredLength = (keyLength + ivLength + digestLength - 1) / digestLength * digestLength;
        byte[] generatedData = new byte[requiredLength];
        int generatedLength = 0;

        try {
            md.reset();

            // Repeat process until sufficient data has been generated
            while (generatedLength < keyLength + ivLength) {

                // Digest data (last digest if available, password data, salt if available)
                if (generatedLength > 0)
                    md.update(generatedData, generatedLength - digestLength, digestLength);
                md.update(password);
                if (salt != null)
                    md.update(salt, 0, 8);
                md.digest(generatedData, generatedLength, digestLength);

                // additional rounds
                for (int i = 1; i < iterations; i++) {
                    md.update(generatedData, generatedLength, digestLength);
                    md.digest(generatedData, generatedLength, digestLength);
                }

                generatedLength += digestLength;
            }

            // Copy key and IV into separate byte arrays
            byte[][] result = new byte[2][];
            result[0] = Arrays.copyOfRange(generatedData, 0, keyLength);
            if (ivLength > 0)
                result[1] = Arrays.copyOfRange(generatedData, keyLength, keyLength + ivLength);

            return result;

        } catch (DigestException e) {
            throw new RuntimeException(e);

        } finally {
            // Clean out temporary data
            Arrays.fill(generatedData, (byte)0);
        }
    }
}