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Insecure encryption algorithm - Blowfish

Need​

Secure encryption algorithm for protecting sensitive information

Context​

  • Usage of Java for building robust and scalable applications
  • Usage of javax.crypto.Cipher for cryptographic operations
  • Usage of javax.crypto.spec.SecretKeySpec for generating secret keys in cryptography

Description​

Non compliant code​

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

public class BlowfishEncryption {
    private static String algorithm = "Blowfish";
    private static byte[] keyValue;

    public BlowfishEncryption(String key) {
        keyValue = key.getBytes();
    }

    public String encrypt(String dataToEncrypt) throws Exception {
        SecretKeySpec key = new SecretKeySpec(keyValue, algorithm);
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] encryptedData = cipher.doFinal(dataToEncrypt.getBytes());
        return new String(encryptedData);
    }

    public String decrypt(String encryptedData) throws Exception {
        SecretKeySpec key = new SecretKeySpec(keyValue, algorithm);
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] decryptedData = cipher.doFinal(encryptedData.getBytes());
        return new String(decryptedData);
    }
}

The above code defines a class named BlowfishEncryption that uses the Blowfish encryption algorithm for encrypting and decrypting data. The encryption key is passed as a string to the constructor of the BlowfishEncryption class, which then converts it to a byte array and stores it in the keyValue field.

The encrypt method takes a string to be encrypted, creates a SecretKeySpec from the keyValue, and then uses a Cipher instance to encrypt the data. The encrypted data is then returned as a string.

Similarly, the decrypt method takes an encrypted string, creates a SecretKeySpec from the keyValue, and then uses a Cipher instance to decrypt the data. The decrypted data is then returned as a string.

The vulnerability in this code lies in the use of the Blowfish encryption algorithm, which is considered insecure. The Blowfish algorithm is susceptible to attacks such as birthday attacks, which exploit the fact that the probability of a collision (two inputs producing the same output) increases quadratically with the number of inputs, and is therefore not suitable for use in a secure context.

Steps​

  • Replace the insecure encryption algorithm (Blowfish) with a more secure algorithm.
  • Use a strong and secure encryption algorithm such as AES (Advanced Encryption Standard).
  • Ensure that the encryption algorithm used is recommended by security experts and has undergone thorough testing.
  • Update the code to use the recommended encryption algorithm.
  • Generate a strong and random encryption key.
  • Store the encryption key securely, such as in a secure key management system.
  • Avoid hardcoding the encryption key in the code.
  • Consider using a key derivation function to derive the encryption key from a user-provided password.
  • Implement proper key management practices, such as regularly rotating the encryption key.
  • Ensure that the encryption and decryption operations are performed securely and without any potential vulnerabilities.
  • Follow best practices for encryption, such as using authenticated encryption modes and properly handling padding.
  • Regularly review and update the encryption implementation to address any new vulnerabilities or weaknesses that may be discovered.

Compliant code​

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.KeyGenerator;
import java.security.SecureRandom;

public class AESEncryption {
    private static String algorithm = "AES";
    private static byte[] keyValue;

    public AESEncryption(String key) throws Exception {
        SecureRandom secureRandom = new SecureRandom();
        KeyGenerator keyGenerator = KeyGenerator.getInstance(algorithm);
        keyGenerator.init(256, secureRandom);
        keyValue = keyGenerator.generateKey().getEncoded();
    }

    public String encrypt(String dataToEncrypt) throws Exception {
        SecretKeySpec key = new SecretKeySpec(keyValue, algorithm);
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] encryptedData = cipher.doFinal(dataToEncrypt.getBytes());
        return new String(encryptedData);
    }

    public String decrypt(String encryptedData) throws Exception {
        SecretKeySpec key = new SecretKeySpec(keyValue, algorithm);
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] decryptedData = cipher.doFinal(encryptedData.getBytes());
        return new String(decryptedData);
    }
}

The original code was using the Blowfish encryption algorithm, which is considered insecure. The updated code now uses the AES (Advanced Encryption Standard) algorithm, which is currently the industry standard for secure encryption.

In the constructor of the AESEncryption class, a new encryption key is generated each time an instance of the class is created. This key is generated using a KeyGenerator initialized with a SecureRandom object, which ensures that the key is strong and random.

The encrypt and decrypt methods have been updated to use the AES algorithm. The Cipher object is initialized with the AES key, and the encryption and decryption operations are performed using this key.

The encryption key is stored in the keyValue byte array. This key should be stored securely, such as in a secure key management system, and should not be hardcoded in the code.

This code follows best practices for encryption, such as using a strong and secure encryption algorithm, generating a strong and random encryption key, and performing the encryption and decryption operations securely. However, it is important to regularly review and update the encryption implementation to address any new vulnerabilities or weaknesses that may be discovered.

References​

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