CodeQL documentation

Use of a potentially broken or risky cryptographic algorithm

ID: java/potentially-weak-cryptographic-algorithm
Kind: path-problem
Severity: warning
Precision: medium
   - security
   - external/cwe/cwe-327
Query suites:
   - java-security-extended.qls
   - java-security-and-quality.qls

Click to see the query in the CodeQL repository

Using broken or weak cryptographic algorithms can leave data vulnerable to being decrypted.

Many cryptographic algorithms provided by cryptography libraries are known to be weak, or flawed. Using such an algorithm means that an attacker may be able to easily decrypt the encrypted data.


Ensure that you use a strong, modern cryptographic algorithm. Use at least AES-128 or RSA-2048. Do not use the ECB encryption mode since it is vulnerable to replay and other attacks.


The following code shows an example of using a java Cipher to encrypt some data. When creating a Cipher instance, you must specify the encryption algorithm to use. The first example uses DES, which is an older algorithm that is now considered weak. The second example uses AES, which is a strong modern algorithm.

// BAD: DES is a weak algorithm 
Cipher des = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);

byte[] encrypted = cipher.doFinal(input.getBytes("UTF-8"));

// ...

// GOOD: AES is a strong algorithm
Cipher des = Cipher.getInstance("AES");

// ...