CodeQL documentation

Use of a cryptographic algorithm with insufficient key size

ID: java/insufficient-key-size
Kind: path-problem
Security severity: 7.5
Severity: warning
Precision: high
   - security
   - external/cwe/cwe-326
Query suites:
   - java-code-scanning.qls
   - java-security-extended.qls
   - java-security-and-quality.qls

Click to see the query in the CodeQL repository

Modern encryption relies on the computational infeasibility of breaking a cipher and decoding its message without the key. As computational power increases, the ability to break ciphers grows, and key sizes need to become larger as a result. Cryptographic algorithms that use too small of a key size are vulnerable to brute force attacks, which can reveal sensitive data.


Use a key of the recommended size or larger. The key size should be at least 128 bits for AES encryption, 256 bits for elliptic-curve cryptography (ECC), and 2048 bits for RSA, DSA, or DH encryption.


The following code uses cryptographic algorithms with insufficient key sizes.

    KeyPairGenerator keyPairGen1 = KeyPairGenerator.getInstance("RSA");
    keyPairGen1.initialize(1024); // BAD: Key size is less than 2048

    KeyPairGenerator keyPairGen2 = KeyPairGenerator.getInstance("DSA");
    keyPairGen2.initialize(1024); // BAD: Key size is less than 2048

    KeyPairGenerator keyPairGen3 = KeyPairGenerator.getInstance("DH");
    keyPairGen3.initialize(1024); // BAD: Key size is less than 2048

    KeyPairGenerator keyPairGen4 = KeyPairGenerator.getInstance("EC");
    ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp112r1"); // BAD: Key size is less than 256

    KeyGenerator keyGen = KeyGenerator.getInstance("AES");
    keyGen.init(64); // BAD: Key size is less than 128

To fix the code, change the key sizes to be the recommended size or larger for each algorithm.


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