SV.WEAK.KEYS.DH

Insufficient key length in Cryptographic Algorithm

Klocwork reports a SV.WEAK.KEYS.DH defect when the DH cryptographic algorithm is used with a key that is of insufficient size.

Vulnerability and risk

Small key size can lead to algorithm breaks that can then lead to the leakage of sensitive data. Algorithms need to be robust against the powerful computing techniques that are used to perform brute force attacks.

Mitigation and prevention

Avoid implementing DH algorithms with keys that are less than 2048 bits.

Vulnerable code example

Copy
import java.security.KeyPairGenerator;
 
class KeyGenDHTest {
  public static void main(String[] args) {
    KeyPairGenerator generatorDH = KeyPairGenerator.getInstance("DH");
    generatorDH.initialize(1024);  // SV.WEAK.KEYS.DH (!)
  }
}

Klocwork reports an SV.WEAK.KEYS.DH defect on line 6, indicating, "Cryptographic Algorithm uses key less than 2048 bits". A DH algorithm needs a key that is at least 2048 bits.

Fixed code example

Copy
import java.security.KeyPairGenerator;
 
class KeyGenDHTest {
  public static void main(String[] args) {
    KeyPairGenerator generatorDH = KeyPairGenerator.getInstance("DH");
    generatorDH.initialize(2048);  // no SV.WEAK.KEYS.DH
  }
}

Klocwork no longer reports a defect because the DH algorithm uses a key that is 2048 bits.

Security training

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