Most of cryptographic systems require a sufficient key size to be robust against brute-force attacks.
NIST recommendations will be checked for these
use-cases:
Digital Signature Generation and Verification:
- p ≥ 2048 AND q ≥ 224 for DSA (
p is key length and q the modulus length)
- n ≥ 2048 for RSA (
n is the key length)
Key Agreement:
- p ≥ 2048 AND q ≥ 224 for DH and MQV
- n ≥ 224 for ECDH and ECMQV (Examples:
secp192r1 is a non-compliant curve (n < 224) but secp224k1 is
compliant (n >= 224))
Symmetric keys:
This rule will not raise issues for ciphers that are considered weak (no matter the key size) like DES, Blowfish.
Noncompliant Code Example
KeyPairGenerator keyPairGen1 = KeyPairGenerator.getInstance("RSA");
keyPairGen1.initialize(1024); // Noncompliant
KeyPairGenerator keyPairGen5 = KeyPairGenerator.getInstance("EC");
ECGenParameterSpec ecSpec1 = new ECGenParameterSpec("secp112r1"); // Noncompliant
keyPairGen5.initialize(ecSpec1);
KeyGenerator keyGen1 = KeyGenerator.getInstance("AES");
keyGen1.init(64); // Noncompliant
Compliant Solution
KeyPairGenerator keyPairGen6 = KeyPairGenerator.getInstance("RSA");
keyPairGen6.initialize(2048); // Compliant
KeyPairGenerator keyPairGen5 = KeyPairGenerator.getInstance("EC");
ECGenParameterSpec ecSpec10 = new ECGenParameterSpec("secp256r1"); // compliant
keyPairGen5.initialize(ecSpec10);
KeyGenerator keyGen2 = KeyGenerator.getInstance("AES");
keyGen2.init(128); // Compliant
See
