Name: iiR10263 Date: 11/13/2003



The specification describes the following exceptions that are thrown
by javax.crypto.Cipher.init(int, Key):

Throws:
InvalidKeyException - if the given key is inappropriate for
initializing this cipher, or if this cipher is being initialized for
decryption and requires algorithm parameters that cannot be determined
from the given key, or if the given key has a keysize that exceeds the
maximum allowable keysize (as determined from the configured
jurisdiction policy files).

It seems that the implementation does not check if a key is too long.

Please find the code example that reproduses the situation below:

import java.io.PrintWriter;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.AlgorithmParameters;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
                                                               
public class e6 {
                                                               
    public static void main(String argv[]) {
        Key k;
        Cipher c;
        AlgorithmParameters params = null;
                                                               
        String alg = "PBEWITHMD5ANDDES";
        byte[] salt = {
            (byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
            (byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
        };
        int count = 20;
        String s = "My wonderfull password that is long enough.
            "Tra-la-la, let me sing a song";
                                                               
        try {
            int kl = Cipher.getMaxAllowedKeyLength(alg);
                                                               
            if (kl != Integer.MAX_VALUE) {
                int l = kl + 8;
                SecretKeyFactory skf =
                    SecretKeyFactory.getInstance(alg);
                                                               
                PBEKeySpec ks = new PBEKeySpec(s.toCharArray(),
                    count, l);
                                                               
                if (ks.getKeyLength() != l) {
                    System.out.println("The generated key will
                        "strange length (not " + l + ")");
                } else {
                    System.out.println("The generated key will
                        "have length " + l);
                }
                                                               
                // PBE algorithm is symmetric.
                k = skf.generateSecret(ks);
                                                               
                c = Cipher.getInstance(alg);
                                                               
                try {
                    c.init(Cipher.ENCRYPT_MODE, k);
                    System.out.println("Where is my exception?"
                } catch (InvalidKeyException e) {
                }
            }
        } catch (Exception e) {
            e.printStackTrace(System.out);
        }
    }
}
Test output:
The generated key will have length 136
Where is my exception?

The situation is the same for all other algorithms.

java full version "1.5.0-beta-b26"

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