CODEWITHSUNDEEP
javasecuritycryptographyjceelliptic-curve
Shakeeb Manjeri
Shakeeb Manjeri

Reputation: 130

Invalid key exception when doing elliptical curve cryptography

I got this error when I did elliptical curve cryptography using flexyprovider. I received an InvalidKeyException but I can't figure out how to solve it:

Exception in thread "main" java.security.InvalidKeyException: Illegal key size
at javax.crypto.Cipher.checkCryptoPerm(Cipher.java:1024)
at javax.crypto.Cipher.init(Cipher.java:1345)
at javax.crypto.Cipher.init(Cipher.java:1282)
at ExampleECIES.main(ExampleECIES.java:43)

This is my code 

public class ExampleECIES {

    public static void main(String[] args) throws Exception {

    Security.addProvider(new FlexiCoreProvider());
    Security.addProvider(new FlexiECProvider());

    KeyPairGenerator kpg = KeyPairGenerator.getInstance("ECIES", "FlexiEC");

    CurveParams ecParams = new BrainpoolP160r1();

    kpg.initialize(ecParams, new SecureRandom());
    KeyPair keyPair = kpg.generateKeyPair();
    PublicKey pubKey = keyPair.getPublic();
    PrivateKey privKey = keyPair.getPrivate();

    // Encrypt

    Cipher cipher = Cipher.getInstance("ECIES", "FlexiEC");

    IESParameterSpec iesParams = new IESParameterSpec("AES128_CBC",
        "HmacSHA1", null, null);
    System.out.println(iesParams);
    cipher.init(Cipher.ENCRYPT_MODE, pubKey, iesParams);

    String cleartextFile = "cleartext.txt";
    String ciphertextFile = "ciphertextECIES.txt";

    byte[] block = new byte[64];
    FileInputStream fis = new FileInputStream(cleartextFile);
    FileOutputStream fos = new FileOutputStream(ciphertextFile);
    CipherOutputStream cos = new CipherOutputStream(fos, cipher);

    int i;
    while ((i = fis.read(block)) != -1) {
        cos.write(block, 0, i);
    }
    cos.close();

    // Decrypt

    String cleartextAgainFile = "cleartextAgainECIES.txt";

    cipher.init(Cipher.DECRYPT_MODE, privKey, iesParams);

    fis = new FileInputStream(ciphertextFile);
    CipherInputStream cis = new CipherInputStream(fis, cipher);
    fos = new FileOutputStream(cleartextAgainFile);

    while ((i = cis.read(block)) != -1) {
        fos.write(block, 0, i);
    }
    fos.close();
    }

}

Can anyone please help me? I'm using JDK version 1.7.0_25.

Upvotes: 1

Views: 724

Answers (1)

Daniel
Daniel

Reputation: 3010

I had the same problem when looking at the same example. I solved it with this answer.

Root Cause :

There are key size restrictions with the default JDK comes with - which limits it to 128. If your security policy uses a key size larger than this - then the exception is thrown.

Solution :

You need to patch your JDK with Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files.

Instructions on how to download JCE Policy files

src: java.security.InvalidKeyException: Illegal key size or default parameters

Upvotes: 2

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