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  1. #1
    Akirien is offline Member
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    Default Uncompilable source code - Erroneous sym type: Utils.createFixedRandom?

    Hello there. I got this code for El Gamal algorithm but it's not working. The error is as stated in title.

    Java Code:
    package crypto;
    
    import java.security.AlgorithmParameterGenerator;
    import java.security.AlgorithmParameters;
    import java.security.Key;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.SecureRandom;
    import java.security.spec.AlgorithmParameterSpec;
    import java.util.*; 
    import javax.crypto.Cipher;
    import javax.crypto.spec.DHParameterSpec;
    
    /**
     * El Gamal example with random key generation.
     */
    public class Crypto
    {
        public static void main(String[] args) throws Exception
        {
            byte[]           input = new byte[] { (byte)0xbe, (byte)0xef };
            Cipher           cipher = Cipher.getInstance(
                                                 "ElGamal/None/NoPadding", "BC");
            SecureRandom     random = Utils.createFixedRandom();
    
            // create the parameters
            AlgorithmParameterGenerator apg = AlgorithmParameterGenerator.getInstance(
                                                                     "ElGamal", "BC");
    
            apg.init(256, random);
    
            AlgorithmParameters     params = apg.generateParameters();
            AlgorithmParameterSpec  dhSpec = params.getParameterSpec(
                                                                DHParameterSpec.class);
    
            // create the keys
            KeyPairGenerator generator = KeyPairGenerator.getInstance("ElGamal", "BC");
    
            generator.initialize(dhSpec, random);
    
            KeyPair          pair = generator.generateKeyPair();
            Key              pubKey = pair.getPublic();
            Key              privKey = pair.getPrivate();
    
            System.out.println("input : " + Utils.toHex(input));
    
            // encryption step
    
            cipher.init(Cipher.ENCRYPT_MODE, pubKey, random);
    
            byte[] cipherText = cipher.doFinal(input);
    
            System.out.println("cipher: " + Utils.toHex(cipherText));
    
            // decryption step
    
            cipher.init(Cipher.DECRYPT_MODE, privKey);
    
            byte[] plainText = cipher.doFinal(cipherText);
    
            System.out.println("plain : " + Utils.toHex(plainText));
        }
    }
    Thanks in advance :D

  2. #2
    Norm's Avatar
    Norm is offline Moderator
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    Default Re: Uncompilable source code - Erroneous sym type: Utils.createFixedRandom?

    Where is the Utils class defined? The compiler can not find its definition.
    Is it in a package that you need to import?

  3. #3
    Akirien is offline Member
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    Default Re: Uncompilable source code - Erroneous sym type: Utils.createFixedRandom?

    Quote Originally Posted by Norm View Post
    Where is the Utils class defined? The compiler can not find its definition.
    Is it in a package that you need to import?
    I dont know, I got this code from Beginning Cryptography for JAVA books. :(

  4. #4
    Tolls is offline Moderator
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    Default Re: Uncompilable source code - Erroneous sym type: Utils.createFixedRandom?

    Then I would check in that book and see whether there's a resources section or web link to code associated with the examples.

  5. #5
    Norm's Avatar
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    Default Re: Uncompilable source code - Erroneous sym type: Utils.createFixedRandom?

    If you do not have the definitions for that class, you will have to figure out if there is a similar class in the Java SE classes and change the code to use the Java SE class.

    Check the book's appendix or its website for the class's definition.

  6. #6
    DarrylBurke's Avatar
    DarrylBurke is offline Member
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    Default Re: Uncompilable source code - Erroneous sym type: Utils.createFixedRandom?

    Moving to New to Java. Inability to compile source code doesn't belong in Advanced Java.

    db
    If you're forever cleaning cobwebs, it's time to get rid of the spiders.

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