InvalidKeyException : Illegal Key Size - Java code throwing exception for encryption class - how to fix?

Question

I've been trying to get some working Java code to use for encrypting Paypal buttons. This is no easy task! Even when I get some code, from Paypal, I'm faced with errors..ugh..

So here is what I have so far, that I think will work eventually.

I downloaded the Java.zip file from Paypal's website. Within it are two classes - ClientSide.java and ButtonEncryption.java

The Problem - I'm getting an InvalidKeyException : Illegal key size error.

Questions
1) How do I resolve this issue? 2) What line of code is throwing the error?

C:\jakarta-tomcat\webapps\PlanB\WEB-INF\classes>java palmb.servlets.paypal.ButtonEncryption
java.io.IOException: exception decrypting data - java.security.InvalidKeyException: Illegal key size
        at org.bouncycastle.jce.provider.JDKPKCS12KeyStore.cryptData(Unknown Source)
        at org.bouncycastle.jce.provider.JDKPKCS12KeyStore.engineLoad(Unknown Source)
        at java.security.KeyStore.load(Unknown Source)
        at palmb.servlets.paypal.ClientSide.getButtonEncryptionValue(ClientSide.java:63)
        at palmb.servlets.paypal.ButtonEncryption.main(ButtonEncryption.java:81)

ClientSide class

package palmb.servlets.paypal;

import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.security.InvalidAlgorithmParameterException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertStore;
import java.security.cert.CertStoreException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.CollectionCertStoreParameters;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Enumeration;

import org.bouncycastle.cms.CMSEnvelopedData;
import org.bouncycastle.cms.CMSEnvelopedDataGenerator;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.CMSSignedDataGenerator;
import org.bouncycastle.openssl.PEMReader;
import org.bouncycastle.util.encoders.Base64;

/**
 */
public class ClientSide 
{
    private String  keyPath;
    private String  certPath;
    private String  paypalCertPath;
    private String  keyPass;

    public ClientSide( String keyPath, String certPath, String paypalCertPath, String keyPass )
    {
        this.keyPath = keyPath;
        this.certPath = certPath;
        this.paypalCertPath = paypalCertPath;
        this.keyPass = keyPass;
    }   

    public String getButtonEncryptionValue(String _data, String _privateKeyPath, String _certPath, String _payPalCertPath,
                                            String _keyPass) throws IOException,CertificateException,KeyStoreException,
                                            UnrecoverableKeyException,InvalidAlgorithmParameterException,NoSuchAlgorithmException,
                                            NoSuchProviderException,CertStoreException,CMSException {
        _data = _data.replace(',', '\n');
        CertificateFactory cf = CertificateFactory.getInstance("X509", "BC");

        // Read the Private Key
        KeyStore ks = KeyStore.getInstance("PKCS12", "BC");
        ks.load( new FileInputStream(_privateKeyPath), _keyPass.toCharArray() );

        String keyAlias = null;
        Enumeration aliases = ks.aliases();
        while (aliases.hasMoreElements()) {
            keyAlias = (String) aliases.nextElement();
        }

        PrivateKey privateKey = (PrivateKey) ks.getKey( keyAlias, _keyPass.toCharArray() );

        // Read the Certificate
        X509Certificate certificate = (X509Certificate) cf.generateCertificate( new FileInputStream(_certPath) );

        // Read the PayPal Cert
        X509Certificate payPalCert = (X509Certificate) cf.generateCertificate( new FileInputStream(_payPalCertPath) );

        // Create the Data
        byte[] data = _data.getBytes();

        // Sign the Data with my signing only key pair
        CMSSignedDataGenerator signedGenerator = new CMSSignedDataGenerator();

        signedGenerator.addSigner( privateKey, certificate, CMSSignedDataGenerator.DIGEST_SHA1 );

        ArrayList certList = new ArrayList();
        certList.add(certificate);
        CertStore certStore = CertStore.getInstance( "Collection", new CollectionCertStoreParameters(certList) );
        signedGenerator.addCertificatesAndCRLs(certStore);

        CMSProcessableByteArray cmsByteArray = new CMSProcessableByteArray(data);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        cmsByteArray.write(baos);
        System.out.println( "CMSProcessableByteArray contains [" + baos.toString() + "]" );

        CMSSignedData signedData = signedGenerator.generate(cmsByteArray, true, "BC");

        byte[] signed = signedData.getEncoded();

        CMSEnvelopedDataGenerator envGenerator = new CMSEnvelopedDataGenerator();
        envGenerator.addKeyTransRecipient(payPalCert);
        CMSEnvelopedData envData = envGenerator.generate( new CMSProcessableByteArray(signed),
                CMSEnvelopedDataGenerator.DES_EDE3_CBC, "BC" );

        byte[] pkcs7Bytes = envData.getEncoded();


        return new String( DERtoPEM(pkcs7Bytes, "PKCS7") );

    }

    public static byte[] DERtoPEM(byte[] bytes, String headfoot) 
    {
        ByteArrayOutputStream pemStream = new ByteArrayOutputStream();
        PrintWriter writer = new PrintWriter(pemStream);

        byte[] stringBytes = Base64.encode(bytes);

        System.out.println("Converting " + stringBytes.length + " bytes");

        String encoded = new String(stringBytes);

        if (headfoot != null) {
            writer.print("-----BEGIN " + headfoot + "-----\n");
        }

        // write 64 chars per line till done
        int i = 0;
        while ((i + 1) * 64 < encoded.length()) {
            writer.print(encoded.substring(i * 64, (i + 1) * 64));
            writer.print("\n");
            i++;
        }
        if (encoded.length() % 64 != 0) {
            writer.print(encoded.substring(i * 64)); // write remainder
            writer.print("\n");
        }
        if (headfoot != null) {
            writer.print("-----END " + headfoot + "-----\n");
        }
        writer.flush();
        return pemStream.toByteArray();
    }

}

ButtonEncryption class

package palmb.servlets.paypal;

//import com.paypal.crypto.sample.*;

import palmb.servlets.paypal.ClientSide;

import java.io.*;
import java.security.InvalidAlgorithmParameterException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertStoreException;
import java.security.cert.CertificateException;
import org.bouncycastle.cms.CMSException;

/**
 */
public class ButtonEncryption {


    //path to public cert
    private static String certPath = "C:/jakarta-tomcat/webapps/PlanB/Certs/public-cert.pem";

    //path to private key in PKCS12 format
    private static String keyPath = "C:/jakarta-tomcat/webapps/PlanB/Certs/my_pkcs12.p12";

    //path to Paypal's public cert
    private static String paypalCertPath = "C:/jakarta-tomcat/webapps/PlanB/Certs/paypal_cert_pem.txt";

    //private key password
    private static String keyPass = "password"; //will be replaced with actual password when compiled and executed

    //the button command, properties/parameters
    private static String cmdText = "cmd=_xclick\nbusiness=buyer@hotmail.com\nitem_name=vase\nitemprice=25.00";  //cmd=_xclick,business=sample@paypal.com,amount=1.00,currency_code=USD

    //output file for form code
    private static String output = "test.html";


    public static void main(String[] args) 
    {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); 


        String stage = "sandbox";

        try 
        {
            ClientSide client_side = new ClientSide( keyPath, certPath, paypalCertPath, keyPass );

            String result = client_side.getButtonEncryptionValue( cmdText, keyPath, certPath, paypalCertPath, keyPass );

            File outputFile = new File( output );
            if ( outputFile.exists() )
                outputFile.delete();

            if ( result != null && result != "")
            {
                try {        
                    OutputStream fout= new FileOutputStream( output );
                    OutputStream bout= new BufferedOutputStream(fout);
                    OutputStreamWriter out = new OutputStreamWriter(bout, "US-ASCII");

                    out.write( "<form action=\"https://www." );
                    out.write( stage );
                    out.write( "paypal.com/cgi-bin/webscr\" method=\"post\">" );  
                    out.write( "<input type=\"hidden\" name=\"cmd\" value=\"_s-xclick\">" );  ;
                    out.write( "<input type=\"image\" src=\"https://www." );
                    out.write( stage );
                    out.write( "paypal.com/en_US/i/btn/x-click-but23.gif\" border=\"0\" name=\"submit\" " );
                    out.write( "alt=\"Make payments with PayPal - it's fast, free and secure!\">" );
                    out.write( "<input type=\"hidden\" name=\"encrypted\" value=\"" );
                    out.write( result );
                    out.write( "\">" );
                    out.write( "</form>");

                    out.flush();  // Don't forget to flush!
                    out.close();
                  }
                  catch (UnsupportedEncodingException e) {
                    System.out.println(
                     "This VM does not support the ASCII character set."
                    );
                  }
                  catch (IOException e) {
                    System.out.println(e.getMessage());        
                  }
            }
        } 
        catch (NoSuchAlgorithmException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (NoSuchProviderException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (IOException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (CMSException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (CertificateException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (KeyStoreException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (UnrecoverableKeyException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (InvalidAlgorithmParameterException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (CertStoreException e) 
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Edited : info about keys/certificates

I generated the Private Key and Public Certificate with OpenSSL via the following commands.
Private Key
openssl genrsa -out private-key.pem 1024
Public Certificate
openssl req -new -key private-key.pem -x509 -days 1095 -out public-cert.pem
Created PKCS12 File
openssl pkcs12 -export -in public-cert.pem -inkey private-key.pem -out my_pkcs12.p12

Additionally, I had to download the Paypal Public Certificate from the Paypal website.

Edited - adding compilation warnings - BouncyCastle

C:\jakarta-tomcat\webapps\PlanB\WEB-INF\classes>javac .\palmb\servlets\paypal\ClientSide.java -Xlint
.\palmb\servlets\paypal\ClientSide.java:85: warning: [deprecation] addSigner(java.security.PrivateKey,java.security.cert.X509Certificate,java.lang.String) in org.bouncycastle.cms.CMSSignedDataGenerator has been deprecated
                signedGenerator.addSigner( privateKey, certificate, CMSSignedDat
aGenerator.DIGEST_SHA1 );
                               ^
.\palmb\servlets\paypal\ClientSide.java:88: warning: [unchecked] unchecked call
to add(E) as a member of the raw type java.util.ArrayList
                certList.add(certificate);
                            ^
.\palmb\servlets\paypal\ClientSide.java:90: warning: [deprecation] addCertificatesAndCRLs(java.security.cert.CertStore) in org.bouncycastle.cms.CMSSignedGenerat
or has been deprecated
                signedGenerator.addCertificatesAndCRLs(certStore);
                               ^
.\palmb\servlets\paypal\ClientSide.java:97: warning: [deprecation] generate(org.
bouncycastle.cms.CMSProcessable,boolean,java.lang.String) in org.bouncycastle.cm
s.CMSSignedDataGenerator has been deprecated
                CMSSignedData signedData = signedGenerator.generate(cmsByteArray, true, "BC");
                                                          ^
.\palmb\servlets\paypal\ClientSide.java:102: warning: [deprecation] addKeyTransR
ecipient(java.security.cert.X509Certificate) in org.bouncycastle.cms.CMSEnvelope
dGenerator has been deprecated
                envGenerator.addKeyTransRecipient(payPalCert);
                            ^
.\palmb\servlets\paypal\ClientSide.java:103: warning: [deprecation] generate(org.bouncycastle.cms.CMSProcessable,java.lang.String,java.lang.String) in org.bouncycastle.cms.CMSEnvelopedDataGenerator has been deprecated
                CMSEnvelopedData envData = envGenerator.generate( new CMSProcess
ableByteArray(signed),
                                                       ^
6 warnings

JCE policy file installation steps

These are the steps I took to installing the JCE Unlimited Strength Policy files:
1) Went to Java JCE Download Page on Oracle.
2) Extracted files from zip.
3) Placed local_policy.jar and US_export_policy.jar files in C:\Java\jdk1.6.0_22\jre\lib\security folder.
Note: C:\Java\jdk1.6.0_22 is set as %JAVA_HOME%
4) Updated system classpath to include location of jars.
Note: There are other files, that came with the JDK 1.6 within the security folder, including : java.policy, java.security, javaws.policy, trusted.libraries - but those probably have nothing to do with the JCE files, right?

---

Edit 6/23/2011 - results after further configuration

I went to Bouncy Castle page at http://www.bouncycastle.org/specifications.html#install
Scroll down to 5.0 Bouncy Castle Provider then read info under 5.1 Example. It makes mention of adding a parameter for the Bouncy Castle Provider to the java.security file. My file is under C:\Java\jdk1.6.0_22\jre\lib\security.

I added the following line to my file - security.provider.10=org.bouncycastle.jce.provider.BouncyCastleProvider

In addition, I discovered that I hadn't added the Bouncy Castle jars to the classpath, so I went ahead and did so.

Now after making these changes, recompiling and attempting to execute ClientSide.java I'm given the same exception : but maybe the focus should be on the part of the exception where it says this about bouncycastle provider -

at org.bouncycastle.jce.provider.JDKPKCS12KeyStore.cryptData(Unknown Source)
at org.bouncycastle.jce.provider.JDKPKCS12KeyStore.engineLoad(Unknown Source)

@PeteyB - I'm certain that I installed the policy files correctly. Based on what I've stated here, is there anything else you can suggest I try? Can you look at the Bouncy Castle site @ http://www.bouncycastle.org/specifications.html#install and see if there is something I'm missing?

Answer 1

So the problem must be with your JCE Unlimited Strength installation.

Be sure you overwrite the local_policy.jar and US_export_policy.jar in both your JDK's jdk1.6.0_25\jre\lib\security\ and in your JRE's lib\security\ folder.

In my case I would place the new .jars in:

C:\Program Files\Java\jdk1.6.0_25\jre\lib\security

and

C:\Program Files\Java\jre6\lib\security

---

If you are running Java 8 and you encounter this issue. Below steps should help!

Go to your JRE installation (e.g - jre1.8.0_181\lib\security\policy\unlimited) copy local_policy.jar and replace it with 'local_policy.jar' in your JDK installation directory (e.g - jdk1.8.0_141\jre\lib\security).

Answer 2

If you are still recieving the InvalidKeyException when running my AES encryption program with 256 bit keys, but not with 128 bit keys, it is because you have not installed the new policy JAR files correctly, and has nothing to do with BouncyCastle (which is also restrained by those policy files). Try uninstalling, then re-installing java and then replaceing the old jar's with the new unlimited strength ones. Other than that, I'm out of ideas, best of luck.

You can see the policy files themselves if you open up the lib/security/local_policy.jar and US_export_policy.jar files in winzip and look at the conatined *.policy files in notepad and make sure they look like this:

default_local.policy:

    // Country-specific policy file for countries with no limits on crypto strength.
grant {
    // There is no restriction to any algorithms.
    permission javax.crypto.CryptoAllPermission; 
};

default_US_export.policy:

// Manufacturing policy file.
grant {
    // There is no restriction to any algorithms.
    permission javax.crypto.CryptoAllPermission; 
};

Answer 3

Add below code in your client code :

static {
    Security.insertProviderAt(new BouncyCastleProvider(),1);
 }

with this there is no need to add any entry in java.security file.

Answer 4

I faced the same issue. Tried adding the US_export_policy.jar and local_policy.jar in the java security folder first but the issue persisted. Then added the below in java_opts inside tomcat setenv.shfile and it worked.

-Djdk.tls.ephemeralDHKeySize=2048

Please check this link for further info

Answer 5

The error seems to be thrown when you try and load they keystore from "C:/jakarta-tomcat/webapps/PlanB/Certs/my_pkcs12.p12" here:

ks.load( new FileInputStream(_privateKeyPath), _keyPass.toCharArray() ); 

Have you tried replaceing "/" with "\\" in your file path? If that doesn't help it probably has to do with Java's Unlimited Strength Jurisdiction Policy Files. You could check this by writing a little program that does AES encryption. Try encrypting with a 128 bit key, then if that works, try with a 256 bit key and see if it fails.

Code that does AES encyrption:

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class Test 
{
    final String ALGORITHM = "AES";                       //symmetric algorithm for data encryption
    final String PADDING_MODE = "/CBC/PKCS5Padding";      //Padding for symmetric algorithm
    final String CHAR_ENCODING = "UTF-8";                 //character encoding
    //final String CRYPTO_PROVIDER = "SunMSCAPI";             //provider for the crypto

    int AES_KEY_SIZE = 256;  //symmetric key size (128, 192, 256) if using 256 you must have the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files  installed

    private String doCrypto(String plainText) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException, UnsupportedEncodingException
    {
        byte[] dataToEncrypt = plainText.getBytes(CHAR_ENCODING);

        //get the symmetric key generator
        KeyGenerator keyGen = KeyGenerator.getInstance(ALGORITHM);
        keyGen.init(AES_KEY_SIZE); //set the key size

        //generate the key
        SecretKey skey = keyGen.generateKey();

        //convert to binary
        byte[] rawAesKey = skey.getEncoded();

        //initialize the secret key with the appropriate algorithm
        SecretKeySpec skeySpec = new SecretKeySpec(rawAesKey, ALGORITHM);

        //get an instance of the symmetric cipher
        Cipher aesCipher = Cipher.getInstance(ALGORITHM + PADDING_MODE);

        //set it to encrypt mode, with the generated key
        aesCipher.init(Cipher.ENCRYPT_MODE, skeySpec);

        //get the initialization vector being used (to be returned)
        byte[] aesIV = aesCipher.getIV();

        //encrypt the data
        byte[] encryptedData = aesCipher.doFinal(dataToEncrypt);    

        //initialize the secret key with the appropriate algorithm
        SecretKeySpec skeySpecDec = new SecretKeySpec(rawAesKey, ALGORITHM);

        //get an instance of the symmetric cipher
        Cipher aesCipherDec = Cipher.getInstance(ALGORITHM +PADDING_MODE);

        //set it to decrypt mode with the AES key, and IV
        aesCipherDec.init(Cipher.DECRYPT_MODE, skeySpecDec, new IvParameterSpec(aesIV));

        //decrypt and return the data
        byte[] decryptedData = aesCipherDec.doFinal(encryptedData);

        return new String(decryptedData, CHAR_ENCODING);
    }

    public static void main(String[] args)
    {
        String text = "Lets encrypt me";

        Test test = new Test();

        try {
            System.out.println(test.doCrypto(text));
        } catch (InvalidKeyException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchProviderException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (BadPaddingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Does this code work for you?

You might also want to try specifying your bouncy castle provider in this line:

Cipher.getInstance(ALGORITHM +PADDING_MODE, "YOUR PROVIDER");

And see if it could be an error associated with bouncy castle.