Error in Decryption

Question

Dear All,
This is my first post. Require your help in the resolving the following issue.
I have an encrypter and corresponding decrypter using DES algorithm compiled using Sun JDK. Now the encrypter is being used in IBM JRE environment. The file is getting encrypted, but when I try to decrypt it using Sun JDK, it is looking for the ibm classes (com.ibm.provider.DESKey) and is not able to decrypt the file. Can anyone help, why is the decrypter looking for the ibm classes.
The JRE versions of both IBM and Sun are 1.4.2.
Thanks in advance for the help...

Answer 1

The decrypter class
// Decompiled by Jad v1.5.8f. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://www.kpdus.com/jad.html
// Decompiler options: packimports(3)
// Source File Name:   Decrypter.java
package icici.matrix.utils;
import java.io.FileInputStream;
import java.io.PrintStream;
import java.math.BigInteger;
import java.util.Properties;
public class Decrypter
    static class Params
        BigInteger p;
        BigInteger q;
        BigInteger n;
        BigInteger d;
        BigInteger e;
        BigInteger phi;
        BigInteger max;
        Params()
            p = new BigInteger("0");
            q = new BigInteger("0");
            n = new BigInteger("0");
            d = new BigInteger("0");
            e = new BigInteger("15");
            phi = new BigInteger("0");
    public Decrypter()
    public String decrypt()
        Params par = new Params();
        String password = "";
        String propFile = "app.properties";
        try
            Properties prop = new Properties();
            FileInputStream finput = new FileInputStream(propFile);
            prop.load(finput);
            password = (String)prop.get("password");
            System.out.println(password);
        catch(Exception e)
            e.printStackTrace();
        String cipherText = password;
        String cipherTextTemp = "";
        String decipheredText = "";
        String outputText = "";
        boolean flag = cipherText.startsWith("P");
        if(flag)
            cipherText = cipherText.substring(1, cipherText.length());
        int blockSize = 4;
        if(blockSize % 2 != 0)
            System.out.println("blockSize must be even");
            System.exit(1);
        String maxEncodedString = "";
        for(int cnt = 0; cnt < blockSize; cnt += 2)
            maxEncodedString = maxEncodedString + "94";
        par.max = new BigInteger(maxEncodedString);
        par.p = par.max.divide(new BigInteger("502"));
        Decrypter obj = new Decrypter();
        obj.getKeys(par, blockSize);
        decipheredText = obj.doRSA(cipherText, par.d, par.n, blockSize);
        System.out.println("decipheredText\n" + decipheredText);
        outputText = obj.decode(decipheredText);
        if(flag)
            outputText = outputText.substring(0, outputText.length() - 1);
        System.out.println("outputText\n" + outputText);
        return outputText;
    void getKeys(Params par, int blockSize)
        BigInteger bigOne = new BigInteger("1");
        for(; !par.p.isProbablePrime(1000); par.p = par.p.add(bigOne));
        String firstQ = par.p.subtract(bigOne);
        par.q = new BigInteger(firstQ);
        for(par.n = par.p.multiply(par.q); par.n.toString().length() > blockSize; par.n = par.p.multiply(par.q))
            par.q = par.q.divide(new BigInteger("2"));
        for(par.q = par.q.divide(new BigInteger("2")); !par.q.isProbablePrime(1000); par.q = par.q.subtract(bigOne));
        for(par.n = par.p.multiply(par.q); par.n.compareTo(par.max) <= 0; par.n = par.p.multiply(par.q))
            for(par.q = par.q.add(bigOne); !par.q.isProbablePrime(1000); par.q = par.q.add(bigOne));
        if(par.n.toString().length() > blockSize || par.n.compareTo(par.max) <= 0)
            System.out.println("Required conditions are not met");
            System.exit(1);
        BigInteger pPrime = par.p.subtract(bigOne);
        BigInteger qPrime = par.q.subtract(bigOne);
        for(par.phi = pPrime.multiply(qPrime); !par.e.gcd(par.phi).equals(bigOne); par.e = par.e.add(bigOne));
        par.d = par.e.modInverse(par.phi);
        if(blockSize > 6)
            System.exit(0);
    String decode(String encodedText)
        String temp = "";
        String decodedText = "";
        for(int cnt = 0; cnt < encodedText.length(); cnt += 2)
            temp = encodedText.substring(cnt, cnt + 2);
            int val = Integer.parseInt(temp) + 32;
            decodedText = decodedText + String.valueOf((char)val);
        return decodedText;
    String doRSA(String inputString, BigInteger exp, BigInteger n, int blockSize)
        String temp = "";
        String outputString = "";
        for(int cnt = 0; cnt < inputString.length(); cnt += blockSize)
            temp = inputString.substring(cnt, cnt + blockSize);
            BigInteger block = new BigInteger(temp);
            BigInteger output = block.modPow(exp, n);
            for(temp = output.toString(); temp.length() < blockSize; temp = "0" + temp);
            outputString = outputString + temp;
        return outputString;
    public String decrypt(String password)
        Params par = new Params();
        String cipherText = password;
        String cipherTextTemp = "";
        String decipheredText = "";
        String outputText = "";
        boolean flag = cipherText.startsWith("P");
        if(flag)
            cipherText = cipherText.substring(1, cipherText.length());
        int blockSize = 4;
        if(blockSize % 2 != 0)
            System.out.println("blockSize must be even");
            System.exit(1);
        String maxEncodedString = "";
        for(int cnt = 0; cnt < blockSize; cnt += 2)
            maxEncodedString = maxEncodedString + "94";
        par.max = new BigInteger(maxEncodedString);
        par.p = par.max.divide(new BigInteger("502"));
        Decrypter obj = new Decrypter();
        obj.getKeys(par, blockSize);
        decipheredText = obj.doRSA(cipherText, par.d, par.n, blockSize);
        System.out.println("decipheredText\n" + decipheredText);
        outputText = obj.decode(decipheredText);
        if(flag)
            outputText = outputText.substring(0, outputText.length() - 1);
        System.out.println("outputText\n" + outputText);
        return outputText;
}