Hi everybody!
I am working on troubleshooting an encryption/decryption program which is currently in production.
The JDK version is 1.3.1.
The encryption program takes a payload string which is a combination of several parameters (each parameter is URL encoded) and generates an encrypted URL following the steps below:
//
// Steps for creating an encrypted URL:
//
// 1 - Calculate the checksum
// 2 - Concatenate the checksum and payload
// 3 - URL Encode
// 4 - Compress the string using zipIt (GZIP)
// 5 - Encrypt using Blowfish and SunJCE
// 6 - Base 64 encode
// 7 - URL encode
// 8 - Return the complete string

The program works as long as the caller calls it once.
But, if the program is called in a loop, sometimes the output is invalid (5% of the time). And this is totally random and is not driven by any of the parameter values being passed in.
I am pasting relevant sections of the code. Could anybody help me with this to see what could be causing it?


Thanks in advance!


ss

			

			

			public class PDFWebApiDelegate {
			

			

			

			public PDFWebApiDelegate() {
			

			}
			

			

			public static String encryptPayload (String payload, String authKey)
			{
			

			

			try {
			

			

			BlowFishUtil bfUtil = new BlowFishUtil();
			

			

			String sCheckSum    = getMD5Checksum(payload);
			

			String encodeBuffer = sCheckSum + payload;
			

			encodeBuffer        = URLEncoder.encode(encodeBuffer);
			

			byte[] aryEncodeBuf = zipIt(encodeBuffer);
			

			aryEncodeBuf        = bfUtil.encryptSecretKey(authKey.getBytes(),aryEncodeBuf);
			

			encodeBuffer        = Base64.encodeBytes(aryEncodeBuf);
			

			encodeBuffer        = URLEncoder.encode(encodeBuffer);
			

			return encodeBuffer;
			

			}
			

			catch (Exception e) {
			

			return null;
			

			}
			

			}
			

			

			public static String decryptPayload (String payload, String authKey)
			{
			

			

			try {
			

			String decodeBuffer = "";
			

			BlowFishUtil bfUtil = new BlowFishUtil();
			

			decodeBuffer = URLDecoder.decode(payload);
			

			decodeBuffer = Base64.decodeToString(decodeBuffer);
			

			byte[] aryDecodeBuf = bfUtil.decryptSecretKey(authKey.getBytes(), decodeBuffer.getBytes());
			

			aryDecodeBuf = unzipIt(aryDecodeBuf);
			

			String sBuf = new String(aryDecodeBuf);
			

			sBuf = URLDecoder.decode(sBuf);
			

			int iPos = sBuf.indexOf("gh=");
			

			if (iPos>=0) {
			

			

			String sURLCheckSum = sBuf.substring(0,iPos);
			

			sBuf                = sBuf.substring(iPos,sBuf.length());
			

			String sCheckSum    = getMD5Checksum(sBuf);
			

			

			if (!sCheckSum.equals(sURLCheckSum)) {
			

			

			}
			

			

			

			}
			

			

			return new String(sBuf);
			

			}
			

			catch (Exception e) {
			

			return null;
			

			}
			

			}
			

			

			

			private static String getMD5Checksum( String mess )
			{
			

			

			String hexHashCode = "";
			

			String hashCode = "";
			

			

			try {
			

			

			MessageDigest md = MessageDigest.getInstance("MD5");
			

			

			byte[] message = mess.getBytes("UTF-8");
			

			

			md.update( message );
			

			

			byte[] hash = md.digest();
			

			

			for ( int i=0; i
			< hash.length; i++ ){
			

			

			int x = hash[i] & 0xFF;
			

			if (x
			< 0x10) {
			

			hexHashCode += "0";
			

			}
			

			hexHashCode += (Integer.toHexString(x));
			

			

			hashCode += hash[i]+" _ ";
			

			}
			

			

			}
			

			catch (Exception e) {
			

			e.printStackTrace();
			

			return "error";
			

			}
			

			

			return hexHashCode;
			

			}
			

			

			private static byte[] zipIt ( String parameterString )
			

			{
			

			

			byte[] zipped;
			

			

			try {
			

			

			ByteArrayOutputStream catcher = new ByteArrayOutputStream();
			

			GZIPOutputStream gzipOut = new GZIPOutputStream( catcher );
			

			

			byte[] bytesToZip = parameterString.getBytes();
			

			

			gzipOut.write( bytesToZip, 0, bytesToZip.length );
			

			gzipOut.close();
			

			

			return catcher.toByteArray();
			

			

			}
			

			catch ( Exception ioe ) {
			

			ioe.printStackTrace();
			

			return "error".getBytes();
			

			}
			

			}
			

			

			private static byte[] unzipIt ( byte[] buffer ) {
			

			

			ByteArrayOutputStream outBuffer = new ByteArrayOutputStream();
			

			ByteArrayInputStream  inBuffer  = new ByteArrayInputStream(buffer);
			

			

			try {
			

			GZIPInputStream gzip = new GZIPInputStream(inBuffer);
			

			byte[] tmpBuffer = new byte[256];
			

			int n;
			

			while ((n = gzip.read(tmpBuffer)) >= 0) {
			

			outBuffer.write(tmpBuffer, 0, n);
			

			}
			

			return outBuffer.toByteArray();
			

			}
			

			catch (Exception e) {
			

			return null;
			

			}
			

			}
			

			}
			

			

			

		

			

			// encryptSecretKey - uses javax.crypto.SecretKey to encrypt a java.util.String.  It returns
			

			//                    this string as a byte array.
			

			//
			

			public static byte[] encryptSecretKey(byte[] keyBytes, byte[] unencrypted)
			

			{
			

			

			try {
			

			

			

			

			Provider sunJce = new com.sun.crypto.provider.SunJCE();
			

			Security.addProvider(sunJce);
			

			

			SecretKeySpec skeySpec = new SecretKeySpec(keyBytes, "Blowfish");
			

			Cipher cipher = Cipher.getInstance("Blowfish");
			

			cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
			

			

			byte[] myEncrypt = cipher.doFinal(unencrypted);
			

			

			

			return myEncrypt;
			

			}
			

			catch (Exception e) {
			

			

			e.printStackTrace();
			

			return null;
			

			}
			

			}
			

			

			//
			

			// decryptSecretKey - uses a java.crypto.SecretKey to decrypt a byte array of encrypted characters
			

			//
			

			public static byte[] decryptSecretKey(byte[] keyBytes, byte[] encrypted)
			

			{
			

			

			try {
			

			Provider sunJCE = new com.sun.crypto.provider.SunJCE();
			

			Security.addProvider(sunJCE);
			

			

			SecretKeySpec skeySpec = new SecretKeySpec(keyBytes, "Blowfish");
			

			

			Cipher cipher = javax.crypto.Cipher.getInstance("Blowfish");
			

			

			cipher.init(javax.crypto.Cipher.DECRYPT_MODE, skeySpec);
			

			

			byte[] decrypted = cipher.doFinal(encrypted);
			

			

			return decrypted;
			

			}
			

			catch (Exception e) {
			

			return null;
			

			}
			

			}