Streaming out de-encrypted data

Question

Hi,
I have 2 classes "parsing.java" and "enc.java". "parsing.java" parses an xml file "INFO.xml", to get a few attribute values. I'm using SAX parsing.
However, "INFO.xml" is encrypted (password based encryption), and needs to be de-encrypted before it can be parsed. So "parsing.java" calls "enc.java" which de-encrypts the xml file, and creates the "readable xml file" say "rINFO.xml". Then the program reads the xml file.
parsing.java
String passphrase = "123456789";
String oFile = "C:\\rINFO.xml";
String iFile = "C:\\INFO.xml";
enc f = new enc();f.decFile(iFile,oFile,passphrase);  //starts parsing reader.parse(oFile);....enc.java
public class enc
     public void decFile(String inputFile, String outputFile, String  passphrase)   
     InputStream in = new FileInputStream(inputFile);       
OutputStream out = new FileOutputStream(outputFile);      
byte[] inBytes = new byte[blockSize];       
byte[] outBytes = new byte[outputSize];     
while(more)      
{            inLength = in.read(inBytes);                      
if(inLength == blockSize)           
int outLength = cipher.update(inBytes, 0, blockSize,  outBytes);                out.write(outBytes, 0, outLength);           
else              
more = false;       
............. You should have noticed that I'm creating a new file "rINFO.xml" and sending the de-encrypted data to that file. However, I would like to stream out the de-encrypted contents using output stream to "parsing.java", and do not want to save it as a file, because the whole purpose of encryption is lost otherwise.
1)Is there a way of having the de-encrytped xml file in memory and then parsing that ?
2) or streaming the de-encrypted contents to "parsing.java", where I can use
reader.parse(new InputSource(new InputStreamReader (inStream)));
instead of
reader.parse(oFile);
any help appreciated .
-Sara

Answer 1

Have you looked at the Cipher stream classes?
http://java.sun.com/j2se/1.4.2/docs/api/javax/crypto/CipherInputStream.html
http://java.sun.com/j2se/1.4.2/docs/api/javax/crypto/CipherOutputStream.html