# 2
Ok, now I'm using a base64 encoder and decoder, but I still have a problem: when I put my encoded string between XML tags and then I retrieve it using simple string functions I get into this Exception:
javax.crypto.IllegalBlockSizeException: Data must not be longer than 128 bytes
Here is the code of a test JSP page I've used and the project Beans.
********************************************************************************
JSP page
<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<%@ page
import = "java.io.*"
import = "java.lang.*"
import = "javax.crypto.*"
import = "java.security.*"
%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<jsp:useBean class="ph_prime_pkj.CryptoBean" id="CB"/>
<jsp:useBean class="ph_prime_pkj.KeyHolder" id="KH"/>
<jsp:useBean class="ph_prime_pkj.XMLReader" id="XMLR"/>
<title>KeyGen</title>
</head>
<body>
<h1>Public and Private Keys</h1>
<%
Key privateKey = KH.getPrivateKey("1","120984".toCharArray());
Key publicKey = KH.getPublicKey("1","120984".toCharArray());
out.println("Private and Public keys for farmacia1");
out.println();
out.println("Private: "+privateKey.toString());
out.println();
out.println("Public: "+publicKey.toString());
byte[] enc = CB.encrypt(publicKey,"ciao");
String stringa64 = new sun.misc.BASE64Encoder().encode(enc);
String encoded = "<data>"+stringa64+"</data>";
String encoded2 = XMLR.ReturnAttr(encoded,"data");
byte[] encodedInByte = new sun.misc.BASE64Decoder().decodeBuffer(encoded);
String outString = CB.decrypt(privateKey,encodedInByte);
%>
<%
out.print(outString);
%>
</body>
</html>
******************************************************************************
Crypto Bean
/*
* CryptoBean.java
*
* Created on 19 maggio 2007, 13.58
*/
package ph_prime_pkj;
import java.beans.*;
import java.io.Serializable;
import java.security.Key;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
/**
* @author Luca Bolzoni
*/
public class CryptoBean extends Object implements Serializable {
public CryptoBean() {
}
public static byte[] encrypt(Key key, String text) throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(javax.crypto.Cipher.ENCRYPT_MODE, key);
byte[] encrypted = cipher.doFinal(text.getBytes());
return encrypted;
}
public static String decrypt(Key key, byte[] encrypted) throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(javax.crypto.Cipher.DECRYPT_MODE, key);
byte[] decrypted = cipher.doFinal(encrypted);
return new String(decrypted);
}
}
*****************************************************************************
keyHolder bean
/*
* KeyHolder.java
*
* Created on 18 maggio 2007, 11.46
*/
package ph_prime_pkj;
import java.beans.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Serializable;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.UnrecoverableKeyException;
import java.util.Enumeration;
/**
* @author Luca Bolzoni
*/
public class KeyHolder extends Object implements Serializable {
KeyStore keystore = null;
public KeyHolder() {
}
public PrivateKey getPrivateKey(String alias, char[] password) {
try {
File file = new File(System.getProperty("user.home") + File.separatorChar + ".keystore");
FileInputStream is = new FileInputStream(file);
keystore = KeyStore.getInstance(KeyStore.getDefaultType());
String pass = "mangusta";
keystore.load(is, pass.toCharArray());
is.close();
} catch (java.security.cert.CertificateException e) {
} catch (NoSuchAlgorithmException e) {
} catch (FileNotFoundException e) {
// Keystore does not exist
} catch (KeyStoreException e) {
} catch (IOException e) {
}
try {
// Get private key
Key key = keystore.getKey(alias, password);
if (key instanceof PrivateKey) {
// Get certificate of public key
java.security.cert.Certificate cert = keystore.getCertificate(alias);
// Get public key
PublicKey publicKey = cert.getPublicKey();
// Return a key pair
return (PrivateKey)key;
}
} catch (UnrecoverableKeyException e) {
} catch (NoSuchAlgorithmException e) {
} catch (KeyStoreException e) {
}
return null;
}
public PublicKey getPublicKey(String alias, char[] password) {
try {
File file = new File(System.getProperty("user.home") + File.separatorChar + ".keystore");
FileInputStream is = new FileInputStream(file);
keystore = KeyStore.getInstance(KeyStore.getDefaultType());
String pass = "mangusta";
keystore.load(is, pass.toCharArray());
is.close();
} catch (java.security.cert.CertificateException e) {
} catch (NoSuchAlgorithmException e) {
} catch (FileNotFoundException e) {
// Keystore does not exist
} catch (KeyStoreException e) {
} catch (IOException e) {
}
try {
// Get private key
Key key = keystore.getKey(alias, password);
if (key instanceof PrivateKey) {
// Get certificate of public key
java.security.cert.Certificate cert = keystore.getCertificate(alias);
// Get public key
PublicKey publicKey = cert.getPublicKey();
// Return a key pair
return publicKey;
}
} catch (UnrecoverableKeyException e) {
} catch (NoSuchAlgorithmException e) {
} catch (KeyStoreException e) {
}
return null;
}
}
*********************************************************************************
XMLReader Bean
/*
* XMLReader.java
*
* Created on 1 maggio 2007, 10.06
*/
package ph_prime_pkj;
import java.beans.*;
import java.io.Serializable;
import java.io.File;
import java.io.StringReader;
import org.w3c.dom.Document;
import org.w3c.dom.*;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
/**
* @author Valerio
*/
public class XMLReader extends Object implements Serializable {
public String ReturnAttr(String xml, String attr){
String temp="";
int begin = xml.indexOf("<"+attr+">") + attr.length() + 2;
int end = xml.indexOf("</"+attr+">");
temp = (String) xml.subSequence(begin, end);
return temp;
}
}
Thanks a lot.
