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serafinek
Guest
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 Posted: Mon Oct 17, 2005 10:45 pm Post subject: signing and verifying message |
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Hello
I am trying to sign and verify simple text message. The problem is, that
it even most simple code doesn't work:
KeyPairGenerator gen = KeyPairGenerator.getInstance("RSA");
gen.initialize(512);
KeyPair pair = gen.generateKeyPair();
PrivateKey priv = pair.getPrivate();
PublicKey pub = pair.getPublic();
String hash= "alamakota";
Signature signature = Signature.getInstance("SHA1withRSA");
signature.initSign(priv);
signature.update(hash.getBytes());
byte[] raw = signature.sign();
Signature signature2 = Signature.getInstance("SHA1withRSA");
signature2.initVerify(pub);
if (signature2.verify(raw))
konsola.append("nThe signature is good.");
else
konsola.append("nThe signature is bad.");
and of course i can see "signature is bad".
What am i missing or don't understand?
--
serafinek
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Tommy Grändefors
Guest
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| Posted: Tue Oct 18, 2005 6:40 pm Post subject: Re: signing and verifying message |
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Hi,
You have forgotten to feed your signature2 object with the data that
was signed i.e. you must use 'signature2.update(hash.getBytes())'
before you call 'signature2.verify(raw)':
Signature signature2 = Signature.getInstance("SHA1withRSA");
signature2.initVerify(pub);
signature2.update(hash.getBytes());
if (signature2.verify(raw))
konsola.append("nThe signature is good.");
else
konsola.append("nThe signature is bad.");
Regards,
Tommy Grändefors
www.pheox.com
serafinek wrote:
| Quote: | Hello
I am trying to sign and verify simple text message. The problem is, that
it even most simple code doesn't work:
KeyPairGenerator gen = KeyPairGenerator.getInstance("RSA");
gen.initialize(512);
KeyPair pair = gen.generateKeyPair();
PrivateKey priv = pair.getPrivate();
PublicKey pub = pair.getPublic();
String hash= "alamakota";
Signature signature = Signature.getInstance("SHA1withRSA");
signature.initSign(priv);
signature.update(hash.getBytes());
byte[] raw = signature.sign();
Signature signature2 = Signature.getInstance("SHA1withRSA");
signature2.initVerify(pub);
if (signature2.verify(raw))
konsola.append("nThe signature is good.");
else
konsola.append("nThe signature is bad.");
and of course i can see "signature is bad".
What am i missing or don't understand?
--
serafinek
|
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serafinek
Guest
|
| Posted: Tue Oct 18, 2005 9:03 pm Post subject: Re: signing and verifying message |
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Hi
Thanks, now it's work :)
| Quote: | Hi,
You have forgotten to feed your signature2 object with the data that
was signed i.e. you must use 'signature2.update(hash.getBytes())'
before you call 'signature2.verify(raw)':
Signature signature2 = Signature.getInstance("SHA1withRSA");
signature2.initVerify(pub);
signature2.update(hash.getBytes());
if (signature2.verify(raw))
konsola.append("nThe signature is good.");
else
konsola.append("nThe signature is bad.");
Regards,
Tommy Grändefors
www.pheox.com
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Muhammad Ijaz Khan
Guest
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| Posted: Thu Jan 05, 2006 2:22 pm Post subject: Re: signing and verifying message |
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this problem is exactly opposite than mine :S
and I know I have some problem in my code but its too simple and still I
cant locate it.
can anybody see and tell me the issue? (very) below is my code
Regards,
Ijaz
serafinek wrote:
| Quote: | Hi
Thanks, now it's work :)
Hi,
You have forgotten to feed your signature2 object with the data that
was signed i.e. you must use 'signature2.update(hash.getBytes())'
before you call 'signature2.verify(raw)':
Signature signature2 = Signature.getInstance("SHA1withRSA");
signature2.initVerify(pub);
signature2.update(hash.getBytes());
if (signature2.verify(raw))
konsola.append("nThe signature is good.");
else
konsola.append("nThe signature is bad.");
Regards,
Tommy Grändefors
www.pheox.com
|
=======================================================================================
package com.security.pki;
import java.security.InvalidKeyException;
import java.security.spec.*;
import java.security.PublicKey;
import java.security.SignatureException;
import java.security.NoSuchAlgorithmException;
import java.security.Signature;
import java.io.File;
import java.io.InputStream;
import java.io.IOException;
import java.io.FileInputStream;
/**
* <p>Title: </p>
*
* <p>Description: </p>
*
* <p>Copyright: Copyright (c) 2006</p>
*
* <p>Company: </p>
*
* @author not attributable
* @version 1.0
*/
public class OneMoreTest {
public OneMoreTest() {
}
public static void main(String[] args) {
PublicKey publicKey = null;
try
{
byte[] signbuff = null;
byte[] publicKeyBytes = null;
byte[] msg = null;
try
{
java.security.KeyFactory keyFactory =
java.security.KeyFactory.getInstance("RSA");
File file = new File("public.key");
publicKeyBytes = getBytesFromFile(file);
EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(
publicKeyBytes);
publicKey = keyFactory.generatePublic(publicKeySpec);
file = new File("signature.sig");
signbuff = getBytesFromFile(file);
file = new File("message.msg");
msg = getBytesFromFile(file);
}
catch (IOException e)
{
e.printStackTrace();
}
catch (InvalidKeySpecException ex)
{
ex.printStackTrace();
}
catch (NoSuchAlgorithmException ex)
{
ex.printStackTrace();
}
Signature signature = Signature.getInstance("SHA256WITHRSA");
signature.initVerify(publicKey);
// IF UNCOMMENT BELOW LINE VERIFY METHOD RETURNS FALSE 
//signature.update(msg, 0, msg.length);
boolean val = signature.verify(signbuff);
System.out.println(val);
}
catch (SignatureException e)
{
e.printStackTrace();
}
catch (InvalidKeyException e)
{
e.printStackTrace();
}
catch (NoSuchAlgorithmException e)
{
e.printStackTrace();
}
}
public static byte[] getBytesFromFile(File file) throws IOException {
InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
// You cannot create an array using a long type.
// It needs to be an int type.
// Before converting to an int type, check
// to ensure that file is not larger than Integer.MAX_VALUE.
if (length > Integer.MAX_VALUE) {
// File is too large
}
// Create the byte array to hold the data
byte[] bytes = new byte[(int)length];
// Read in the bytes
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead=is.read(bytes, offset, bytes.length-offset)) >=
0) {
offset += numRead;
}
// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new IOException("Could not completely read file
"+file.getName());
}
// Close the input stream and return bytes
is.close();
return bytes;
}
}
=====================================================================
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