Converting String to Byte[] array

[Farakh khan]

Hello,

 String vpc_SecureHash="5DB0F8628C4801B24110FD52056345FG";

	String s  = vpc_SecureHash;
	Byte[] convertme = s.getBytes("UTF8"); 

The above code is throwing error of:
Incompatible type
found: byte[]
required: java.lang.byte[]

Thanks in anticipation

[Wouter Oet]

You will need to create a Byte[] and set all the elements using a loop.

[Farakh khan]

Wouter Oet wrote:You will need to create a Byte[] and set all the elements using a loop.

String s  = vpc_SecureHash;
	Byte[] convertme ;

	for(int i=0; i<s.length(); i++){
	convertme[i]= s.getBytes();
	}

Same incompatible error

thanks again for helping

[Wouter Oet]

getBytes returns an array of bytes (primitive). To convert it into a Byte[] (wrapper) you'll need to create a new Byte[] and set the values of that.
Like this:

String s  = vpc_SecureHash;
byte[] convertme = s.getBytes();;
Byte[] result = new Byte[convertme.length];
for(int i=0; i<convertme.length; i++){
   result = convertme[i];
}

[Farakh khan]

Wouter Oet wrote:getBytes returns an array of bytes (primitive). To convert it into a Byte[] (wrapper) you'll need to create a new Byte[] and set the values of that.
Like this:

String s  = vpc_SecureHash;
byte[] convertme = s.getBytes();;
Byte[] result = new Byte[convertme.length];
for(int i=0; i<convertme.length; i++){
   result = convertme[i];
}

Hello,

Thanks for your reply.

public static String md5sum(byte[] convertme)throws NoSuchAlgorithmException{

	
	MessageDigest md = MessageDigest.getInstance("MD5");
	return new String(md.digest(convertme));
}


	
	String vpc_SecureHash="5DB0F8628C4801B24110FD52056WEJY5";

	String s  = vpc_SecureHash;  
	
          MessageDigest m=MessageDigest.getInstance("MD5");
          m.update(s.getBytes(),0,s.length());

	  String securedHash = new BigInteger(1,m.digest()).toString(16);

   		byte[] convertme = s.getBytes();;  
   		byte[] result = new byte[convertme.length];  

   	for(int i=0; i<convertme.length; i++){  
   	result[i] = convertme[i];  
   	}  

	
	  out.println("vpc_SecureHash=5DB0F8628C4801B24110FD52056WEJY5<br>"+
	  "Converted to="+securedHash+"<br>Converted to Original Hash="+m.digest(result));

OUTPUT:
vpc_SecureHash=5DB0F8628C4801B24110FD52056WEJY5
Converted to=1f8a39f895956b6ebf5ae9268f27cd27
Converted to Original Hash=[B@136a1a1

Please check it again as to how can I convert back the hash (md5)

Best regards

[James Sabre]

On the whole it is very difficult to see what your code is trying to do so it is not obvious to me what you are asking.

Are you asking how to take a message digest and recover the message? If so you can't because a message digest is a one way algorithm. There are sites that say they can do this but all they do is maintain a large database of mappings from messages to digests. There are an infinite number of possible messages but only a finite number of digest values (2^16 for MD5) so for each digest value there are an infinite number of messages that can be used to create it.

Are you asking why
Converted to Original Hash=[B@136a1a1
is not what you expect? If so you should note that the toString() method of an array (your println() uses it behind the scenes) does not in any way reflect the content of that array. You will need to hex encode the content if you expect to see hex.

Please note - the line

String securedHash = new BigInteger(1,m.digest()).toString(16);  

does not preserve leading zeros so is a very bad way of converting a digest to a hex string. You would do better to use one of the open source libraries such as that from the Jakarta Codec project.

[Wouter Oet]

Farakh khan wrote:Please check it again as to how can I convert back the hash (md5)

You can't convert it back. It's a hash. That's basically one way encryption.

[Farakh khan]

Wouter Oet wrote:

Farakh khan wrote:Please check it again as to how can I convert back the hash (md5)

You can't convert it back. It's a hash. That's basically one way encryption.

Thanks for replies

If this is one way encryption then what is mean by comparing has?

Best regards

[Ulf Dittmer]

Let's continue the discussion in this duplicate thread, which is largely identical.