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I'm using RSA encryption for converting simpletext to encrypted form.

my plain text is : hello

encrypted text : [B@d7eed7

Now, how to convert encrypted text into simple plain text i'm using following code

KeyPairGenerator keygenerator = KeyPairGenerator.getInstance("RSA");
SecureRandom random = SecureRandom.getInstance("SHA1PRNG", "SUN");
keygenerator.initialize(1024, random);

KeyPair keypair = keygenerator.generateKeyPair();
PrivateKey privateKey = keypair.getPrivate();
PublicKey publicKey = keypair.getPublic();
Cipher cipher = Cipher.getInstance("RSA");

String arrayStr = "[b@d7eed7";
byte ciphertext = arrayStr.getBytes();
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] cleartext1 = cipher.doFinal(ciphertext);
System.out.println("the decrypted cleartext is: " + new String(cleartext1));

i'm getting javax.crypto.BadPaddingException: Data must start with zero

need help !!

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  • possible duplicate stackoverflow.com/questions/6483181/… Commented May 3, 2012 at 12:47
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    I'm pretty sure your encrypted text is not [B@d7eed7 (or at least not in the way you think). Commented May 3, 2012 at 12:52
  • it is not for encryption, encryption part have been already done. Now, i've the encrypted text [b@77eed7, which is in string format, now i want to return it back to the original text. Commented May 3, 2012 at 12:54
  • There is a lot of wrongness potential in this question, even before the wrong assumption that byte [].toString() is meaningful. You should not even be trying to take the byte [] result of encryption and converting it to character string unless you need to transfer it through a character-only channel. In that case, you should using something like base64 encoding. Commented May 4, 2012 at 0:57

3 Answers 3

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The problem is that [B@d7eed7 is not the encrypted text. It simply shows the type and the address of the byte array, not its contents.

For more information, see https://stackoverflow.com/a/5500020/367273

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6 Comments

i've already visited that link, but it hard for me to understand. I' mean i didn't get what he/she is saying for the solution
@coders_zone: He is saying "Use new String(array, encoding) and not array.toString()".
then, how can i decrypt the same array to the plain text.
i was trying new String(encryptarr,"Base64"), then it showing exception UnsupportedEncodeingException: Base64
Base64 is not a character encoding. Do it like this: encode your array into base64 and use ASCII character encoding for the output string.
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I just looked to the "Related" part on the right side of the screen and... Convert Java string to byte array

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to convert string to byte array you can use the following:

String source = "0123456789";
byte[] byteArray = source.getBytes("specify encoding alongside endianess");// e.g "UTF-16LE", "UTF-16"..

For more info you can check here, here and here.

Good luck!

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