Generating and Verifying Signatures |
Now that you have generated a signature for some data, you need to save the signature bytes in one file, and the public key bytes in another so you can send (via modem, floppy, mail, etc.) someone elseThe receiver can verify that the data actually came from you and was not modified in transit by running the
- the data for which the signature was generated,
- the signature, and
- the public key
VerSig
program you will generate in the upcoming Verifying a Digital Signature steps. That program uses the public key to verify that the signature received is the true signature for the data received.Recall the signature was placed in a byte array named
realSig
. You can save the signature bytes in a file namedsig
via the following:For the public key, recall the public key was placed in a PublicKey object named/* save the signature in a file */ FileOutputStream sigfos = new FileOutputStream("sig"); sigfos.write(realSig); sigfos.close();pub
in Generate Public and Private Keys. You can get the encoded key bytes by calling thegetEncoded
method, and then store the encoded bytes in a file. You can name the file whatever you want. If, for example, your name is Susan, you might name it something likesuepk
(for "Sue's public key"), as in the following:/* save the public key in a file */ byte[] key = pub.getEncoded(); FileOutputStream keyfos = new FileOutputStream("suepk"); keyfos.write(key); keyfos.close();
Generating and Verifying Signatures |