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You have now created the completetestSig.java
program. Use the Java compiler to compile it.Here's the full
source code
, with some comments added:
import java.io.*; import java.security.*; class testSig { public static void main(String[] args) { /* Test generating and verifying a DSA signature */ try { /* generate a key pair */ KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA"); keyGen.initialize(1024, new SecureRandom()); KeyPair pair = keyGen.generateKeyPair(); /* create a Signature object to use * for signing and verifying */ Signature dsa = Signature.getInstance("SHA/DSA"); /* initialize the Signature object for signing */ PrivateKey priv = pair.getPrivate(); dsa.initSign(priv); /* Update and sign the data */ FileInputStream fis = new FileInputStream(args[0]); byte b; while (fis.available() != 0) { b = (byte) fis.read(); dsa.update(b); }; fis.close(); /* Now that all the data to be signed * has been read in, sign it */ byte[] sig = dsa.sign(); /* Verify the signature */ /* Initialize the Signature object for verification */ PublicKey pub = pair.getPublic(); dsa.initVerify(pub); /* Update and verify the data */ fis = new FileInputStream(args[0]); while (fis.available() != 0) { b = (byte) fis.read(); dsa.update(b); }; fis.close(); boolean verifies = dsa.verify(sig); System.out.println("signature verifies: " + verifies); } catch (Exception e) { System.err.println("Caught exception " + e.toString()); } } }
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