JDK Tutorials - Herong's Tutorial Examples - v6.32, by Herong Yang
Key Pair Sample Program - JcaKeyPair.java
This section provides a tutorial example on how to write simple program to generate a pair of private key and public key for the RSA or DSA algorithm.
The following sample program shows you how to invoke the key pair generation algorithms implemented by the default provider, Sun, and generate key pairs.
/* JcaKeyPair.java * Copyright (c) HerongYang.com. All Rights Reserved. */ import java.io.*; import java.math.*; import java.security.*; import java.security.interfaces.*; class JcaKeyPair { public static void main(String[] a) { if (a.length<3) { System.out.println("Usage:"); System.out.println("java JcaKeyPair keySize output" +" algorithm"); return; } int keySize = Integer.parseInt(a[0]); String output = a[1]; String algorithm = a[2]; // RSA, DSA try { getKeys(keySize,output,algorithm); } catch (Exception e) { System.out.println("Exception: "+e); return; } } private static void getKeys(int keySize, String output, String algorithm) throws Exception { KeyPairGenerator kg = KeyPairGenerator.getInstance(algorithm); kg.initialize(keySize); System.out.println(); System.out.println("KeyPairGenerator Object Info: "); System.out.println("Algorithm = "+kg.getAlgorithm()); System.out.println("Provider = "+kg.getProvider()); System.out.println("Key Size = "+keySize); System.out.println("toString = "+kg.toString()); KeyPair pair = kg.generateKeyPair(); PrivateKey priKey = pair.getPrivate(); PublicKey pubKey = pair.getPublic(); String fl = output+".pri"; FileOutputStream out = new FileOutputStream(fl); byte[] ky = priKey.getEncoded(); out.write(ky); out.close(); System.out.println(); System.out.println("Private Key Info: "); System.out.println("Algorithm = "+priKey.getAlgorithm()); System.out.println("Saved File = "+fl); System.out.println("Size = "+ky.length); System.out.println("Format = "+priKey.getFormat()); System.out.println("toString = "+priKey.toString()); fl = output+".pub"; out = new FileOutputStream(fl); ky = pubKey.getEncoded(); out.write(ky); out.close(); System.out.println(); System.out.println("Public Key Info: "); System.out.println("Algorithm = "+pubKey.getAlgorithm()); System.out.println("Saved File = "+fl); System.out.println("Size = "+ky.length); System.out.println("Format = "+pubKey.getFormat()); System.out.println("toString = "+pubKey.toString()); } }
Note that:
See next sections on test result of this sample program.
Table of Contents
Date, Time and Calendar Classes
Date and Time Object and String Conversion
Number Object and Numeric String Conversion
Locales, Localization Methods and Resource Bundles
Calling and Importing Classes Defined in Unnamed Packages
HashSet, Vector, HashMap and Collection Classes
Character Set Encoding Classes and Methods
Encoding Conversion Programs for Encoded Text Files
Datagram Network Communication
DOM (Document Object Model) - API for XML Files
DTD (Document Type Definition) - XML Validation
XSD (XML Schema Definition) - XML Validation
XSL (Extensible Stylesheet Language)
Message Digest Algorithm Implementations in JDK
►Private key and Public Key Pair Generation
Private and Public Keys and Related Interfaces
KeyPair and KeyPairGenerator Classes
►Key Pair Sample Program - JcaKeyPair.java
DSA Private Key and Public Key Pair Sample
RSA Private Key and Public Key Pair Sample
DiffieHellman Private Key and Public Key Pair Sample
PKCS#8/X.509 Private/Public Encoding Standards
Digital Signature Algorithm and Sample Program
"keytool" Commands and "keystore" Files
KeyStore and Certificate Classes
Secret Key Generation and Management
Cipher - Encryption and Decryption
The SSL (Secure Socket Layer) Protocol
SSL Socket Communication Testing Programs