Cryptography Tutorials - Herong's Tutorial Examples - v5.42, by Herong Yang
java.security.Signature - The Data Signing Class
This section describes the data signing and verification Java class, java.security.Signature, and its major methods like update(), sign() and verify().
The java.security.Signature class is an abstract class providing a link to implementation classes of digital signature algorithms provided by various security package providers. Major methods in the KeyPairGenerator class:
getInstance() - Returns a Signature object of the specified algorithm from the implementation of the specified provider. If provider is not specified, the default implementation is used. This is a static method.
initSign() - Initializes the current Signature object with the specified private key to be ready to take input data for generating a new signature.
initVerify() - Initializes the current Signature object with the specified public key to be ready to take input data for verifying an existing signature.
update() - Adds more data to the current Signature object for signature generation or signature verification.
sign() - Generates a new signature for the input data received so far in the current Signature object, and returns the signature as a byte array. It also removes the input data.
verify() - Verifies the input data received so far in the current Signature object against the specified signature, and returns true or false. It also removes the input data.
getAlgorithm() - Returns the algorithm name of the current Signature object.
getProvider() - Returns the provider as a Provider object of the current Signature object.
See the next section on how to write a sample program.
Table of Contents
Introduction to AES (Advanced Encryption Standard)
DES Algorithm - Illustrated with Java Programs
DES Algorithm Java Implementation
DES Algorithm - Java Implementation in JDK JCE
DES Encryption Operation Modes
PHP Implementation of DES - mcrypt
Blowfish - 8-Byte Block Cipher
Secret Key Generation and Management
Cipher - Secret Key Encryption and Decryption
RSA Implementation using java.math.BigInteger Class
Introduction of DSA (Digital Signature Algorithm)
►Java Default Implementation of DSA
DsaKeyGenerator.java - Generating DSA Key Pair
DSA 512-bit and 1024-bit Key Pair Examples
DsaKeyChecker.java - Reading and Checking DSA Keys
Example of DSA Key Parameters and Properties
►java.security.Signature - The Data Signing Class
DsaSignatureGenerator.java - Generating DSA Digital Signature
DsaSignatureGenerator.java Test Results
DsaSignatureVerifier.java - Verifying DSA Digital Signature
DsaSignatureVerifier.java Test Results
Private key and Public Key Pair Generation
PKCS#8/X.509 Private/Public Encoding Standards
Cipher - Public Key Encryption and Decryption
OpenSSL Introduction and Installation
OpenSSL Generating and Managing RSA Keys
OpenSSL Generating and Signing CSR
OpenSSL Validating Certificate Path
"keytool" and "keystore" from JDK
"OpenSSL" Signing CSR Generated by "keytool"
Migrating Keys from "keystore" to "OpenSSL" Key Files
Certificate X.509 Standard and DER/PEM Formats
Migrating Keys from "OpenSSL" Key Files to "keystore"