java.security.Signature - The Data Signing Class

This section describes the data signing class, java.security.Signature, and its major methods like update() and sign().

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.

Last update: 2014.

Table of Contents

 About This JDK Tutorial Book

 Downloading and Installing JDK 1.8.0 on Windows

 Downloading and Installing JDK 1.7.0 on Windows

 Downloading and Installing JDK 1.6.2 on Windows

 Java Date-Time API

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 Locales, Localization Methods and Resource Bundles

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 DTD (Document Type Definition) - XML Validation

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 XSL (Extensible Stylesheet Language)

 Message Digest Algorithm Implementations in JDK

 Private key and Public Key Pair Generation

 PKCS#8/X.509 Private/Public Encoding Standards

Digital Signature Algorithm and Sample Program

 What Is Digital Signature?

 The Signing Process and the Verification Process

java.security.Signature - The Data Signing Class

 JcaSignatureTest.java - Signature Test Program

 Signature Test Program Result

 JcaSign.java - Signature Generation Sample Program

 JcaVerify.java - Signature Verification Sample Program

 "keytool" Commands and "keystore" Files

 KeyStore and Certificate Classes

 Secret Key Generation and Management

 Cipher - Secret Key Encryption and Decryption

 The SSL (Secure Socket Layer) Protocol

 SSL Socket Communication Testing Programs

 SSL Client Authentication

 HTTPS (Hypertext Transfer Protocol Secure)

 Outdated Tutorials

 References

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