What Is Digital Signature?

This section describes the digital signature technology, the data signing process and the signature verification process.

What is Digital Signature? Digital signature is a computer technology to protect digital data in two security areas: authentication and integrity.

The following diagram illustrates a common way to applying the digital signature technology to protect your data when sending it to someone else:

Sender                               Receiver

Public key      --> |          | --> Public key --
                    |          |                 |
Private key         |          |                 |
           |        |          |                 |
Data       |    --> |          | --> Data ------ |
   |       |        |          |               | |
   v       v        |          |               | |
   Signing process  | Delivery |               | |
      |             |          |               | |
      v             |          |               | |
      Signature --> |          | --> Signature | |
                    |          |        |      | |
                    |          |        v      v v
                    |          |        Verification process
                    |          |           |
                    |          |           v
                    |          |           OK?

As you can see in the above diagram, in order to apply the digital signature technology, the sender needs to:

The receiver needs to:

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

 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

 Character Set Encoding Maps

 Encoding Conversion Programs for Encoded Text Files

 Socket Network Communication

 Datagram Network Communication

 DOM (Document Object Model) - API for XML Files

 SAX (Simple API for XML)

 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

 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


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