**Cryptography Tutorials - Herong's Tutorial Examples** - Version 5.40, by Dr. Herong Yang

What is ECB (Electronic CodeBook) Operation Mode?

This section describes what is ECB (Electronic CodeBook) Operation Mode - each plaintext block is encrypted independently without any input from other blocks.

ECB (Electronic CodeBook) is the simplest operation mode comparing to other operation modes. It can be described by the formula and the diagram below with notations defined earlier:

C[i] = Ek(P[i]) P[1]--| P[2]--| P[3]--| | | | Ek() Ek() Ek() | | | C[1] C[2] C[3]

As you can see from the formula and the diagram, in ECB mode, each ciphertext block is obtained by applying the DES encryption process to the current plaintext block directly. So the current ciphertext block has not dependency on any previous plaintext blocks.

The disadvantage of ECB mode is that identical plaintext blocks are encrypted to identical ciphertext blocks; thus, it does not hide data patterns well. In some senses it doesn't provide message confidentiality at all, and it is not recommended for cryptographic protocols.

wikipedia has a striking example of the degree to which ECB can reveal patterns in the plaintext. The example uses a bitmap file of an image as the plaintext message. After applying DES encryption in ECB mode, the ciphertext message can be viewed as a new bitmap image file. The new image does reveal major patterns of the original image very clearly.

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

DES Encryption Operation Mode Introduction

►What is ECB (Electronic CodeBook) Operation Mode?

What is CBC (Cipher Block Chaining) Operation Mode?

What is CFB (Cipher FeedBack) Operation Mode?

What is OFB (Output FeedBack) Operation Mode?

JCE DES Operation Mode Testing Program

JCE DES Operation Mode Testing Program Result

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

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"