1. INTRODUCTION
2. DATA ENCRYPTION
2.1 What Is Data Encryption?
2.2 How Is Data Encryption Achieved?
2.3 Where Should Data Encryption Be Used?
2.4 When Should Data Encryption Be Used?
2.5 Why Is a Data Encryption Standard Necessary?
2.6 What Are the Requirements of a DES?
2.7 What Role Has NBS Played in the DES?
3. DATA ENCRYPTION METHODS
3.1 Basic Methods
3.2 Encoding and Enciphering
3.3 Block Ciphers
3.4 Product Ciphers
3.5 Recirculating Block Product Cipher
3.6 Characteristics of the DES Algorithm
4. SECURITY THREATS REDUCED THROUGH ENCRYPTION
4.1 Transmission Threats
4.2 Storage Threats
5. IMPLEMENTATION OF THE ALGORITHM
5.1 Basic Implementation
5.1.1 Electronic Devices
5.1.2 Basic Implementation Control Functions
5.2 Secondary Implementation
5.2.1 Secondary Implementation Control Functions
5.2.2 Error Handling
5.3 Modes of Operation
5.3.1 The Electronic Codebook (ECB) Mode
5.3.2 The Cipher Block Chaining (CBC) Mode
5.3.3 The Cipher Feedback (CFB) Mode
5.3.4 The Output Feedback (OFB) Mode
5.3.5 Relationship of CBC and 64-bit CFB
5.4 CBC and CFB for Data Authentication
5.5 System Implementation
6. KEY MANAGEMENT
6.1 Key Generation and Protection
6.2 Key Distribution
6.2.1 Communication Security
6.2.2 File Security
6.3 Key Destruction
7. TRANSPARENCY IN COMMUNICATIONS PROTOCOLS
7.1 Transparent Use of Encryption
7.2 Nontransparent Use of Encryption
7.3 Communication Standards Based on the DES
8. USING DES TO MAP A CHARACTER SET ONTO ITSELF
8.1 Example I (Digital)
8.1.1 Solution
8.1.2 Decryption
8.2 Example II (Alphanumerics)
8.3 Example III (General Solution)
8.4 Solution for Plaintext Bias
9 REFERENCES