Prevention of unauthorized access to settlement and product applications enhances reliability in the field of electronic commerce. The building of infrastructure and systems with advanced security functions is essential to prevent unauthorized access, and encryption technology is an important basic technology for the building of systems that realize these data security functions.
This handbook is mainly for system operators, systems integrators, systems engineers, and systems administrators concerned with system operations who incorporate encryption technology in systems. The objective is explanation of the necessary encryption knowledge and building methods for encryption systems in a manner that is easy to understand in order to realize security using encryption technologies.
Additionally, this handbook is a revised edition that adds tools for building encryption systems and other new information to the Encryption Utilization Technical Handbook published in March 1997.

This handbook has the following strengths.
- Forms of encryption usage are classified and explained in a manner that is easy to understand.
- The encryption systems are explained in a manner that is easy to understand without using formulas.
- Encryption safety focuses on the basic principle of safety evaluation and a safe encryption key size.
- Building of encryption systems and actual installation methods are explained along with key control systems, encryption libraries and tools, and the latest system architecture environments.
- The latest conditions concerning export restrictions on encryption products are explained for Japan and the United States, which require caution in the export and import of encryption products.

Data security includes the following four basic functions, and encryption technology is an important basic technology for realization of these security functions.
- Confidentiality: Guarantee that data is not leaked to third parties
- Integrity: Prevention of alteration of prepared data
- Authenticity: Guarantee that the ostensible preparer of the data is the real preparer
- Accountability: Checking of all processing in the past when errors occur and clear assignment of responsibility

Use of encryption in basic security functions, encrypted mail, Secure Sockets Layer (SSL), encrypted files, and other security application functions is explained, and widely used forms of encryption technology are described. Additionally, data concealment, the basic principle of electronically transparent technologies, used in protection of increasingly important intellectual property rights is also described.

Common key encryption, open key encryption, hash functions, random numbers, electronic transparency, and other encryption and data concealment devices and elemental technologies are described. Additionally, the primary examples of specific individual encryption methods are explained. Expected future technological advances and standardization, including trends in the Advanced Encryption Standard (AES), the next-generation encryption standard of the United States government, are also explained.

Control methods for encryption keys, which are during operation of systems that employ encryption are described. Key generation, update, revocation, other key lifecycles, key delivery methods, and control methods are explained. Additionally, typical key control systems and the advancing standardization operations of public key infrastructure (PKI) are also explained.

The importance of the problem open encryption algorithms is described in terms of safety of encryption, safety is evaluated in terms of decryption methods, and safe key lengths are described for representative encryption methods. Additionally, the international standard of security evaluation, Common Criteria (CC) is introduced in relation to safety evaluations of encryption.

Encryption system structuring methods, the latest conditions in encryption libraries and tools, and other building and installation methods necessary for building encryption systems are described. Additionally, verification of encryption functions and costs for using encryption are also described.

Including the direction of debate in international society, encryption policy problems, conditions concerning encryption import-export regulations in Japan and other countries, and other systems and laws concerning encryption are described.

This handbook describes the roles and usage forms of encryption technology, basic encryption technology, encryption key control methods, and other basic schemes of encryption and systems that employ encryption. The safety of encryption and its evaluation, and methods for building and installing encryption systems are also described. However, encryption technology is not as advanced as decryption technology, and it remains a new technology. Thus, it is important to fully heed cautions concerning worldwide trends in order to stay ahead of the curve.