DATA ENCRYPTION STANDARD DES

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DATA ENCRYPTION STANDARD (DES)


Abstract
The selective application of technological and related procedural safeguards is an important responsibility of every Federal organization in providing adequate security to its electronic data systems. This publication specifies two cryptographic algorithms, the Data Encryption Standard (DES) and the Triple Data Encryption Algorithm (TDEA) which may be used by Federal organizations to protect sensitive data. Protection of data during transmission or while in storage may be necessary to maintain the confidentiality and integrity of the information represented by the data. The algorithms uniquely define the mathematical steps required to transform data into a cryptographic cipher and also to transform the cipher back to the original form. The Data Encryption Standard is being made available for use by Federal agencies within the context of a total security
program consisting of physical security procedures, good information management practices, and computer system/network access controls. This revision supersedes FIPS 46-2 in its entirety.


Key words: computer security, data encryption standard, triple data encryption algorithm, Federal
Information Processing Standard (FIPS); security.


Announcing the
DATA ENCRYPTION STANDARD
1. Name of Standard. Data Encryption Standard (DES).
2. Category of Standard. Computer Security, Cryptography.
3. Explanation.
4. Approving Authority. Secretary of Commerce.
5. Maintenance Agency. U.S. Department of Commerce, National Institute of Standards and
Technology, Information Technology Laboratory.
6. Applicability.
7. Applications.
8. Implementations.
9. Export Control.
11. Alternative Modes of Using the DES and TDEA.
12. Implementation of this standard.
13. Specifications. Federal Information Processing Standard (FIPS) 46-3, Data Encryption
Standard (DES) (affixed).
14. Cross Index.
15. Qualifications.
16. Comments.
17. Waiver Procedure.
18. Special Information.
19. Where to Obtain Copies of the Standard.
SPECIFICATIONS FOR THE
DATA ENCRYPTION STANDARD (DES)
DATA ENCRYPTION ALGORITHM
Introduction
Enciphering
Deciphering
The Cipher Function f
TRIPLE DATA ENCRYPTION ALGORITHM
APPENDIX 1
PRIMITIVE FUNCTIONS FOR THE
DATA ENCRYPTION ALGORITHM
APPENDIX 2
TRIPLE DES BLOCK DIAGRAM
(ECB Mode)
TDEA Encryption Operation: