[Federal Register Volume 64, Number 214 (Friday, November 5, 1999)]
[Notices]
[Pages 60424-60427]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-28947]


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DEPARTMENT OF COMMERCE

National Institute of Standards and Technology
[Docket No. 98109262-919-02]
RIN 0693-ZA 27


Announcing Approval of Federal Information Processing Standard 
(FIPS) 46-3, Data Encryption Standard

AGENCY: National Institute of Standards and Technology (NIST), 
Commerce.

ACTION: Notice.

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SUMMARY: The Secretary of Commerce has approved Federal Information 
Processing Standard (FIPS) 46-3, Data Encryption Standard, which 
supersedes FIPS 46-2. FIPS 46-3 provides for the use of the Triple DES 
as specified in American National Standard (ANSI) X9.52. NIST expects 
that Triple DES will provide Federal agencies with strong protective 
measures against associated risks until the Advanced Encryption 
Standard (AES) is available, probably in 2001.

EFFECTIVE DATE: This standard is effective March 25, 2000.

ADDRESSES: FIPS 46-3 is available on the NIST web page at: <http//
csrc.nist.gov/publications/drafts.html>.
    Copies of the ANSI X9.52 (Triple DES) standard are available from 
American Bankers Assoc./DC,X9 Customer Service Dept., P.O. Box 79064, 
Baltimore, MD 21279-0064, telephone 1-800-338-0626.
    Information on the Advanced Encryption Standard under development 
is available at: <http://www.nist.gov/aes>.

FOR FURTHER INFORMATION CONTACT: Ms. Elaine Barker, (301) 975-2911, 
National Institute of Standards and Technology, 100 Bureau Drive, STOP 
8930, Gaithersburg, MD 20899-8930.

SUPPLEMENTARY INFORMATION: Federal Information Processing Standard 46, 
Data Encryption Standard (DES), first issued in 1977, specified the 
Data Encryption algorithm, to be implemented in hardware devices, for 
the cryptographic protection of computer data. The standard provided 
that it be reviewed within five (5) years to assess its adequacy. In 
1981, the DES was adopted as an American National Standard and became 
widely used by the financial community. The first review of the DES was 
completed in 1983, and the DES was reaffirmed for Federal government 
use (48 FR 41062). The second review, completed in 1987, again resulted 
in the reaffirmation of the standard for Federal government use (52 FR 
7006). The standard was re-issued as FIPS 46-1 with minor editorial 
updating. The third review was completed in 1993, and the standard was 
reaffirmed as FIPS 46-2 for Federal government use (58 FR 69347). FIPS 
46-2 provided for software implementations, as well as hardware 
implementations, of the DES.

    When the DES was reaffirmed in 1993, NIST stated that it would 
``consider alternatives which offer a higher level of security'' at the 
next review in 1998. There was concern that the DES 56-bit key was not 
long enough to prevent an attack by trying all of the possible keys. 
NIST believed that the key was sufficiently long for the

[[Page 60425]]

expected life of the standard and that the security could be increased, 
when needed, by using the DES for three sequential encryption 
operations with different keys. This approach is called Triple DES. In 
1997, NIST advised Federal organizations that they could use Triple DES 
if they needed security beyond that provided by the DES.
    Since 1998, there have been reports that the DES could be attacked 
through an exhaustion attack whereby possible keys are tested one at a 
time until the correct key is found. Because of this, NIST proposed to 
replace FIPS 46-2 with FIPS 46-3 to specify use of Triple DES. Triple 
DES was documented and specified as an American National Standard (ANSI 
X9.52) by Accredited Standards Committee X9 for Financial Services, 
which develops cryptography and public key infrastructure standards. 
Triple DES was developed by the private sector with NIST assistance and 
is used by many government and private sector organizations, 
particularly in the financial services industry.
    Public comments were solicited on the draft of FIPS 46-3 in the 
Federal Register (January 15, 1999, Volume 64, Number 10, pp. 2625-
2628). The draft standard was also made available on NIST's web page. 
NIST received comments from three industry organizations and 
individuals and one Canadian government organization. The comments 
supported revision of the standard; minor technical and editorial 
changes were recommended and have been incorporated into FIPS 46-3.
    Related to FIPS 46-3 is NIST's project to develop an Advanced 
Encryption Standard (AES), anticipated for completion in 2001. It is 
anticipated that Triple DES and the Advanced Encryption Standard (AES) 
will coexist as FIPS approved algorithms allowing for a gradual 
transition to AES. (The AES is a new symmetric-based encryption 
standard under development by NIST. AES is intended to provide strong 
cryptographic security for the protection of sensitive information well 
into the 21st century.) NIST is working with industry and the 
cryptographic community to develop the AES, which will offer improved 
security and efficiency over Triple DES, and provide needed 
cryptographic protection will into the next century. Information on the 
AES is available at <http://www.nist.gov/aes>.

    Authority: This work effort is being conducted pursuant to 
NIST's responsibilities for the development of security standards 
and guidelines for the protection of sensitive federal information 
technology systems under the Computer Security Act of 1987, the 
Information Technology Management Reform Act of 1996, Executive 
Order 13011, and Appendix III to Office of Management and Budget 
(OMB) Circular A-130.

    Federal Information Processing Standards Publications (FIPS PUBS) 
are issued by the National Institute of Standards and Technology after 
approval by the Secretary of Commerce pursuant to Section 5131 of the 
Information Technology Management Reform Act of 1996 (Public Law 104-
106), and Computer Security Act of 1987 (Public Law 100-235).
    1. Name of Standard. Data Encryption Standard (DES).
    2. Catgegory of Standard. Computer Security, Cryptography.
    3. Explanation. The Data Encryption Standard (DES) specifies two 
FIPS approved cryptographic algorithms as required by FIPS 140-1. When 
used in conjunction with the American National Standards Institute 
(ANSI) X9.52 standard, this publication provides a complete description 
of the mathematical algorithms for encrypting (enciphering) and 
decrypting (deciphering) binary coded information. Encrypting data 
converts it to an unintelligible form called cipher. Decrypting cipher 
converts the data back to its original form called plaintext. The 
algorithms described in this standard specify both enciphering and 
deciphering operations that are based on a binary number called a key.
    A DES key consists of 64 binary digits (``0''s or ``1''s) of which 
56 bits are randomly generated and used directly by the algorithm. The 
other 8 bits, which are not used by the algorithm, may be used for 
error detection. The 8 error detecting bits are set to make the parity 
of each 8-bit byte of the key odd, i.e., there is an odd number of 
``1''s in each 8-bit byte.\1\ A TDEA key consists of three DES keys, 
which is also referred to as a key bundle. Authorized users of 
encrypted computer data must have the key that was used to encipher the 
data in order to decrypt it. The encryption algorithms specified in 
this standard are commonly known among those using the standard. The 
cryptographic security of the data depends on the security provided for 
the key used to encipher and decipher the data.
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    \1\ Sometimes keys are generated in an encrypted form. A random 
64-bit number is generated and defined to be the cipher formed by 
the encryption of a key using a key encrypting key. In this case the 
parity bits of the encrypted key cannot be set until after the key 
is decrypted.
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    Data can be recovered from cipher only by using exactly the same 
key used to encipher it. Unauthorized recipients of the cipher who know 
the algorithm but do not have the correct key cannot derive the 
original data algorithmically. However, it may be feasible to determine 
the key by a brute force ``exhaustion attack.'' Also, anyone who does 
have the key and the algorithm can easily decipher the cipher and 
obtain the original data. A standard algorithm based on a secure key 
thus provides a basis for exchanging encrypted computer data by issuing 
the key used to encipher it to those authorized to have the data.
    Data that is considered sensitive by the responsible authority, 
data that has a high value, or data that represents a high value should 
be cryptographically protected if it is vulnerable to unauthorized 
disclosure or undetected modification during transmission or while in 
storage. A risk analysis should be performed under the direction of a 
responsible authority to determine potential threats. The costs of 
providing cryptographic protection using this standard as well as 
alternative methods of providing this protection and their respective 
costs should be projected. A responsible authority then should make a 
decision, based on these analyses, whether or not to use cryptographic 
protection and this standard.
    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. This standard may be used by Federal departments 
and agencies when the following conditions apply:
    1. An authorized official or manager responsible for data security 
or the security of any computer system decides that cryptographic 
protection is required; and
    2. The data is not classified according to the National Security 
Act of 1947, as amended, or the Atomic Energy Act of 1954, as amended.
    Federal agencies or departments, which use cryptographic devices 
for protecting data classified according to either of these acts, can 
use those devices for protecting sensitive data in lieu of the 
standard.
    Other FIPS approved crytographic algorithms may be used in addition 
to or in lieu of this standard when implemented in accordance with FIPS 
140-1.
    In addition, this standard may be adopted and used by non-Federal 
Government organizations. Such use in encouraged when it provides the 
desired security for commercial and private organizations.

[[Page 60426]]

    7. Applications. Data encryption (cryptography) is utilized in 
various applications and environments. The specific utilization of 
encryption and the implementation of the DES and TDEA 2 will 
be based on many factors particular to the computer system and its 
associated components. In general, crytography is used to protect data 
while it is being communicated between two points or while it is stored 
in a medium vulnerable to physical theft. Communication security 
provides protection to data by enciphering it at the transmitting point 
and deciphering it at the receiving point. File security provides 
protection to data by enciphering it when it is recorded on a storage 
medium and deciphering it when it is read back from the storage medium. 
In the first case, the key must be available at the transmitter and 
receiver simultaneously during communication. In the second case, the 
key must be maintained and accessible for the duration of the storage 
period. FIPS 171 provides approved methods for managing the keys used 
by the algorithms specified in this standard. Public-key based 
protocols may also be used (e.g., ANSI X9.42).
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    \2\ DES forms the basis for TDEA.
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    8. Implementations. Crytographic modules that implement this 
standard shall conform to the requirements of FIPS 140-1. The 
algorithms specified in this standard may be implemented in software, 
firmware, hardware, or any combination thereof. The specific 
implementation may depend on several factors such at the application, 
the environment, the technology used, etc. Implementations which may 
comply with this standard include electronic devices (e.g., VLSI chip 
packages), micro-processors using Read Only Memory (ROM), Programmable 
Read Only Memory (PROM), or Electronically Erasable Read Only Memory 
(EEROM), and mainframe computers using Random Access Memory (RAM). When 
an algorithm is implemented in software or firmware, the processor on 
which the algorithm runs must be specified as part of the validation 
process. Implementations of an algorithm that are tested and validated 
by NIST will be considered as complying with the standard. Note that 
FIPS 140-1 places additional requirements on crytographic modules for 
Government use. Information about devices that have been validated and 
procedures for testing and validating equipment for conformance with 
this standard and FIPS 140-1 are available from the National Institute 
of Standards and Technology, Information Technology Laboratory, 100 
Bureau Dr. Stop 8930, Gaithersburg, MD 20899-8930.
    9. Export Control. Cryptographic devices and technical data 
regarding them are subject to Federal Government export controls and 
exports of cryptographic modules implementing this standard and 
technical data regarding them must comply with these Federal 
regulations and be licensed by the Bureau of Export Administration of 
the U.S. Department of Commerce.
    10. Patents. Cryptographic devices implementing this standard may 
be covered by U.S. and foreign patents, including patents issued to the 
International Business Machines Corporation. However, IBM has granted 
nonexclusive, royalty-free licenses under the patents to make, use and 
sell apparatus that complies with the standard. The terms, conditions 
and scope of the licenses are set out in notices published in the May 
13, 1975, and August 31, 1976, issues of the Official Gazette of the 
United States Patent and Trademark Office (934 O.G. 452 and 949 O.G. 
1717).
    11. Alternative Modes of Using the DES and TDEA. FIPS PUB 81, DES 
Modes of Operation, describes four different modes for using DES 
described in this standard. These four modes are called the Electronic 
Codebook (ECB) mode, the Cipher Block Chaining (CBC) mode, the Cipher 
Feedback (CFB) mode, and the Output Feedback (OFB) mode. ECB is a 
direct application of the DES algorithm to encrypt and decrypt data; 
CBC is an enhanced mode of ECB which chains together blocks of cipher 
text; CFB uses previously generated cipher text as input to the DES to 
generate pseudorandom outputs which are combined with the plain text to 
produce cipher, thereby chaining together the resulting cipher; OFB is 
identical to CFB except that the previous output of the DES is used as 
input in OFB while the previous cipher is used as imput in CFB. OFB 
does not chain the cipher.
    The ANSI X9.52 standard, ``Triple Data Encryption Algorithm Modes 
of Operation'' describes seven different modes for using TDEA described 
in this standard. These seven modes are called the TDEA Electronic 
Codebook Mode of Operation (TECB) mode, the TDEA Cipher Block Chaining 
Mode of Operation (TCBC), the TDEA Cipher Block Chaining Mode of 
Operation--Interleaved (TCBC-I), the TDEA Cipher Feedback Mode of 
Operation (TCFB), the TDEA Cipher Feedback Mode of Operation--Pipelined 
(TCFB-P), the TDEA Output Feedback Mode of Operation (TOFB), and the 
TDEA Output Feedback Mode of Operation--Interleaved (TOFB-I). The TECB, 
TCBC, TCFB and TOBF modes are based upon the ECB, CBC, CFB and OFB 
modes, respectively, obtained by substituting the DES encryption/
decryption operation with the TDEA encryption/decryption operation.
    12. Implementation of this standard. FIPS 46-3 supersedes FIPS 46-2 
on March 25, 2000. It applies to all Federal agencies, contractors of 
Federal agencies, or other organizations that process information 
(using a computer or telecommunications system) on behalf of the 
Federal Government to accomplish a Federal function. Each Federal 
agency or department may issues internal directives for the use of this 
standard by their operating units based on their data security 
requirement determinations.
    a. Triple DES (i.e., TDEA), as specified in ANSI X9.52, is 
recognized as a FIPS approved algorithm.
    b. Triple DES is the FIPS approved symmetric encryption algorithm 
of choice.
    c. Single DES (i.e., DES) is permitted for legacy systems only. New 
procurements to support legacy systems should, where feasible, use 
Triple DES products running in the single DES configuration.
    d. Government organizations with legacy DES systems are encouraged 
to transition to Triple DES based on a prudent strategy that matches 
the strength of the protective measures against the associated risk.

    Note: It is anticipated that triple DES and the Advanced 
Encryption Standard (AES) will coexist as FIPS approved algorithms 
allowing for a gradual transition to AES. (The AES is a new 
symmetric-based encryption standard under development by NIST. AES 
is intended to provide strong cryptographic security for the 
protection of sensitive information well into the 21st century.)

    NIST provides technical assistance to Federal agencies in 
implementing data encryption through the issuance of standards, 
guidelines and through individual reimbursable projects.
    13. Specifications. Federal Information Processing Standard (FIPS) 
46-3, Data Encryption Standard (DES) (affixed).
    14. Cross Index.
    a. FIPS PUB 31, Guidelines to ADP Physical Security and Risk 
Management.
    b. FIPS PUB 39, Glossary for Computer Systems Security.
    c. FIPS PUB 73, Guidelines for Security of Computer Applications.
    d. FIPS PUB 74, Guidelines for Implementing and Using the NBS Data 
Encryption Standard.
    e. FIPS PUB 81, DES Modes of Operation.

[[Page 60427]]

    f. FIPS PUB 87, Guidelines for ADP Contingency Planning.
    g. FIPS PUB 112, Password Usage.
    h. FIPS PUB 113, Computer Data Authentication.
    i. FIPS PUB 140-1, Security Requirements for Cryptographic Modules.
    j. FIPS PUB 171, Key Management Using ANSI X9.17.
    k. ANSI X9.42, Agreement of Symmetric Keys on Using Discrete 
Logarithm Cryptography.
    l. ANSI X9.52, Triple Data Encryption Algorithm Modes of Operation.
    15. Qualifications. Both this standard and possible threats 
reducing the security provided through the use of this standard will 
undergo review by NIST as appropriate, taking into account newly 
available technology. In addition, the awareness of any breakthrough in 
technology or any mathematical weakness of the algorithm will cause 
NIST to reevaluate this standard and provide necessary revisions.
    With regard to the use of single DES, exhaustion of the DES (i.e., 
breaking a DES encrypted ciphertext by trying all possible keys) has 
become increasingly more feasible with technology advances. Following a 
recent hardware based DES key exhaustion attack, NIST can no longer 
support the use of single DES for many applications.
    16. Comments. Comments and suggestions regarding this standard and 
its use are welcomed and should be addressed to the National Institute 
of Standards and Technology, Attn: Director, Information Technology 
Laboratory, 100 Bureau Dr., Stop 8900, Gaithersburg, MD 20899-8900.
    17. Waiver Procedure. Under certain exceptional circumstances, the 
heads of Federal departments and agencies may approve waivers to 
Federal Information Processing Standards (FIPS). The head of such 
agency may redelegate such authority only to a senior official 
designated pursuant to section 3506(b) of Title 44, United States Code. 
Waiver shall be granted only when:
    a. Compliance with a standard would adversely affect the 
accomplishment of the mission of an operator of a Federal computer 
system; or
    b. Compliance with a standard would cause a major adverse financial 
impact on the operator that is not offset by Government-wide savings.
    Agency heads may act upon a written waiver request containing the 
information detailed above. Agency heads may also act without a written 
waiver request when they determine that conditions for meeting the 
standard cannot be met. Agency heads may approve waivers only by a 
written decision that explains the basis on which the agency head made 
the required finding(s). A copy of each decision, with procurement 
sensitive or classified portions clearly identified, shall be sent to 
National Institute of Standards and Technology; ATTN: FIPS Waiver 
Decisions, 100 Bureau Drive, Stop 8930, Gaithersburg, MD 20899-8930.
    In addition, notice of each waiver granted and each delegation of 
authority to approve waivers shall be sent promptly to the Committee on 
Government Operations of the House of Representatives and the Committee 
on Government Affairs of the Senate and shall be published promptly in 
the Federal Register.
    When the determination on a waiver applies to the procurement of 
equipment and/or services, a notice of the waiver determination must be 
published in the Commerce Business Daily as a part of the notice of 
solicitation for offers of an acquisition or, if the waiver 
determination is made after that notice is published, by amendment to 
such notice.
    A copy of the waiver, any supporting documents, the document 
approving the waiver and any accompanying documents, with such 
deletions as the agency is authorized and decides to make under 5 
United States Code Section 552(b), shall be part of the procurement 
documentation and retained by the agency.
    18. Special Information. In accordance with the Qualifications 
Section of this standard, reviews of this standard have been conducted 
every 5 years since its adoption in 1977. The standard was reaffirmed 
during each of those reviews. This revision to the text of the standard 
contains changes which allow software implementations of the algorithm, 
permit the use of other FIPS approved cryptographic algorithms, and 
designate Triple DES (i.e., TDEA) as a FIPS approved cryptographic 
algorithm.
    19. Where to Obtain Copies of the Standard. Copies of this 
publication are for sale by the National Technical Information Service, 
U.S. Department of Commerce, Springfield, VA 22161. When ordering, 
refer to Federal Information Processing Standards Publication 46-3 
(FIPSPUB46-3), and identify the title. When microfiche is desired, this 
should be specified. Prices are published by NTIS in current catalogs 
and other issuances. Payment may be made by check, money order, deposit 
account or charged to a credit card accepted by NTIS.

    Dated: October 29, 1999.
Karen H. Brown,
Deputy Director, NIST
[FR Doc. 99-28947 Filed 11-4-99; 8:45 am]
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