[Federal Register Volume 62, Number 177 (Friday, September 12, 1997)]
[Notices]
[Pages 48051-48058]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24214]



[[Page 48051]]

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DEPARTMENT OF COMMERCE

National Institute of Standards and Technology
[Docket No. 970725180-7180-01]
RIN No. 0693-ZA16


Announcing Request for Candidate Algorithm Nominations for the 
Advanced Encryption Standard

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

ACTION: Notice; Request for candidate encryption algorithm nomination 
packages.

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SUMMARY: A process to develop a Federal Information Processing Standard 
(FIPS) for Advanced Encryption Standard (AES) specifying an Advanced 
Encryption Algorithm (AEA) has been initiated by the National Institute 
of Standards and Technology (NIST). This notice requests submission of 
candidate algorithms for consideration for inclusion in the AES and 
specifies how to submit a nomination package. The requirements for 
candidate algorithm submission packages and minimum acceptability 
requirements that must be satisfied in order to be deemed a ``complete 
and proper'' submission are presented. the evaluation criteria which 
will be used to appraise the candidate algorithms are also described.
    It is intended that the AES will specify an unclassified, publicly 
disclosed encryption algorithm available royalty-free worldwide that is 
capable of protecting sensitive government information well into the 
next century.

    The purpose of this notice is to solicit candidate algorithms from 
the public, academic/research communities, manufacturers, voluntary 
standards organizations, and Federal, state, and local government 
organizations. Following the close of the submission period, NIST 
intends to make all submissions publicly available for review and 
comment.

DATES: Submission deadline: Candidate algorithm nomination packages 
must be received by June 15, 1998.
    Submission packages received before April 15, 1998, will be 
reviewed for completeness by NIST and notified of their specific 
deficiencies, if any, by May 15, 1998, allowing time for deficient 
packages to be amended by the submission deadline.
    No amendments to deficient packages will be permitted after the 
submission deadline. Requests for withdrawal of candidate algorithm 
submission packages previously submitted will only be honored until the 
submission deadline.

ADDRESSES: Candidate algorithm submission packages should be send to 
Director, Information Technology Laboratory, Attn: Advanced Encryption 
Standard Nominations, Technology Building, Room A231, National 
Institute of Standards and Technology, Gaithersburg, MD 20899.

FOR FURTHER INFORMATION CONTACT:
For general information, contact: Edward Roback, National Institute of 
Standards and Technology, Building 820, Room 426, Gaithersburg, MD 
20899; telephone 301-975-3696 or via fax at 301-948-1233.
    If necessary, general questions for clarification of these 
requirements for candidate algorithm submission packages, minimum 
acceptability requirements, or evaluation criteria/process should be 
sent electronically to <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="dd9c988e8c88988e899d93948e89f39a928b">[email protected]</a> or via fax to 301-948-1233 
(Attn: AES Questions). In fairness to all parties, answers to germane 
questions will be made publicly available simultaneously to all those 
interested at <http://csrc.nist.gov/encryption/aes>. Non-pertinent 
questions may be ignored.
    Technical questions and questions related to a specific submission 
package may be made by contacting either Miles Smid at (301) 975-2938, 
or Jim Foti at (301) 975-5237.
    NIST will endeavor to answer all questions in a timely manner.

SUPPLEMENTARY INFORMATION: This section contains the following:

1. Background
2. Requirements for Candidate Algorithm Submission Packages
    2.A Cover sheet
    2.B Algorithm Specifications and Supporting Documentation
    2.C Magnetic media
    2.D Intellectual property statements/agreements/disclosures
    2.E General Submission Requirements
3. Minimum Acceptability Requirements
4. Evaluation Criteria
5. First AES Conference
6. Plans for Candidate Evaluation Process
    6.A Overview
    6.B Round 1 Technical Evaluation
    6.C Round 2 Technical Evaluation
7. Miscellaneous

1. Background

    This work effort is being initiated pursuant to NIST's 
responsibilities under the Computer Security Act of 1987, the 
Information Technology Management Reform Act of 1996, Executive Order 
13011, and OMB Circular A-130.
    NIST recognizes that many institutions, both within and outside the 
Federal Government, have considerable investments in their current 
installed base of encryption equipment implementing the Data Encryption 
Algorithm, specified in the Data Encryption Standard (DES, Federal 
Information Processing Standard 46-2). DES was first approved in 1977 
and was most recently reaffirmed by the Secretary in 1993, until 
December 1998. In 1993 the following statement was included in the 
standard:

    At the next review (1998), the algorithm specified in this 
standard will be over twenty years old. NIST will consider 
alternatives which offer a high level of security. One of these 
alternatives may be proposed as a replacement standard at the 1998 
review.

    It is NIST's view that a multi-year transition period will be 
necessary to move toward any new encryption standard and the DES will 
continue to be of sufficient strength for many applications. NIST will 
consult with all interested parties so that a smooth transition can be 
accomplished. NIST may not complete the AES selection process before 
the end of its 1998 DES Review, and an interim solution(s) may be 
necessary.
    For interoperability and other purposes, NIST strongly desires to 
select a single block encryption algorithm to be specified in the AES 
with a strength equal to or better than that of Triple DES and 
significantly improved efficiency. However, if more than one suitable 
candidate is identified which provides significantly better advantages 
in a specific application(s), NIST may consider recommending more than 
one algorithm. Present resource constraints do not permit the 
development of a specific standard algorithm for 8-bit smart card 
implementations or a standard stream cipher. It is hoped that the block 
cipher selected will be suitably flexible for a wide variety of 
implementations, recognizing that it may not operate with optimal 
efficiency in each and every potential application.

2. Requirements for Candidate Algorithm Submission Packages

    To be considered as a ``complete'' nomination package (and continue 
further in the AES consideration process), candidate algorithm 
submission packages MUST contain the following (as described in detail 
below):

Cover sheet
Algorithm Specifications and Supporting Documentation
Magnetic media
Intellectual property statements/agreements/disclosures


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    Each of these is discussed in detail below, including ``general 
submission requirements'' which all nominations must also satisfy.

2.  A  Cover sheet

    A cover sheet containing the following information:

Name of submitted algorithm
Principal submitter's name, telephone, fax, organization, postal 
address, e-mail address
Name(s) of auxiliary submitter(s)
Name of algorithm inventor(s) developer(s)
Name of owner, if any, of the algorithm. (normally expected to be the 
same as the submitter)
Signature of Submitter (optional) Backup point of contact (w/telephone, 
fax, postal address, e-mail)

2.B  Algorithm Specifications and Supporting Documentation

    2.B.1  A complete written specification of the algorithm shall be 
included, consisting of all necessary mathematical equations, tables, 
diagrams, and parameters that are needed to implement the algorithm. 
The submission of all design rationale (e.g., method for generating 
table values, rationale for number of rounds, etc.) is strongly 
encouraged, in order to facilitate the public evaluation process.
    Parity bits shall not be specified in the key definition. The bit 
naming/numbering convention for the key shall be provided by the 
submitter.
    2.B.2  A statement of the algorithm's estimated computational 
efficiency in hardware and software shall be included. At a minimum, 
the submitter shall state efficiency estimates for the ``NIST AES 
analysis platform'' (specified elsewhere in section 6.B) and for 8-bit 
processors. (Efficiency estimates for other platforms may be included 
at the submitters' discretion.) These estimates shall each include the 
following information, at a minimum:
    a. Description of the platform used to generate the estimate, in 
sufficient detail so that the estimates could be verified in the public 
evaluation process (e.g., for software running on a PC, include 
processor, clock speed, memory, operating system, etc.). For hardware 
estimates, it is encouraged that a gate count (or estimated gate count) 
be included.
    b. Speed estimate for the algorithm on the platform specified in 
section 6.B. At a minimum, the number of clock cycles required to

(1) encrypt one block of data,
(2) decrypt one block of data,
(3) setup a key,
(4) setup the algorithm (e.g., build internal tables), and
(5) change a key after its initial setup

shall be specified for each key- and block-size combination required in 
the Minimum Acceptability Requirements section of this announcement.
    c. Any available information on tradeoffs between speed and memory.
    2.B.3 A series of Known Answer Tests (KATs) and Monte Carlo Tests 
(MCTs) shall be included as specified below. All of these KAT and MCT 
values shall be submitted electronically, in separate files, on a 
diskette as described in section 2.C.3. (The files containing test 
values may be compressed using PKZIP or GNUZIP to conserve disk space.) 
Each file shall be clearly labeled with header information listing: (1) 
Algorithm name, (2) Test name, (3) Description of the test, and (4) 
Key-block size combination being tested. All values within the file 
shall be clearly labeled (e.g., index, key, plaintext, ciphertext, 
etc.), and shall be in the exact format specified by NIST on its WWW 
site at <http://csrc.nist.gov/encryption/aes>.
    a. All applicable KATs shall be included that can be used to 
exercise various features of the algorithm when operated in the 
Electronic Codebook (ECB) mode. A set of KATs shall be included for 
each key and block size specified in the Minimum Acceptability 
Requirements section. Required KATs include:
    i. Variable Key Known Answer Test--A variable key KAT is required 
for the algorithm's encryption state. For an n-bit key size, there 
shall be n key-plaintext-ciphertext triples. The plaintext shall always 
consist entirely of binary zeros; the key shall always contain a single 
`1' bit and n-1 `0' bits, and the n possible keys (where each key has 
the `1' bit in a different position) shall be used to generate 
ciphertext. (To run this test for decryption, the ciphertext should be 
used as input to recover the block of all zero bits, for each possible 
one-bit key.)
    ii. Variable Plaintext Known Answer Test--A variable plaintext KAT 
is required for the algorithm's encryption state. For an m-bit block 
size, there shall be m kep-plaintext-ciphertext triples. The key shall 
always consist entirely of binary zeros; the plaintext block shall 
always contain a single `1' bit and m-1 `0' bits, and the m possible 
blocks (where each input block has the `1' bit in a different position) 
shall be used to generate ciphertext. (To run this test for decryption, 
the ciphertext should be used as input to recover the correct input 
block, using the key consisting only of `0' bits.)
    iii. If the candidate algorithm calculates intermediate values 
(e.g., internal rounds) for an encryption or decryption operation, then 
the submitter shall include known answers for those intermediate values 
for a single encryption and decryption operation for each of the 
required key- and block-size combinations.
    iv. If tables are used in the algorithm, then a known answer test 
shall be included to exercise every table entry.

    Note: The submitter may include any other known answer tests 
that exercise different features of the algorithm (e.g., for 
permutation tables, etc.). The purposes of these tests shall be 
clearly described in the file containing the test values.

    b. Four Monte Carlo Tests shall be included, with key and data 
values, for each of the key-block combinations required in the Minimum 
Acceptability Requirements section. These four tests correspond with 
tests specified in the NIST Special Publication, Modes of Operation 
Validation System: Requirements and Procedures [MOVS]. The four tests 
required for the AES submissions correspond with the two Electronic 
Codebook Modes Tests for encryption and decryption (Sections 5.1.1.5 
and 5.1.2.5 in [MOVS]) the two Cipher Block Chaining Modes Tests for 
encryption and decryption (Sections 5.2.1.5 and 5.2.2.5 in [MOVS]).
    A link to a description of the required tests will be available at 
<http://csrc.nist.gov/encryption/aes>. Required submission data for the 
Monte Carlo Tests will also be found at that location.
    2.B.4  A statement of the expected strength (i.e. workfactor) of 
the algorithm shall be included, along with any supporting rationale. 
The expected strength shall be given for each key- and block-size 
combination required in the minimum Acceptability Requirements section 
of this announcement, and for all other key- and block-size 
combinations claimed to be supported by the algorithm.
    2.B.5  An analysis of the algorithm with respect to known attacks 
(e.g., known and chosen plaintext) shall be included. In addition, all 
known weak keys, equivalent keys, complementation properties, 
restrictions on key selection, and other similar features of the 
algorithm shall be noted by the submitter. If no such values are known, 
then this shall be stated by the submitter.
    The submitter should provide any mathematical rationale for the 
non-existence of ``trap-doors'' in the algorithm, to the greatest 
extent possible.
    The submitter shall provide a list of known references to any 
published

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materials describing or analyzing the security of the submitted 
algorithm. Submission of copies of these materials (accompanied by a 
waiver of copyright or permission from the copyright holder for AES 
public evaluation purposes) is encouraged.
    2.B.6  A statement shall be included that lists and describes 
advantages and limitations of the algorithm. Such advantages and 
limitations shall address the ability to:
    a. implement the algorithm as a stream cipher, Message 
Authentication Code (MAC) generator, pseudo-random number generator, 
hashing algorithm, etc.
    b. implement the algorithm in various environments, including--but 
not limited to: 8-bit processors (smartcards), ATM, HDTV, B-ISDN, voice 
applications, satellite applications, etc. To demonstrate the 
efficiency of a hardware implementation of the algorithm, the submitter 
may include a specification of the algorithm in a nonproprietary 
Hardware Description Language (HDL).
    c. use the algorithm with key- and block-sizes other than those 
required as a minimum in the Minimum Acceptability Requirements section 
of this announcement.
    If the submitter believes that the algorithm has certain features 
deemed advantageous by the submitter, then these should be listed and 
described, along with supporting rationale. Some examples of these 
features might include, for example: throw-away tables, mathematically 
(rather than empirically) designed tables, statistical basis for inter-
round mixing, variable key setup time, etc.

2.C  Magnetic Media

2.C.1  Reference Implementation
    A reference implementation shall be submitted, in order to promote 
the understanding of how the candidate algorithm may be implemented. 
This implementation shall consist of source code written in ANSI C; 
appropriate comments should be included in the code, and it should 
clearly map to the algorithm description included under section 2.B.1. 
Since this implementation is intended for reference purposes, clarity 
in programming is more important than efficiency.
    The reference implementation shall be capable of fully 
demonstrating the operation of the candidate algorithm. The reference 
implementation shall support all key- and block-size combinations 
specified in the Minimum Acceptability Requirements section of this 
announcement. Additionally, it must support all other key-block sizes 
that are claimed to be supported by the algorithm.
    NIST will specify a cryptographic API for the ANSI C 
implementations, which will be made available at <<a href="http://csrc.nist.gov/
encryption/aes">http://csrc.nist.gov/
encryption/aes</a>>. All ANSI C submissions shall implement that API, so 
that the NIST test system can be compatible with all submissions.
    Separate source code for implementing the required Known Answer 
Tests and Modes Tests with the reference implementation shall also be 
included. This code shall be able to process input specified in the 
format indicated by NIST (on the WWW site as referred to under section 
2.B.3) and run the required tests.
    The reference implementation shall be provided on a single 
diskette, which shall be labeled with the submitter's name, the 
algorithm name, and ``Reference Implementation.''
2.C.2  Mathematically Optimized Implementation
    Two mathematically optimized implementations of the candidate 
algorithm shall be submitted, so that NIST can perform tests in two 
different languages in order to demonstrate the potential for efficient 
implementation. These two implementations shall be specified in ANSI C 
and Java programming languages:
    i. ANSI C: The first mathematically optimized implementation shall 
be specified in ANSI C source code. NIST intends to use the ANSI C 
compiler specified under ``Round 1 Technical Analysis'' to compile the 
code and link it to the NIST test system. (NIST received many comments 
that the optimized implementation should be written in C, since it is a 
very common language.)
    NIST will specify a cryptographic API for the ANSI C 
implementations, which will be made available at <<a href="http://csrc.nist.gov/
encryption/aes">http://csrc.nist.gov/
encryption/aes</a>>. All ANSI C submissions shall implement that API, so 
that the NIST test system can be compatible with all submissions.
    ii. Java language specification: The second mathematically 
optimized implementation shall be specified in the Java programming 
language, as defined by the Java Development Kit (JDK) version 1.1. 
This JDK 1.1 is publicly available for multiple platforms from 
Javasoft, at <http://www.javasoft.com>. NIST has selected Java as one 
language for the mathematically optimized implementations because it 
will provide an accurate relative mathematical efficiency measure of 
the different candidate algorithms, since it uses machine-independent 
code. The use of one Java Virtual Machine--to test all of the Java 
implementations submitted to NIST--is intended to eliminate differences 
in hardware optimizations that may occur when using other languages. It 
is not intended that the Java implementation will provide an absolute 
efficiency measure of each candidate algorithm on the NIST Analysis 
Platform.
    Submissions are required to use the cryptographic API defined by 
the Java Cryptography Architecture (JCA) in conjunction with the Java 
Cryptography Extension (JCE). An AES submitter shall create a 
Cryptography Package Provider (CPP) that implements the submitted 
candidate algorithm. The Provider class is described in the JCA (Refer 
to <http://java.sun.com:80/products/jdk/1.1/docs/guide/security/
CryptoSpec.html>, under ``The Provider Class''; JCE 1.1 APIs may be 
found at <http://java.sun.com/security>). The ``Cipher'' engine 
subclass within the CPP (as defined in the JCE) shall then be used to 
implement the candidate encryption algorithm. Other appropriate engine 
subclasses from the JCA and JCE may also be implemented, to accommodate 
features of the particular candidate algorithm (e.g., ``Key Generator'' 
class in the JCE).

General Requirements for Both Mathematically Optimized Implementations

    Both of the mathematically optimized implementations shall support 
key- and block-size combinations specified in the Minimum Acceptability 
Requirements section of this announcement.
    The mathematically optimized implementations shall operate in the 
Electronic Codebook (ECB), Cipher Block Chaining (CBC), and 1-bit 
Cipher Feedback (1-CFB) modes for encryption and decryption. Other 
modes are not required to be implemented in the software provided to 
NIST.
    Separate source code for implementing the required Known Answer 
Tests and Modes Tests with the mathematically optimized implementations 
shall also be included. This code shall be able to process input 
specified in the format indicated by NIST (on the WWW site as referred 
to under section 2.B.3) and run the required tests.
    The submitter shall provide the mathematically optimized 
implementations on two separate diskettes, which shall be labeled with 
the submitter's name, the algorithm name, and ``Optimized--ANSI C'' or 
``Optimized--Java''.
    Additionally, submitters may, at their discretion, submit revised 
optimized

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implementations (for both the ANSI C and Java implementations) for use 
in the Round 2 evaluation process, allowing additional time for 
improvements. These must be received prior to the beginning of the 
round 2 evaluation; submittors will be notified of the specific 
deadline as appropriate. Note that the mathematically optimized 
implementations on file with NIST at the close of the initial 
submission period will be the ones used in the Round 1 evaluation.
2.C.3  Test Values--Known Answer Tests and Monte Carlo Tests
    The files on this diskette shall contain all of the test values 
required under section 2.B.3 of this announcement. That section 
includes descriptions of the required tests as well as a list of the 
values that must be provided. These files may be compressed using PKZIP 
or GNUZIP to conserve disk space, if necessary.
    The required format for the test vectors will be specified by NIST 
at <http://csrc.nist.gov/encryption/aes>
    The test values shall be provided on a single diskette, which shall 
be labeled with the submitter's name, the algorithm name, and ``Test 
Values: Known Answer Tests and Monte Carlo Tests.''
2.C.4  Supporting Documentation
    So as to facilitate electronic distribution of submissions to all 
interested parties, copies of all written materials must also be 
submitted in electronic form in either PostScript or Adobe PDF. PDF is 
preferable. (NIST will convert PostScript submissions to PDF.) 
Submitters planning to create PDF are encouraged to use the thumbnail 
and bookmark features, to have a clickable table of contents (if 
applicable), and to include other links within the PDF as appropriate. 
To create a PostScript file, users of PC word processors should 
configure their software to print using a PostScript printer driver, 
and capture the output using the ``print to file'' feature, preferably 
using standard PostScript printer fonts (not downloaded fonts).
    Users of TeX, LaTeX/DVIPS should use PostScript Type 1 fonts, 
preferably standard PostScript printer fonts, rather than the default 
embedded bitmapped Computer Modern fonts. Instructions for configuring 
DVIPS can be found at <<a href="http://www.adobe.com/supportservice/custsupport/
SOLUTIONS/385e.htm">http://www.adobe.com/supportservice/custsupport/
SOLUTIONS/385e.htm</a>>, ``Creating quality Adobe PDF files from TeX with 
DVIPS,'' by Kendall Whitehouse/EMERGE, FaxYI number 131303. (This is 
cited for reference purposes only, and does not constitute a direct or 
implied endorsement.)
    NIST then intends to make submissions available electronically 
(consistent with U.S. export regulations) in both PostScript and PDF 
formats.
    This electronic version of the supporting documentation shall be 
provided on diskette(s), which shall be labeled with the submitter's 
name, the algorithm name, and ``Supporting Documentation.'' If multiple 
diskettes are necessary, each diskette must also be labeled with ``#m 
of n'' as appropriate.
2.C.5  General Requirements for Magnetic Media
    A separate diskette shall be used for the reference implementation, 
mathematically optimized implementations, test values, and supporting 
materials.
    All magnetic media presented to NIST shall be free of viruses or 
other malicious code. Media submitted will be scanned for the presence 
of such code. If such malicious code is found, NIST will notify the 
submitter and ask that a clean version of the magnetic media be re-
submitted.
    All magnetic media shall be submitted on 3.5'' 1.44MB floppy 
diskettes, formatted for use on an IBM-compatible PC.
    A file labeled ``README'' shall be included on each diskette, 
listing all files included on the diskette, with a brief description of 
each.
    NIST is in the process of defining a selected set of cryptographic 
service calls for the ANSI C implementations. For the Java 
implementation, NIST will use calls from the Java Cryptography 
Architecture API. These two sets of calls shall be used by the NIST 
test software to make appropriate calls to the optimized and reference 
implementations, so that the test software does not have to be 
rewritten for each submitted algorithm. Therefore, both the 
mathematically optimized and reference implementations are required to 
conform with these specific calls. The implementations shall be 
supplied in source code so that NIST can compile and link them 
appropriately with the test software. The two selected sets of required 
calls will be available at the following location: <<a href="http://
csrc.nist.gov/encryption/aes">http://
csrc.nist.gov/encryption/aes</a>>. NIST intends that these will be 
available within three months after publication of this notice.

2.D  Intellectual Property Statements/Agreements/Disclosures

    After review of the public comments on the draft minimum 
acceptability requirements and evaluation criteria (published for 
comment in the Federal Register on January 2, 1997), NIST has 
determined that potential users of the AES desire to have the AES 
available worldwide on a royalty free basis. Additionally, based upon 
the results of the April 15, 1997 public workshop held on the draft 
evaluation criteria and submission requirements, NIST believes there is 
a reasonable basis to expect a sufficient number and variety of 
submissions willing to meet these licensing conditions such that the 
expressed needs of potential AES users can be accommodated.
    In order to ensure this and minimize any intellectual property 
issues, the following statement is required:
2.D.1  Statement by the Submitter
    I, ________ (print submitter's full name) ________ do hereby 
declare that to the best of my knowledge the practice of the algorithm, 
reference implementation, and mathematically optimized implementations, 
I have submitted, known as ________ (print name of algorithm) ________ 
may be covered by the following U.S. and/or foreign patents: ________ 
(describe and enumerate or state ``none'' if appropriate) ________.
    I do herby declare that I am aware of no patent applications which 
may cover the practice of my submitted algorithm, reference 
implementation or mathematically optimized implementations. -OR- I do 
hereby declare that the following pending patent applications may cover 
the practice of my submitted algorithm, reference implementation or 
mathematically optimized implementations: ________ (describe and 
enumerate) ________.
    I do hereby understand that my submitted algorithm may not be 
selected for inclusion in the Advanced Encryption Standard. I also 
understand and agree that after the close of the submission period, my 
submission may not be withdrawn from public consideration for inclusion 
in the Federal Information Processing Standard (FIPS) for Advanced 
Encryption Standard (AES). I further understand that I will not receive 
financial compensation from the government for my submission. I certify 
that, to the best of my knowledge, I have fully disclosed all patents 
and patent applications relating to my algorithm. I also understand 
that the U.S. Government may, during the course of the lifetime of the 
AES or during the FIPS public review process, modify the algorithm's 
specifications (e.g., to protect against a newly discovered 
vulnerability). Should my submission be

[[Page 48055]]

selected for inclusion in the AES, I hereby agree not to place any 
restrictions on the use of the algorithm intending it to be available 
on a worldwide, non-exclusive, royalty-free basis.
    I do hereby agree to provide the statements required by sections 
2.D.2 and 2.D.3, below, for any patent or patent application identified 
to cover practice of my algorithm, reference implementation or 
mathematically optimized implementations and the right to use such 
implementation for the purposes of the AES evaluation process.
    I understand that NIST will announce the selected algorithm(s) and 
proceed to publish the draft FIPS for public comment. If my algorithm 
(or the derived algorithm) is not selected for inclusion in the FIPS 
(including those not selected for second round of public evaluation), I 
understand that all rights, including use rights of the reference and 
mathematically optimized implementation, revert back to the submitter 
(and other owner[s] as appropriate). Additionally, should the U.S. 
Government not select my algorithm for inclusion in the AES after a 
period of four years from the close of the submission date for 
candidate algorithms, all rights revert to the submitter (and other 
owner[s] as appropriate).

Signed:
Title:
Dated:
Place:
2.D.2  Statement by Patent (and Patent Application) Owner(s)
    If there are any patents (or patent applications) identified by the 
submitter, including those held by the submitter, the following 
statement must be signed by each and every owner of the patent and 
patent applications above identified.
    I, ________ (print full name) ________, of ________ (print full 
postal address) ________, am the owner or authorized representative of 
the owner (print full name, ________ if different than ________ the 
signer) of the following patent(s) and or ________ patent 
application(s): ________ (enumerate) ________, and do hereby agree to 
grant to ________ any interested party if the algorithm known as 
________ (print name of algorithm ________, is selected for inclusion 
in the Advanced Encryption Standard, an irrevocable nonexclusive 
royalty-free license to practice the referenced algorithm, reference 
implementation or the mathematically optimized implementations. 
Furthermore, I agree to grant the same rights in any other patent 
granted to me or my company which may be necessary for the practice of 
the referenced algorithm, reference implementation, or the 
mathematically optimized implementations.

Signed:
Title:
Dated:
Place:

    Note that the government may conduct research as may be appropriate 
to verify the availability of the submission of a royalty free basis 
worldwide.
2.D.3  Statement by Reference/Mathematically Optimized Implementations' 
Owner(s)
    The following must also be included:
    I, ________ (print full name) ________, am the owner of the 
submitted reference implementation and mathematically optimized 
implementations and hereby grant the Government and any interested 
party the right to use such implementations for the purposes of the AES 
evaluation process notwithstanding that the implementations may be 
copyrighted.

Signed:
Title:
Dated:
Place:

2.E  General Submission Requirements

    NIST welcomes both domestic and international submissions; however, 
in order to facilitate analysis and evaluation, it is required that the 
submission packages be in English. This information includes the cover 
sheet, algorithm specification and supporting documentation, source 
code, and intellectual property information. Any required information 
that is submitted in a language other than English shall render the 
submission package ``incomplete.'' Optional supporting materials (e.g., 
journal articles) in another language may be submitted.
    Classified and/or proprietary submissions shall not be accepted.

3. Minimum Acceptability Requirements

    Those packages which are deemed to be ``complete'' will then be 
evaluated to see if they contain a ``proper'' candidate algorithm. To 
be considered as a ``proper'' candidate algorithm submissions (and 
continue further in the AES Development Process), candidate algorithms 
must meet the following minimum acceptability requirements:
    1. The algorithm must implement symmetric (secret) key 
cryptography.
    2. The algorithm must be a block cipher.
    3. The candidate algorithm shall be capable of supporting key-block 
combinations with sizes of 128-128, 192-128, and 256-128 bits. A 
submitted algorithm may support other key-block sizes and combinations, 
and such features will be taken into consideration during analysis and 
evaluation.
(End of minimum acceptability requirements)

    Candidate algorithm submission packages which are complete (as 
defined earlier) and whose algorithm meets the minimum acceptability 
requirements (as defined immediately above) will be deemed to be 
``complete and proper'' submissions. Those deemed otherwise will 
receive no further consideration. A complete list of submissions will 
be publicly announced by NIST--those which are ``complete and proper,'' 
and any others.

4. Evaluation Criteria

    In order to provide a basis for the analysis and evaluation of 
encryption algorithms submitted to be considered for incorporation into 
the FIPS for AES, evaluation criteria will be used to review candidate 
algorithms. All of NIST's analysis results will be made publicly 
available.
    Although NIST will be performing its own analyses of the candidate 
algorithms, NIST strongly encourages public evaluation, making those 
results publicly available and submitting them to NIST. This 
information may be addressed at the Second and Third AES Candidate 
Conferences. NIST will take into account its own analysis, as well as 
all other input received, in order to make its decision regarding the 
AES selection.

Security (i.e., the effort required to cryptanalyze)

    The security provided by an algorithm is the most important factor 
in the evaluation.
    Algorithms will be judged on the following factors:
    i. Actual security of the algorithm compared to other submitted 
algorithms (at the same key and block size).
    ii. The extent to which the algorithm output is indistinguishable 
from a random permutation on the input block.
    iii. soundness of the mathematical basis for the algorithm's 
security.
    iv. Other security factors raised by the public during the 
evaluation process, including any attacks which demonstrate that the 
actual security of the algorithm is less than the strength claimed by 
the submitter.

[[Page 48056]]

    Claimed attacks will be evaluated for practicality.

Cost

    i. Licensing requirements: NIST intends that when the AES is 
issued, the algorithm(s) specified in the AES shall be available on a 
worldwide, non-exclusive, royalty-free basis.
    ii. Computational efficiency: The evaluation of computational 
efficiency will be applicable to both hardware and software 
implementations. Round 1 analysis by NIST will focus primarily on 
software implementations and specifically on one key-block size 
combination (128-128); more attention will be paid to hardware 
implementations and other supported key-block size combinations 
(particularly those required in the ``Minimum Acceptability 
Requirements'' section) during Round 2 analysis.
    Computational efficiency essentially refers to the speed of the 
algorithm. NIST's analysis of computational efficiency will be made 
using each submission's mathematically optimized implementations on the 
platform specified under ``Round 1 Technical Evaluation'' below. Public 
comments on each algorithm's efficiency (particularly for various 
platforms and applications) will also be taken into consideration by 
NIST.
    iii. Memory requirements: The memory required to implement a 
candidate algorithm--for both hardware and software implementations of 
the algorithm--will also be considered during the evaluation process. 
Round 1 analysis by NIST will focus primarily on software 
implementations; more attention will be paid to hardware 
implementations during Round 2.
    Memory requirements will include such factors as gate counts for 
hardware implementations, and code size and RAM requirements for 
software implementations.
    Testing will be performed by NIST using the mathematically 
optimized implementations provided in the submission package. Memory 
requirement estimates (for different platforms and environments) that 
are included in the submission package will also be taken into 
consideration by NIST. Input from public evaluations of each 
algorithm's memory requirements (particularly for various platforms and 
applications) will also be taken into consideration by NIST.

Algorithm and Implementation Characteristics

    i. Flexibility: Candidate algorithms with greater flexibility will 
meet the needs of more users than less flexible ones, and therefore, 
inter alia, are preferable. However, some extremes of functionality are 
of little practical application (e.g., extremely short key lengths)--
for those cases, preference will not be given.
    Some examples of ``flexibility'' may include (but are not limited 
to) the following:
    a. The algorithm can accommodate additional key- and block-sizes 
(e.g., 64-bit block sizes, key sizes other than those specified in the 
Minimum Acceptability Requirements section, [e.g., keys between 128 and 
256 that are multiples of 32 bits, etc.]).
    b. The algorithm can be implemented securely and efficiently in a 
wide variety of platforms and applications (e.g., 8-bit processors, ATM 
networks, voice & satellite communications, HDTV, B-ISDN, etc.).
    c. The algorithm can be implemented as a stream cipher, Message 
Authentication Code (MAC) generator, pseudo-random number generator, 
hashing algorithm, etc.
    ii. Hardware and software suitability: A candidate algorithm shall 
not be restrictive in the sense that it can only be implemented in 
hardware. If one can also implement the algorithm efficiency in 
firmware, then this will be an advantage in the area of flexibility.
    iii. Simplicity: A candidate algorithm shall be judged according to 
relative simplicity of design.

5. Initial Planning for the First AES Candidate Conference

    An open public conference is being planned for the summer of 1998, 
at which the submitter of each complete and proper nomination package 
is invited to publicly discuss and explain their candidate algorithm.
    Written portions of all submitted candidates will be made available 
at the Conference, including those not deemed ``complete and proper.'' 
Submitters of complete and proper submissions will be invited to speak 
to discuss their submission and answer questions.
    As details and registration procedures are finalized, they will be 
posted to <http://csrc.nist.gov/encryption/>.

6. Plans for Candidate Evaluation Process

    This section provides an overview of the envisioned AES candidate 
review process, including NIST's plans for technical analysis of 
submissions.

6.A  Overview

    Following the close of the call for candidate algorithm submission 
packages, NIST will review them to determine which are ``complete and 
proper,'' as described elsewhere in this notice. NIST then intends to 
make all submissions publicly available (consistent with U.S. export 
regulations) and invite public comments on the ``complete and proper'' 
submissions. To help better inform the public, the First AES Candidate 
Conference will be held at the start of the public comment process to 
allow submitters to publicly explain and answer questions regarding 
their submissions. NIST intends to publish a separate Federal Register 
notice in the future requesting public comments on the candidate 
algorithms in the Round 1 evaluation to be used in narrowing of the 
candidate pool for more careful study and analysis in Round 2.
    During the Round 1 public review, NIST intends to technically 
evaluate the candidate algorithm as outlined in the ``Round 1 Technical 
Evaluation'' section below. Note that NIST does not intend to conduct 
its own cryptanalysis, but, rather it will review the public 
evaluations of the candidate algorithms' cryptographic strengths and 
weaknesses, and NIST will use these in determining if an algorithm 
meets the objectives of the AES. Because of limited resources, and also 
to avoid moving evaluation targets (i.e., modifying the submitted 
algorithms undergoing public review), NIST will not accept 
modifications to the submitted algorithm during Round 1.
    For informational and planning purposes, near the end of the Round 
1 public evaluation process, NIST intends to hold the Second AES 
Candidate Conference (approximately six months after the first 
conference; exact date to be scheduled.) Its purpose will be to 
publicly discuss the AEA candidate algorithms by NIST and others, and 
provide NIST with advice for narrowing the field of algorithms to be 
considered for the AEA.
    NIST thereafter intends to narrow the field of candidates to no 
more than five candidate algorithms based upon its own analysis, public 
comment, and all other available information. It is envisioned that 
this narrowing will be done primarily on security, efficiency, and 
intellectual property considerations.
    Before the start of Round 2 evaluation, submitters have the option 
of providing updated mathematically optimized implementations for use 
during the second phase of evaluation (for those algorithms remaining 
in the Round 2 evaluation). During the course of Round 1 evaluations it 
is conceivable that some small deficiencies may be identified in even 
some of the most promising

[[Page 48057]]

candidates. Therefore, for the Round 2 evaluations, small modifications 
to the submitted algorithms will be permitted for their security or 
efficiency purposes. Submitters may submit minor changes (no 
substantial redesigns) along with a supporting explanation/
justification (see below) which must be received by NIST prior to the 
beginning of Round 2. (Submitters will be notified by NIST of the exact 
deadline.) If this option is exercised, new reference and 
mathematically optimized implementations and written descriptions must 
also be provided by the start of Round 2. This will allow public review 
of the modified algorithms during the entire course of the second 
evaluation.

    Note: All proposed changes for Round 2 must be proposed by the 
submitter; no proposed changes (to the algorithm or implementations) 
will be accepted from a third party.

    After the narrowed list of candidate algorithms is officially 
announced, NIST intends that a six to nine month public review period 
will follow (the Round 2 evaluation). During the public review, NIST 
intends to technically evaluate the candidate algorithms as outlined in 
the two sections below. Near the end of the public review period, NIST 
intends to hold the Third AES Candidate Conference. (The exact date is 
to be scheduled.)
    NIST then will select the algorithm(s) for inclusion in the AES, 
which will be incorporated into a draft FIPS, which NIST intends to 
announce in the Federal Register for comment.
    Note that this schedule for the AES development is somewhat 
tentative, depending in part upon the type, quantity, and quality of 
submissions. Specific conference dates and public comment periods will 
be announced at appropriate times in the future. Note also that as a 
result of comments received on the draft evaluation criteria and 
submission requirements, NIST has further extended the length of time 
for algorithm submissions and each of the ensuing planned public 
comment periods.

6.B  Round 1 Technical Evaluation

    NIST will invite public comments on all complete and proper 
submissions. NIST's Round 1 analysis are intended, at a minimum, to be 
performed as follows:
    i. Key-Block Size Combinations: Round 1 testing by NIST will be 
performed on the 128-bit key and 128-bit block size combination. (The 
public, however, is welcome to also focus on other key- and block-size 
combinations.) Testing of other key-block sizes may be accomplished if 
time and resources permit.
    ii. Correctness check: The Known Answer Test and Monte Carlo Test 
values included with the submission will be used to test the 
correctness of the reference and mathematically optimized 
implementations, once they are compiled. (It is more likely that NIST 
will perform this check of the reference code--and possibly the 
optimized code as well--even before accepting the submission package as 
``complete and proper.'')
    iii. Efficiency testing: Using the submitted mathematically 
optimized implementations, NIST intends to perform various 
computational efficiency tests for the 128-128 key-block combination, 
including the calculation of the time required to perform:

--Algorithm setup,
--Key setup,
--Key change, and
--Encryption and decryption.

    NIST may perform efficiency testing on other platforms.
    iv. Other testing: Other features of the candidate algorithms may 
be examined by NIST.

Platform and Compilers

    The above tests will be performed by NIST with the following tools, 
at a minimum. Due to limited resources, NIST has limited its own 
efficiency analysis to a single, common platform; however, NIST invites 
the public to conduct similar tests and compare results on additional 
platforms (e.g., RISC processors, 8-bit processors, Digital Signal 
Processors, dedicated CMOS, etc.).
    i. NIST Analysis Platform: IBM-compatible PC, with an Intel Pentium 
Pro Processor, 200MHz clock speed, 64MB RAM, running Windows95.
    ii. Compiler (Note that the selection of these two compilers is for 
use by NIST in the Rounds 1 and 2, and does not constitute a direct or 
implied endorsement by NIST.):
    (a) For the reference implementation, NIST intends to use the ANSI 
C compiler in the Borland C++ Development Suite 5.0.
    (b) For the mathematically optimized implementations, NIST intends 
to use the following compilers:
    (1) ANSI C implementation: ANSI C compiler found in the Borland C++ 
Development Suite 5.0, and
    (2) Java implementation: NIST intends to use the bytecode compiler 
and virtual machine provided in Javasoft's Java Development Kit (JDK) 
1.1.

    Note: any changes to the intended platform/compiler will be 
noted on <http://csrc.nist.gov/encryption/aes>.

6.C  Round 2 Technical Evaluation

    At the end of the Round 1 Technical evaluation and the Second AES 
Candidate Conference, NIST intends to narrow the field of candidate 
algorithms to five or fewer, in order to focus the remaining efforts of 
both NIST and the public. Once again, NIST intends to perform its own 
analysis of the submissions, and make that information publicly 
available. NIST's Round 2 analysis will, at a minimum, be performed as 
follows. Note: the same platform and compilers from Round 1 will be 
used for the Round 2.
    i. Key-Block Size Combinations: Round 2 testing by NIST will be 
performed on the minimum key-block combinations specified in the 
Minimum Acceptability Requirements (beyond the 128-128 key-block 
combination that was evaluated in Round 1). Note: If the submitter 
chose to submit updated mathematically optimized implementations prior 
to the beginning of Round 2, then some of the tests performed in Round 
1 for the 128-128 combination may be performed again using the new 
mathematically optimized implementations. This will be done to obtain 
updated measurements.
    ii. Efficiency testing: Using the submitted mathematically 
optimized implementations, NIST intends to perform various 
computational efficiency tests for the minimum key-block combinations 
specified in the Minimum Acceptability Requirements, including the 
calculation of the time required to perform:

--Algorithm setup,
--Key setup,
--Key change, and
--Encryption and decryption.

    NIST will welcome comments regarding the efficiency of the 
candidate algorithms when implemented in hardware. NIST may pursue 
having the remaining algorithms specified using a Hardware Description 
Language, to compare the estimated hardware efficiency of the candidate 
algorithms.
    NIST may perform efficiency testing using additional platforms. 
Once again, NIST welcomes public input regarding efficiency testing on 
additional platforms.
    iii. Other testing: Other features of the candidate algorithms may 
be examined by NIST. If appropriate, analyses from the Second AES 
Candidate Conference and the public evaluation during Round 1 may 
warrant the testing of specific features.

[[Page 48058]]

7. Miscellaneous

    This section is intended to address some of the questions/comments 
raised in the review of the draft evaluation criteria.
    When evaluating algorithms, NIST will make every effort to obtain 
public input and will encourage review of the candidate algorithms by 
outside organizations; however, the final decision as to which 
algorithms(s) will be proposed to the Secretary of Commerce for 
inclusion in the AES is the responsibility of NIST.
    NIST intends to develop a validation program for AES conformance 
testing, with the goal of having it operational concurrently with the 
effective date of the AES.
    NIST does NOT have a fixed timeable for completion of the AES.
    NIST is not specifically seeking a stream cipher algorithm, since 
any block cipher algorithm can be operated in a stream cipher mode.
    NIST does not intend to select a wholly distinct algorithm for each 
of the minimum required key-block combinations. It is strongly 
recommended that no submission be so constructed.
    NIST does not wish to target a specific application or platform for 
implementing the AES, as the evaluation of candidate algorithms takes 
place. However, one factor that is being taken into consideration for 
each candidate algorithm is its flexibility--the ability to implement 
the algorithm securely and efficiently in a wide variety of platforms 
and applications (see ``Algorithm and Implementation Characteristics'' 
under ``Evaluation Criteria'' section).
    NIST does not intend to select a ``backup'' AES algorithm. Rather, 
should the circumstances arise (e.g., discovery of a significant 
security flaw) which could not be satisfactorily addressed by modifying 
the AES, NIST would likely look to the other AES candidate finalists. 
Additionally, if a significant period of time has elapsed since the AES 
selection, it would also make sense to examine other algorithms which 
may have been developed in the intervening period.
    Exportability decisions regarding submissions and, eventually, 
products implementing AES will be made by the appropriate government 
regulatory authorities. NIST is a non-regulatory agency of the U.S. 
Department of Commerce.
    NIST does not intend to offer financial incentives (e.g., contests) 
for cryptanalysis of AES candidates.
    Should no appropriate algorithms be submitted in response to this 
call, NIST expressly reserves the right to cease this process and 
examine other possible courses of action.
    Submitters are strongly encouraged to submit only one algorithm 
each (presumably the one in which the submitter has the greatest 
confidence). Submission of similar, yet distinct, algorithms may delay 
the public evaluation process and may well raise public questions as to 
the submitter's level of confidence in his/her candidates.
    For conference and resource allocation planning purposes, it would 
be appreciated if those planning to submit candidates could notify the 
individuals listed in the ``For Further Information'' section as soon 
as possible.

Appreciation

    NIST extends its appreciation to all submitters and those providing 
public comments during the AES development process.

    Dated: September 8, 1997.
Elaine Bunten-Mines,
Director, Program Office.
[FR Doc. 97-24214 Filed 9-11-97; 8:45 am]
BILLING CODE 3510-CN-M


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