draft-ietf-lamps-crmf-update-algs-07.txt   rfc9045.txt 
Network Working Group R. Housley Internet Engineering Task Force (IETF) R. Housley
Internet-Draft Vigil Security Request for Comments: 9045 Vigil Security
Updates: 4211 (if approved) 8 April 2021 Updates: 4211 June 2021
Intended status: Standards Track Category: Standards Track
Expires: 10 October 2021 ISSN: 2070-1721
Algorithm Requirements Update to the Internet X.509 Public Key Algorithm Requirements Update to the Internet X.509 Public Key
Infrastructure Certificate Request Message Format (CRMF) Infrastructure Certificate Request Message Format (CRMF)
draft-ietf-lamps-crmf-update-algs-07
Abstract Abstract
This document updates the cryptographic algorithm requirements for This document updates the cryptographic algorithm requirements for
the Password-Based Message Authentication Code in the Internet X.509 the Password-Based Message Authentication Code in the Internet X.509
Public Key Infrastructure Certificate Request Message Format (CRMF) Public Key Infrastructure Certificate Request Message Format (CRMF)
specified in RFC 4211. specified in RFC 4211.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 10 October 2021. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9045.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents
license-info) in effect on the date of publication of this document. (https://trustee.ietf.org/license-info) in effect on the date of
Please review these documents carefully, as they describe your rights publication of this document. Please review these documents
and restrictions with respect to this document. Code Components carefully, as they describe your rights and restrictions with respect
extracted from this document must include Simplified BSD License text to this document. Code Components extracted from this document must
as described in Section 4.e of the Trust Legal Provisions and are include Simplified BSD License text as described in Section 4.e of
provided without warranty as described in the Simplified BSD License. the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
This document may contain material from IETF Documents or IETF This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this 10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology
3. Signature Key POP . . . . . . . . . . . . . . . . . . . . . . 3 3. Signature Key POP
4. Password-Based Message Authentication Code . . . . . . . . . 3 4. Password-Based Message Authentication Code
4.1. Introduction Paragraph . . . . . . . . . . . . . . . . . 3 4.1. Introduction Paragraph
4.2. One-Way Function . . . . . . . . . . . . . . . . . . . . 4 4.2. One-Way Function
4.3. Iteration Count . . . . . . . . . . . . . . . . . . . . . 4 4.3. Iteration Count
4.4. MAC Algorithm . . . . . . . . . . . . . . . . . . . . . . 5 4.4. MAC Algorithm
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 7. References
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References
8.1. Normative References . . . . . . . . . . . . . . . . . . 7 7.2. Informative References
8.2. Informative References . . . . . . . . . . . . . . . . . 8 Acknowledgements
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9 Author's Address
1. Introduction 1. Introduction
This document updates the cryptographic algorithm requirements for This document updates the cryptographic algorithm requirements for
the Password-Based Message Authentication Code (MAC) in the Internet the Password-Based Message Authentication Code (MAC) in the Internet
X.509 Public Key Infrastructure Certificate Request Message Format X.509 Public Key Infrastructure Certificate Request Message Format
(CRMF) [RFC4211]. The algorithms specified in [RFC4211] were (CRMF) [RFC4211]. The algorithms specified in [RFC4211] were
appropriate in 2005; however, these algorithms are no longer appropriate in 2005; however, these algorithms are no longer
considered the best choices: considered the best choices:
* HMAC-SHA1 [HMAC][SHS] is not broken yet, but there are much * HMAC-SHA1 [HMAC] [SHS] is not broken yet, but there are much
stronger alternatives [RFC6194]. stronger alternatives [RFC6194].
* DES-MAC [PKCS11] provides 56 bits of security, which is no longer * DES-MAC [PKCS11] provides 56 bits of security, which is no longer
considered secure [WITHDRAW]. considered secure [WITHDRAW].
* Triple-DES-MAC [PKCS11] provides 112 bits of security, which is * Triple-DES-MAC [PKCS11] provides 112 bits of security, which is
now deprecated [TRANSIT]. now deprecated [TRANSIT].
This update specifies algorithms that are more appropriate today. This update specifies algorithms that are more appropriate today.
skipping to change at page 3, line 19 skipping to change at line 109
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Signature Key POP 3. Signature Key POP
Section 4.1 of [RFC4211] specifies the Proof-of-Possession (POP) Section 4.1 of [RFC4211] specifies the proof-of-possession (POP)
processing. This section is updated to explicitly allow the use of processing. This section is updated to explicitly allow the use of
the PBMAC1 algorithm presented in Section 7.1 of [RFC8018]. the PBMAC1 algorithm presented in Section 7.1 of [RFC8018].
OLD: OLD:
algId identifies the algorithm used to compute the MAC value. All | algId identifies the algorithm used to compute the MAC value. All
implementations MUST support id-PasswordBasedMAC. The details on | implementations MUST support id-PasswordBasedMAC. The details on
this algorithm are presented in section 4.4 | this algorithm are presented in section 4.4.
NEW: NEW:
algId identifies the algorithm used to compute the MAC value. All | algId identifies the algorithm used to compute the MAC value. All
implementations MUST support id-PasswordBasedMAC as presented in | implementations MUST support id-PasswordBasedMAC as presented in
Section 4.4 of [RFC4211]. Implementations MAY also support PBMAC1 | Section 4.4 of [RFC4211]. Implementations MAY also support PBMAC1
as presented in Section 7.1 of [RFC8018]. | as presented in Section 7.1 of [RFC8018].
4. Password-Based Message Authentication Code 4. Password-Based Message Authentication Code
Section 4.4 of [RFC4211] specifies a Password-Based MAC that relies Section 4.4 of [RFC4211] specifies a Password-Based MAC that relies
on a one-way function to compute a symmetric key from the password on a one-way function to compute a symmetric key from the password
and a MAC algorithm. This section specifies algorithm requirements and a MAC algorithm. This section specifies algorithm requirements
for the one-way function and the MAC algorithm. for the one-way function and the MAC algorithm.
4.1. Introduction Paragraph 4.1. Introduction Paragraph
Add guidance about limiting the use of the password. Add guidance about limiting the use of the password as follows:
OLD: OLD:
This MAC algorithm was designed to take a shared secret (a | This MAC algorithm was designed to take a shared secret (a
password) and use it to compute a check value over a piece of | password) and use it to compute a check value over a piece of
information. The assumption is that, without the password, the | information. The assumption is that, without the password, the
correct check value cannot be computed. The algorithm computes | correct check value cannot be computed. The algorithm computes
the one-way function multiple times in order to slow down any | the one-way function multiple times in order to slow down any
dictionary attacks against the password value. | dictionary attacks against the password value.
NEW: NEW:
This MAC algorithm was designed to take a shared secret (a | This MAC algorithm was designed to take a shared secret (a
password) and use it to compute a check value over a piece of | password) and use it to compute a check value over a piece of
information. The assumption is that, without the password, the | information. The assumption is that, without the password, the
correct check value cannot be computed. The algorithm computes | correct check value cannot be computed. The algorithm computes
the one-way function multiple times in order to slow down any | the one-way function multiple times in order to slow down any
dictionary attacks against the password value. The password used | dictionary attacks against the password value. The password used
to compute this MAC SHOULD NOT be used for any other purpose. | to compute this MAC SHOULD NOT be used for any other purpose.
4.2. One-Way Function 4.2. One-Way Function
Change the paragraph describing the "owf" as follows: Change the paragraph describing the "owf" as follows:
OLD: OLD:
owf identifies the algorithm and associated parameters used to | owf identifies the algorithm and associated parameters used to
compute the key used in the MAC process. All implementations MUST | compute the key used in the MAC process. All implementations MUST
support SHA-1. | support SHA-1.
NEW: NEW:
owf identifies the algorithm and associated parameters used to | owf identifies the algorithm and associated parameters used to
compute the key used in the MAC process. All implementations MUST | compute the key used in the MAC process. All implementations MUST
support SHA-256 [SHS]. | support SHA-256 [SHS].
4.3. Iteration Count 4.3. Iteration Count
Update the guidance on appropriate iteration count values. Update the guidance on appropriate iteration count values as follows:
OLD: OLD:
iterationCount identifies the number of times the hash is applied | iterationCount identifies the number of times the hash is applied
during the key computation process. The iterationCount MUST be a | during the key computation process. The iterationCount MUST be a
minimum of 100. Many people suggest using values as high as 1000 | minimum of 100. Many people suggest using values as high as 1000
iterations as the minimum value. The trade off here is between | iterations as the minimum value. The trade off here is between
protection of the password from attacks and the time spent by the | protection of the password from attacks and the time spent by the
server processing all of the different iterations in deriving | server processing all of the different iterations in deriving
passwords. Hashing is generally considered a cheap operation but | passwords. Hashing is generally considered a cheap operation but
this may not be true with all hash functions in the future. | this may not be true with all hash functions in the future.
NEW: NEW:
iterationCount identifies the number of times the hash is applied | iterationCount identifies the number of times the hash is applied
during the key computation process. The iterationCount MUST be a | during the key computation process. The iterationCount MUST be a
minimum of 100; however, the iterationCount SHOULD be as large as | minimum of 100; however, the iterationCount SHOULD be as large as
server performance will allow, typically at least 10,000 [DIGALM]. | server performance will allow, typically at least 10,000 [DIGALM].
There is a trade off between protection of the password from | There is a trade-off between protection of the password from
attacks and the time spent by the server processing the | attacks and the time spent by the server processing the
iterations. As part of that tradeoff, an iteration count smaller | iterations. As part of that trade-off, an iteration count smaller
than 10,000 can be used when automated generation produces shared | than 10,000 can be used when automated generation produces shared
secrets with high entropy. | secrets with high entropy.
4.4. MAC Algorithm 4.4. MAC Algorithm
Change the paragraph describing the "mac" as follows: Change the paragraph describing the "mac" as follows:
OLD: OLD:
mac identifies the algorithm and associated parameters of the MAC | mac identifies the algorithm and associated parameters of the MAC
function to be used. All implementations MUST support HMAC-SHA1 | function to be used. All implementations MUST support HMAC-SHA1
[HMAC]. All implementations SHOULD support DES-MAC and Triple- | [HMAC]. All implementations SHOULD support DES-MAC and Triple-
DES-MAC [PKCS11]. | DES-MAC [PKCS11].
NEW: NEW:
mac identifies the algorithm and associated parameters of the MAC | mac identifies the algorithm and associated parameters of the MAC
function to be used. All implementations MUST support HMAC-SHA256 | function to be used. All implementations MUST support HMAC-SHA256
[HMAC]. All implementations SHOULD support AES-GMAC [AES][GMAC] | [HMAC]. All implementations SHOULD support AES-GMAC [AES] [GMAC]
with a 128-bit key. | with a 128-bit key.
For convenience, the identifiers for these two algorithms are For convenience, the identifiers for these two algorithms are
repeated here. repeated here.
The ASN.1 algorithm identifier for HMAC-SHA256 is defined in The ASN.1 algorithm identifier for HMAC-SHA256 is defined in
[RFC4231]: [RFC4231]:
id-hmacWithSHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-hmacWithSHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) digestAlgorithm(2) 9 } us(840) rsadsi(113549) digestAlgorithm(2) 9 }
When this object identifier is used in the ASN.1 algorithm When this object identifier is used in the ASN.1 algorithm
identifier, the parameters SHOULD be present. When present, the identifier, the parameters SHOULD be present. When present, the
parameters MUST contain a type of NULL as specified in [RFC4231]. parameters MUST contain a type of NULL as specified in [RFC4231].
The ASN.1 algorithm identifier for AES-GMAC [AES][GMAC] with a The ASN.1 algorithm identifier for AES-GMAC [AES] [GMAC] with a
128-bit key is defined in [I-D.ietf-lamps-cms-aes-gmac-alg]: 128-bit key is defined in [RFC9044]:
id-aes128-GMAC OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) id-aes128-GMAC OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3) country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) aes(1) 9 } nistAlgorithm(4) aes(1) 9 }
When this object identifier is used in the ASN.1 algorithm When this object identifier is used in the ASN.1 algorithm
identifier, the parameters MUST be present, and the parameters MUST identifier, the parameters MUST be present, and the parameters MUST
contain the GMACParameters structure as follows: contain the GMACParameters structure as follows:
GMACParameters ::= SEQUENCE { GMACParameters ::= SEQUENCE {
skipping to change at page 6, line 33 skipping to change at line 261
processed more efficiently, so that length for the nonce value is processed more efficiently, so that length for the nonce value is
RECOMMENDED. RECOMMENDED.
The GMACParameters length parameter field tells the size of the The GMACParameters length parameter field tells the size of the
message authentication code in octets. GMAC supports lengths between message authentication code in octets. GMAC supports lengths between
12 and 16 octets, inclusive. However, for use with CRMF, the maximum 12 and 16 octets, inclusive. However, for use with CRMF, the maximum
length of 16 octets MUST be used. length of 16 octets MUST be used.
5. IANA Considerations 5. IANA Considerations
This document makes no requests of the IANA. This document has no IANA actions.
6. Security Considerations 6. Security Considerations
The security of the password-based MAC relies on the number of times The security of the Password-Based MAC relies on the number of times
the hash function is applied as well as the entropy of the shared the hash function is applied as well as the entropy of the shared
secret (the password). Hardware support for hash calculation is secret (the password). Hardware support for hash calculation is
available at very low cost [PHS], which reduces the protection available at very low cost [PHS], which reduces the protection
provided by a high iterationCount value. Therefore, the entropy of provided by a high iterationCount value. Therefore, the entropy of
the password is crucial for the security of the password-based MAC the password is crucial for the security of the Password-Based MAC
function. In 2010, researchers showed that about half of the real- function. In 2010, researchers showed that about half of the real-
world passwords in a leaked corpus can be broken with less than 150 world passwords in a leaked corpus can be broken with less than 150
million trials, indicating a median entropy of only 27 bits [DMR]. million trials, indicating a median entropy of only 27 bits [DMR].
Higher entropy can be achieved by using randomly generated strings. Higher entropy can be achieved by using randomly generated strings.
For example, assuming an alphabet of 60 characters a randomly chosen For example, assuming an alphabet of 60 characters, a randomly chosen
password with 10 characters offers 59 bits of entropy, and 20 password with 10 characters offers 59 bits of entropy, and 20
characters offers 118 bits of entropy. Using a one-time password characters offers 118 bits of entropy. Using a one-time password
also increases the security of the MAC, assuming that the integrity- also increases the security of the MAC, assuming that the integrity-
protected transaction will complete before the attacker is able to protected transaction will complete before the attacker is able to
learn the password with an offline attack. learn the password with an offline attack.
Please see [RFC8018] for security considerations related to PBMAC1. Please see [RFC8018] for security considerations related to PBMAC1.
Please see [HMAC] and [SHS] for security considerations related to Please see [HMAC] and [SHS] for security considerations related to
HMAC-SHA256. HMAC-SHA256.
Please see [AES] and [GMAC] for security considerations related to Please see [AES] and [GMAC] for security considerations related to
AES-GMAC. AES-GMAC.
Cryptographic algorithms age; they become weaker with time. As new Cryptographic algorithms age; they become weaker with time. As new
cryptanalysis techniques are developed and computing capabilities cryptanalysis techniques are developed and computing capabilities
improve, the work required to break a particular cryptographic improve, the work required to break a particular cryptographic
algorithm will reduce, making an attack on the algorithm more algorithm will reduce, making an attack on the algorithm more
feasible for more attackers. While it is unknown how cryptoanalytic feasible for more attackers. While it is unknown how cryptanalytic
attacks will evolve, it is certain that they will get better. It is attacks will evolve, it is certain that they will get better. It is
unknown how much better they will become or when the advances will unknown how much better they will become or when the advances will
happen. For this reason, the algorithm requirements for CRMF are happen. For this reason, the algorithm requirements for CRMF are
updated by this specification. updated by this specification.
When a Password-Based MAC is used, implementations must protect the When a Password-Based MAC is used, implementations must protect the
password and the MAC key. Compromise of either the password or the password and the MAC key. Compromise of either the password or the
MAC key may result in the ability of an attacker to undermine MAC key may result in the ability of an attacker to undermine
authentication. authentication.
7. Acknowledgements 7. References
Many thanks to Hans Aschauer, Hendrik Brockhaus, Quynh Dang, Roman
Danyliw, Lars Eggert, Tomas Gustavsson, Jonathan Hammell, Tim
Hollebeek, Ben Kaduk, Erik Kline, Lijun Liao, Mike Ounsworth,
Francesca Palombini, Tim Polk, Ines Robles, Mike StJohns, and Sean
Turner for their careful review and improvements.
8. References
8.1. Normative References 7.1. Normative References
[AES] National Institute of Standards and Technology, "Advanced [AES] National Institute of Standards and Technology, "Advanced
encryption standard (AES)", DOI 10.6028/nist.fips.197, Encryption Standard (AES)", FIPS PUB 197,
November 2001, <https://doi.org/10.6028/nist.fips.197>. DOI 10.6028/NIST.FIPS.197, November 2001,
<https://doi.org/10.6028/NIST.FIPS.197>.
[GMAC] National Institute of Standards and Technology, [GMAC] Dworkin, M., "Recommendation for Block Cipher Modes of
"Recommendation for block cipher modes of operation: Operation: Galois/Counter Mode (GCM) and GMAC", NIST
Galois Counter Mode (GCM) and GMAC", Special Publication 800-38D, DOI 10.6028/NIST.SP.800-38D,
DOI 10.6028/nist.sp.800-38d, 2007, November 2007, <https://doi.org/10.6028/NIST.SP.800-38D>.
<https://doi.org/10.6028/nist.sp.800-38d>.
[HMAC] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [HMAC] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997, DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/rfc/rfc2104>. <https://www.rfc-editor.org/info/rfc2104>.
[I-D.ietf-lamps-cms-aes-gmac-alg]
Housley, R., "Using the AES-GMAC Algorithm with the
Cryptographic Message Syntax (CMS)", Work in Progress,
Internet-Draft, draft-ietf-lamps-cms-aes-gmac-alg-02, 30
December 2020, <http://www.ietf.org/internet-drafts/draft-
ietf-lamps-cms-aes-gmac-alg-02.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure [RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
Certificate Request Message Format (CRMF)", RFC 4211, Certificate Request Message Format (CRMF)", RFC 4211,
DOI 10.17487/RFC4211, September 2005, DOI 10.17487/RFC4211, September 2005,
<https://www.rfc-editor.org/info/rfc4211>. <https://www.rfc-editor.org/info/rfc4211>.
[RFC8018] Moriarty, K., Ed., Kaliski, B., and A. Rusch, "PKCS #5: [RFC8018] Moriarty, K., Ed., Kaliski, B., and A. Rusch, "PKCS #5:
Password-Based Cryptography Specification Version 2.1", Password-Based Cryptography Specification Version 2.1",
RFC 8018, DOI 10.17487/RFC8018, January 2017, RFC 8018, DOI 10.17487/RFC8018, January 2017,
<https://www.rfc-editor.org/info/rfc8018>. <https://www.rfc-editor.org/info/rfc8018>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9044] Housley, R., "Using the AES-GMAC Algorithm with the
Cryptographic Message Syntax (CMS)", RFC 9044,
DOI 10.17487/RFC9044, May 2021,
<https://www.rfc-editor.org/info/rfc9044>.
[SHS] National Institute of Standards and Technology, "Secure [SHS] National Institute of Standards and Technology, "Secure
Hash Standard", DOI 10.6028/nist.fips.180-4, July 2015, Hash Standard (SHS)", FIPS PUB 180-4,
<https://doi.org/10.6028/nist.fips.180-4>. DOI 10.6028/NIST.FIPS.180-4, August 2015,
<https://doi.org/10.6028/NIST.FIPS.180-4>.
[X680] ITU-T, "Information technology -- Abstract Syntax Notation [X680] ITU-T, "Information technology -- Abstract Syntax Notation
One (ASN.1): Specification of basic notation", One (ASN.1): Specification of basic notation", ITU-T
Recommendation X.680, 2015. Recommendation X.680, August 2015.
8.2. Informative References 7.2. Informative References
[DIGALM] National Institute of Standards and Technology, "Digital [DIGALM] National Institute of Standards and Technology, "Digital
identity guidelines: authentication and lifecycle Identity Guidelines: Authentication and Lifecycle
management", DOI 10.6028/nist.sp.800-63b, June 2017, Management", NIST Special Publication 800-63B,
<https://doi.org/10.6028/nist.sp.800-63b>. DOI 10.6028/NIST.SP.800-63B, June 2017,
<https://doi.org/10.6028/NIST.SP.800-63B>.
[DMR] Dell'Amico, M., Michiardi, P., and Y. Roudier, "Password [DMR] Dell'Amico, M., Michiardi, P., and Y. Roudier, "Password
Strength: An Empirical Analysis", Strength: An Empirical Analysis",
DOI 10.1109/INFCOM.2010.5461951, March 2010, DOI 10.1109/INFCOM.2010.5461951, March 2010,
<https://doi.org/10.1109/INFCOM.2010.5461951>. <https://doi.org/10.1109/INFCOM.2010.5461951>.
[PHS] Pathirana, A., Halgamuge, M., and A. Syed, "Energy [PHS] Pathirana, A., Halgamuge, M., and A. Syed, "Energy
efficient bitcoin mining to maximize the mining profit: Efficient Bitcoin Mining to Maximize the Mining Profit:
Using data from 119 bitcoin mining hardware setups", Using Data from 119 Bitcoin Mining Hardware Setups",
International Conference on Advances in Business International Conference on Advances in Business
Management and Information Technology, pp 1-14, November Management and Information Technology, pp. 1-14, November
2019. 2019.
[PKCS11] RSA Laboratories, "The Public-Key Cryptography Standards - [PKCS11] RSA Laboratories, "PKCS #11 v2.11: Cryptographic Token
PKCS #11 v2.11: Cryptographic Token Interface Standard", Interface Standard", November 2001.
June 2001.
[RFC4231] Nystrom, M., "Identifiers and Test Vectors for HMAC-SHA- [RFC4231] Nystrom, M., "Identifiers and Test Vectors for HMAC-SHA-
224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512", 224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512",
RFC 4231, DOI 10.17487/RFC4231, December 2005, RFC 4231, DOI 10.17487/RFC4231, December 2005,
<https://www.rfc-editor.org/info/rfc4231>. <https://www.rfc-editor.org/info/rfc4231>.
[RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security [RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security
Considerations for the SHA-0 and SHA-1 Message-Digest Considerations for the SHA-0 and SHA-1 Message-Digest
Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011, Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011,
<https://www.rfc-editor.org/info/rfc6194>. <https://www.rfc-editor.org/info/rfc6194>.
[TRANSIT] National Institute of Standards and Technology, [TRANSIT] National Institute of Standards and Technology,
"Transitioning the use of cryptographic algorithms and key "Transitioning the Use of Cryptographic Algorithms and Key
lengths", NIST SP 800-131Ar2, March 2019. Lengths", NIST Special Publication 800-131Ar2,
DOI 10.6028/NIST.SP.800-131Ar2, March 2019,
<https://doi.org/10.6028/NIST.SP.800-131Ar2>.
[WITHDRAW] National Institute of Standards and Technology, "NIST [WITHDRAW] National Institute of Standards and Technology, "NIST
Withdraws Outdated Data Encryption Standard", 2 June 2005. Withdraws Outdated Data Encryption Standard", June 2005,
<https://www.nist.gov/news-events/news/2005/06/nist-
withdraws-outdated-data-encryption-standard>.
Acknowledgements
Many thanks to Hans Aschauer, Hendrik Brockhaus, Quynh Dang, Roman
Danyliw, Lars Eggert, Tomas Gustavsson, Jonathan Hammell, Tim
Hollebeek, Ben Kaduk, Erik Kline, Lijun Liao, Mike Ounsworth,
Francesca Palombini, Tim Polk, Ines Robles, Mike StJohns, and Sean
Turner for their careful review and improvements.
Author's Address Author's Address
Russ Housley Russ Housley
Vigil Security, LLC Vigil Security, LLC
516 Dranesville Road 516 Dranesville Road
Herndon, VA, 20170 Herndon, VA 20170
United States of America United States of America
Email: housley@vigilsec.com Email: housley@vigilsec.com
 End of changes. 43 change blocks. 
145 lines changed or deleted 145 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/