< draft-multiformats-multihash-03.txt		draft-multiformats-multihash-04.txt >
	Network Working Group J.B. Benet		Network Working Group J.B. Benet
	Internet-Draft Protocol Labs		Internet-Draft Protocol Labs
	Intended status: Informational M.S. Sporny		Intended status: Informational M.S. Sporny
	Expires: 16 February 2022 Digital Bazaar		Expires: 20 August 2022 Digital Bazaar
	August 2021		February 2022
	The Multihash Data Format		The Multihash Data Format
	draft-multiformats-multihash-03		draft-multiformats-multihash-04
	Abstract		Abstract
	Cryptographic hash functions often have multiple output sizes and		Cryptographic hash functions often have multiple output sizes and
	encodings. This variability makes it difficult for applications to		encodings. This variability makes it difficult for applications to
	examine a series of bytes and determine which hash function produced		examine a series of bytes and determine which hash function produced
	them. Multihash is a universal data format for encoding outputs from		them. Multihash is a universal data format for encoding outputs from
	hash functions. It is useful to write applications that can		hash functions. It is useful to write applications that can
	simultaneously support different hash function outputs as well as		simultaneously support different hash function outputs as well as
	upgrade their use of hashes over time; Multihash is intended to		upgrade their use of hashes over time; Multihash is intended to
	skipping to change at page 1, line 48 ¶		skipping to change at page 1, line 48 ¶
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	Copyright Notice		Copyright Notice
	Copyright (c) 2021 IETF Trust and the persons identified as the		Copyright (c) 2022 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 (https://trustee.ietf.org/
	license-info) in effect on the date of publication of this document.		license-info) in effect on the date of publication of this document.
	Please review these documents carefully, as they describe your rights		Please review these documents carefully, as they describe your rights
	and restrictions with respect to this document.		and restrictions with respect to this document.
	Table of Contents		Table of Contents
	skipping to change at page 2, line 44 ¶		skipping to change at page 2, line 44 ¶
	B.3. SHA-512/256 . . . . . . . . . . . . . . . . . . . . . . . 6		B.3. SHA-512/256 . . . . . . . . . . . . . . . . . . . . . . . 6
	B.4. SHA-512 . . . . . . . . . . . . . . . . . . . . . . . . . 6		B.4. SHA-512 . . . . . . . . . . . . . . . . . . . . . . . . . 6
	B.5. blake2b512 . . . . . . . . . . . . . . . . . . . . . . . 7		B.5. blake2b512 . . . . . . . . . . . . . . . . . . . . . . . 7
	B.6. blake2b256 . . . . . . . . . . . . . . . . . . . . . . . 7		B.6. blake2b256 . . . . . . . . . . . . . . . . . . . . . . . 7
	B.7. blake2s256 . . . . . . . . . . . . . . . . . . . . . . . 7		B.7. blake2s256 . . . . . . . . . . . . . . . . . . . . . . . 7
	B.8. blake2s128 . . . . . . . . . . . . . . . . . . . . . . . 7		B.8. blake2s128 . . . . . . . . . . . . . . . . . . . . . . . 7
	Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 7		Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 7
	Appendix D. IANA Considerations . . . . . . . . . . . . . . . . 7		Appendix D. IANA Considerations . . . . . . . . . . . . . . . . 7
	D.1. The Multihash Identifier Registry . . . . . . . . . . . . 8		D.1. The Multihash Identifier Registry . . . . . . . . . . . . 8
	D.2. The 'mh' Digest Algorithm . . . . . . . . . . . . . . . . 25		D.2. The 'mh' Digest Algorithm . . . . . . . . . . . . . . . . 25
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25		D.3. The 'mh' Named Information Hash Algorithm . . . . . . . . 25
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
	1. Introduction		1. Introduction
	Multihash is particularly important in systems which depend on		Multihash is particularly important in systems which depend on
	cryptographically secure hash functions. Attacks may break the		cryptographically secure hash functions. Attacks may break the
	cryptographic properties of secure hash functions. These		cryptographic properties of secure hash functions. These
	cryptographic breaks are particularly painful in large tool		cryptographic breaks are particularly painful in large tool
	ecosystems, where tools may have made assumptions about hash values,		ecosystems, where tools may have made assumptions about hash values,
	such as function and digest size. Upgrading becomes a nightmare, as		such as function and digest size. Upgrading becomes a nightmare, as
	all tools which make those assumptions would have to be upgraded to		all tools which make those assumptions would have to be upgraded to
	skipping to change at page 8, line 49 ¶		skipping to change at page 8, line 49 ¶
	| keccak-224 | 0x1a | active | Unknown |		| keccak-224 | 0x1a | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| keccak-256 | 0x1b | active | Unknown |		| keccak-256 | 0x1b | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| keccak-384 | 0x1c | active | Unknown |		| keccak-384 | 0x1c | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| keccak-512 | 0x1d | active | Unknown |		| keccak-512 | 0x1d | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| blake3 | 0x1e | active | Unknown |		| blake3 | 0x1e | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| murmur3-128 | 0x22 | active | Unknown |		| sha2-384 | 0x20 | active | RFC 6234 |
			| | | | [RFC6234] |
			+------------------------------+----------+----------+--------------+
			| murmur3-x64-64 | 0x22 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| murmur3-32 | 0x23 | active | Unknown |		| murmur3-32 | 0x23 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| dbl-sha2-256 | 0x56 | active | Unknown |		| dbl-sha2-256 | 0x56 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| md4 | 0xd4 |deprecated| RFC 6150 |		| md4 | 0xd4 |deprecated| RFC 6150 |
	| | | | [RFC6150] |		| | | | [RFC6150] |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| md5 | 0xd5 |deprecated| RFC 6151 |		| md5 | 0xd5 |deprecated| RFC 6151 |
	| | | | [RFC6151] |		| | | | [RFC6151] |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| bmt | 0xd6 | active | Unknown |		| bmt | 0xd6 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| sha2-256-trunc254-padded | 0x1012 | active | RFC 6234 |		| sha2-256-trunc254-padded | 0x1012 | active | RFC 6234 |
	| | | | [RFC6234] |		| | | | [RFC6234] |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
			| sha2-224 | 0x1013 | active | RFC 6234 |
			| | | | [RFC6234] |
			+------------------------------+----------+----------+--------------+
			| sha2-512-224 | 0x1014 | active | RFC 6234 |
			| | | | [RFC6234] |
			+------------------------------+----------+----------+--------------+
			| sha2-512-256 | 0x1015 | active | RFC 6234 |
			| | | | [RFC6234] |
			+------------------------------+----------+----------+--------------+
			| murmur3-x64-128 | 0x1022 | active | Unknown |
			+------------------------------+----------+----------+--------------+
	| ripemd-128 | 0x1052 | active | Unknown |		| ripemd-128 | 0x1052 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| ripemd-160 | 0x1053 | active | Unknown |		| ripemd-160 | 0x1053 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| ripemd-256 | 0x1054 | active | Unknown |		| ripemd-256 | 0x1054 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| ripemd-320 | 0x1055 | active | Unknown |		| ripemd-320 | 0x1055 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
	| x11 | 0x1100 | active | Unknown |		| x11 | 0x1100 | active | Unknown |
	+------------------------------+----------+----------+--------------+		+------------------------------+----------+----------+--------------+
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	Digest Algorithm: mh		Digest Algorithm: mh
	Description: The multibase-serialized value of a multihash-supported		Description: The multibase-serialized value of a multihash-supported
	algorithm.		algorithm.
	References: this document		References: this document
	Status: standard		Status: standard
			D.3. The 'mh' Named Information Hash Algorithm
			This memo registers the "mh" hash algorithm in the Named Information
			Hash Algorithm (https://www.iana.org/assignments/named-information/
			named-information.xhtml#hash-alg) registry with the following values:
			ID: 49
			Hash Name String: mh
			Value Length: variable
			Reference: this document
			Status: current
	Authors' Addresses		Authors' Addresses
	Juan Benet		Juan Benet
	Protocol Labs		Protocol Labs
	548 Market Street, #51207		548 Market Street, #51207
	San Francisco, CA 94104		San Francisco, CA 94104
	United States of America		United States of America
	Phone: +1 619 957 7606		Phone: +1 619 957 7606
	Email: juan@protocol.ai		Email: juan@protocol.ai
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	7 lines changed or deleted		37 lines changed or added
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