< draft-ietf-precis-saslprepbis-00.txt		draft-ietf-precis-saslprepbis-01.txt >
	PRECIS P. Saint-Andre		PRECIS P. Saint-Andre
	Internet-Draft Cisco Systems, Inc.		Internet-Draft Cisco Systems, Inc.
	Obsoletes: 4013 (if approved) A. Melnikov		Obsoletes: 4013 (if approved) A. Melnikov
	Intended status: Standards Track Isode Ltd		Intended status: Standards Track Isode Ltd
	Expires: August 17, 2013 February 13, 2013		Expires: September 28, 2013 March 27, 2013
	Preparation and Comparison of Internationalized Strings Representing		Preparation and Comparison of Internationalized Strings Representing
	Simple User Names and Passwords		Simple User Names and Passwords
	draft-ietf-precis-saslprepbis-00		draft-ietf-precis-saslprepbis-01
	Abstract		Abstract
	This document describes how to handle Unicode strings representing		This document describes how to handle Unicode strings representing
	simple user names and passwords, primarily for purposes of		simple user names and passwords, primarily for purposes of
	comparison. This profile is intended to be used by Simple		comparison. This profile is intended to be used by Simple
	Authentication and Security Layer (SASL) mechanisms (such as PLAIN		Authentication and Security Layer (SASL) mechanisms (such as PLAIN
	and SCRAM-SHA-1), as well as other protocols that exchange simple		and SCRAM-SHA-1), as well as other protocols that exchange simple
	user names or passwords. This document obsoletes RFC 4013.		user names or passwords. This document obsoletes RFC 4013.
	skipping to change at page 1, line 37 ¶		skipping to change at page 1, line 37 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on August 17, 2013.		This Internet-Draft will expire on September 28, 2013.
	Copyright Notice		Copyright Notice
	Copyright (c) 2013 IETF Trust and the persons identified as the		Copyright (c) 2013 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		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 15 ¶		skipping to change at page 2, line 15 ¶
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 2		1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Simple User Names . . . . . . . . . . . . . . . . . . . . . . 4		2. Simple User Names . . . . . . . . . . . . . . . . . . . . . . 4
	2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 4		2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 4
	2.2. Preparation . . . . . . . . . . . . . . . . . . . . . . . 4		2.2. Preparation . . . . . . . . . . . . . . . . . . . . . . . 5
	3. Passwords . . . . . . . . . . . . . . . . . . . . . . . . . . 5		3. Passwords . . . . . . . . . . . . . . . . . . . . . . . . . . 5
	3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 5		3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 5
	3.2. Preparation . . . . . . . . . . . . . . . . . . . . . . . 5		3.2. Preparation . . . . . . . . . . . . . . . . . . . . . . . 6
	4. Migration . . . . . . . . . . . . . . . . . . . . . . . . . . 6		4. Migration . . . . . . . . . . . . . . . . . . . . . . . . . . 6
	4.1. User Names . . . . . . . . . . . . . . . . . . . . . . . 6		4.1. User Names . . . . . . . . . . . . . . . . . . . . . . . 7
	4.2. Passwords . . . . . . . . . . . . . . . . . . . . . . . . 7		4.2. Passwords . . . . . . . . . . . . . . . . . . . . . . . . 8
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 8		5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
	5.1. Password/Passphrase Strength . . . . . . . . . . . . . . 8		5.1. Password/Passphrase Strength . . . . . . . . . . . . . . 9
	5.2. Reuse of PRECIS . . . . . . . . . . . . . . . . . . . . . 8		5.2. Reuse of PRECIS . . . . . . . . . . . . . . . . . . . . . 9
	5.3. Reuse of Unicode . . . . . . . . . . . . . . . . . . . . 8		5.3. Reuse of Unicode . . . . . . . . . . . . . . . . . . . . 9
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
	6.1. Use of NameClass . . . . . . . . . . . . . . . . . . . . 9		6.1. Use of IdentifierClass . . . . . . . . . . . . . . . . . 9
	6.2. Use of FreeClass . . . . . . . . . . . . . . . . . . . . 9		6.2. Use of FreeformClass . . . . . . . . . . . . . . . . . . 10
	7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 10		7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 10
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10		8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
	8.1. Normative References . . . . . . . . . . . . . . . . . . 10		8.1. Normative References . . . . . . . . . . . . . . . . . . 10
	8.2. Informative References . . . . . . . . . . . . . . . . . 10		8.2. Informative References . . . . . . . . . . . . . . . . . 11
	Appendix A. Differences from RFC 4013 . . . . . . . . . . . . . 11		Appendix A. Differences from RFC 4013 . . . . . . . . . . . . . 12
	Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 12		Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 12
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
	1. Introduction		1. Introduction
	1.1. Overview		1.1. Overview
	User names and passwords are used pervasively in authentication and		User names and passwords are used pervasively in authentication and
	authorization on the Internet. To increase the likelihood that the		authorization on the Internet. To increase the likelihood that the
	input and comparison of user names and passwords will work in ways		input and comparison of user names and passwords will work in ways
	skipping to change at page 4, line 20 ¶		skipping to change at page 4, line 20 ¶
	that the authentication identity used in the context of such		that the authentication identity used in the context of such
	mechanisms is a "simple user name" (see Section 2 of [RFC4422] as		mechanisms is a "simple user name" (see Section 2 of [RFC4422] as
	well as [RFC4013]). However, the exact form of a simple user name in		well as [RFC4013]). However, the exact form of a simple user name in
	any particular mechanism or deployment thereof is a local matter, and		any particular mechanism or deployment thereof is a local matter, and
	a simple user name does not necessarily map to an application		a simple user name does not necessarily map to an application
	identifier such as the localpart of an email address.		identifier such as the localpart of an email address.
	For purposes of preparation and comparison of authentication		For purposes of preparation and comparison of authentication
	identities, this document specifies that a simple user name is a		identities, this document specifies that a simple user name is a
	string of Unicode code points [UNICODE], encoded using UTF-8		string of Unicode code points [UNICODE], encoded using UTF-8
	[RFC3629], and structured as an ordered sequence of "simpleparts"		[RFC3629], and structured either as an ordered sequence of
	(where the complete simple user name can consist of a single		"simpleparts" (where the complete simple user name can consist of a
	simplepart or a space-separated sequence of simpleparts).		single simplepart or a space-separated sequence of simpleparts) or as
			a simplepart@domainpart (where the domainpart is an IP literal, an
			IPv4 address, or a fully-qualified domain name).
	Therefore the syntax for a simple user name is defined as follows		Therefore the syntax for a simple user name is defined as follows
	using the Augmented Backus-Naur Form (ABNF) as specified in		using the Augmented Backus-Naur Form (ABNF) as specified in
	[RFC5234].		[RFC5234].
	simpleusername = simplepart [1*(1*SP simplepart)]		simpleusername = simplepart [1*(1*SP simplepart)]
	simplepart = 1*(namepoint)		/ simplepart '@' domainpart
			simplepart = 1*(idpoint)
	;		;
	; a "namepoint" is a UTF-8 encoded		; an "idpoint" is a UTF-8 encoded
	; Unicode code point that conforms to		; Unicode code point that conforms to
	; the "NameClass" string class defined		; the PRECIS "IdentifierClass"
	; in draft-ietf-precis-framework		;
			domainpart = IP-literal / IPv4address / ifqdn
			;
			; the "IPv4address" and "IP-literal"
			; rules are defined in RFC 3986, and
			; the first-match-wins (a.k.a. "greedy")
			; algorithm described in RFC 3986
			; applies to the matching process
			;
			; note well that reuse of the IP-literal
			; rule from RFC 3986 implies that IPv6
			; addresses are enclosed in square
			; brackets (i.e., beginning with '['
			; and ending with ']')
			;
			ifqdn = 1*1023(domainpoint)
			;
			; a "domainpoint" is a UTF-8 encoded
			; Unicode code point that conforms to
			; RFC 5890
	;		;
	Note well that all code points and blocks not explicitly allowed in		Note well that all code points and blocks not explicitly allowed in
	the PRECIS NameClass are disallowed; this includes private use		the PRECIS IdentifierClass are disallowed; this includes private use
	characters, surrogate code points, and the other code points and		characters, surrogate code points, and the other code points and
	blocks defined as "Prohibited Output" in Section 2.3 of RFC 4013.		blocks defined as "Prohibited Output" in Section 2.3 of RFC 4013.
			Note also that common constructions such as "user@example.com" are
			allowed as simple user names when using software that conforms to
			this specification, as they were under [RFC4013].
	2.2. Preparation		2.2. Preparation
	A simple user name MUST NOT be zero bytes in length. This rule is to		A simple user name MUST NOT be zero bytes in length. This rule is to
	be enforced after any normalization and mapping of code points.		be enforced after any normalization and mapping of code points.
	Each simplepart of a simple user name MUST conform to the definition		Each simplepart of a simple user name MUST conform to the definition
	of the PRECIS NameClass provided in [FRAMEWORK], where the		of the PRECIS IdentifierClass provided in [FRAMEWORK], where the
	normalization, casemapping, and directionality rules are as described		normalization, casemapping, and directionality rules are as described
	below.		below.
	1. Unicode Normalization Form C (NFC) MUST be applied to all		1. Unicode Normalization Form C (NFC) MUST be applied to all
	characters.		characters.
	2. Uppercase and titlecase characters MUST be mapped to their		2. Uppercase and titlecase characters MUST be mapped to their
	lowercase equivalents.		lowercase equivalents.
	3. Additional mappings MAY be applied, such as those defined in		3. Additional mappings MAY be applied, such as those defined in
	skipping to change at page 5, line 24 ¶		skipping to change at page 5, line 48 ¶
	With regard to directionality, the "Bidi Rule" provided in [RFC5893]		With regard to directionality, the "Bidi Rule" provided in [RFC5893]
	applies.		applies.
	3. Passwords		3. Passwords
	3.1. Definition		3.1. Definition
	For purposes of preparation and comparison of passwords, this		For purposes of preparation and comparison of passwords, this
	document specifies that a password is a string of Unicode code points		document specifies that a password is a string of Unicode code points
	[UNICODE], encoded using UTF-8 [RFC3629], and conformant to the		[UNICODE], encoded using UTF-8 [RFC3629], and conformant to the
	PRECIS FreeClass.		PRECIS FreeformClass.
	Therefore the syntax for a password is defined as follows using the		Therefore the syntax for a password is defined as follows using the
	Augmented Backus-Naur Form (ABNF) as specified in [RFC5234].		Augmented Backus-Naur Form (ABNF) as specified in [RFC5234].
	password = 1*(freepoint)		password = 1*(freepoint)
	;		;
	; a "freepoint" is a UTF-8 encoded		; a "freepoint" is a UTF-8 encoded
	; Unicode code point that conforms to		; Unicode code point that conforms to
	; the "FreeClass" string class defined		; the PRECIS "FreeformClass"
	; in draft-ietf-precis-framework
	;		;
	Note well that all code points and blocks not explicitly allowed in		Note well that all code points and blocks not explicitly allowed in
	the PRECIS FreeClass are disallowed; this includes private use		the PRECIS FreeformClass are disallowed; this includes private use
	characters, surrogate code points, and the other code points and		characters, surrogate code points, and the other code points and
	blocks defined as "Prohibited Output" in Section 2.3 of RFC 4013.		blocks defined as "Prohibited Output" in Section 2.3 of RFC 4013.
	3.2. Preparation		3.2. Preparation
	A password MUST NOT be zero bytes in length. This rule is to be		A password MUST NOT be zero bytes in length. This rule is to be
	enforced after any normalization and mapping of code points.		enforced after any normalization and mapping of code points.
	A password MUST be treated as follows, where the operations specified		A password MUST be treated as follows, where the operations specified
	MUST be completed in the order shown:		MUST be completed in the order shown:
	1. Apply Unicode Normalization Form C (NFC) to all characters.		1. Apply Unicode Normalization Form C (NFC) to all characters.
	2. Map any instances of non-ASCII space to ASCII space (U+0020).		2. Map any instances of non-ASCII space to ASCII space (U+0020).
	3. Ensure that the resulting string conforms to the definition of		3. Ensure that the resulting string conforms to the definition of
	the PRECIS FreeClass.		the PRECIS FreeformClass.
	With regard to directionality, the "Bidi Rule" (defined in [RFC5893])		With regard to directionality, the "Bidi Rule" (defined in [RFC5893])
	and similar rules are unnecessary and inapplicable to passwords,		and similar rules are unnecessary and inapplicable to passwords,
	since they can reduce the range of characters that are allowed in a		since they can reduce the range of characters that are allowed in a
	string and therefore reduce the amount of entropy that is possible in		string and therefore reduce the amount of entropy that is possible in
	a password. Furthermore, such rules are intended to minimize the		a password. Furthermore, such rules are intended to minimize the
	possibility that the same string will be displayed differently on a		possibility that the same string will be displayed differently on a
	system set for right-to-left display and a system set for left-to-		system set for right-to-left display and a system set for left-to-
	right display; however, passwords are typically not displayed at all		right display; however, passwords are typically not displayed at all
	and are rarely meant to be interoperable across different systems in		and are rarely meant to be interoperable across different systems in
	skipping to change at page 6, line 35 ¶		skipping to change at page 7, line 12 ¶
	sections describe these differences, along with their implications		sections describe these differences, along with their implications
	for migration, in more detail.		for migration, in more detail.
	4.1. User Names		4.1. User Names
	Deployments that currently use SASLprep for handling user names might		Deployments that currently use SASLprep for handling user names might
	need to scrub existing data when migrating to use of the rules		need to scrub existing data when migrating to use of the rules
	defined in this specification. In particular:		defined in this specification. In particular:
	o SASLprep specified the use of Unicode Normalization Form KC		o SASLprep specified the use of Unicode Normalization Form KC
	(NFKC), whereas this usage of the PRECIS NameClass employs Unicode		(NFKC), whereas this usage of the PRECIS IdentifierClass employs
	Normalization Form C (NFC). In practice this change is unlikely		Unicode Normalization Form C (NFC). In practice this change is
	to cause significant problems, because NFKC provides methods for		unlikely to cause significant problems, because NFKC provides
	mapping Unicode code points with compatibility equivalents to		methods for mapping Unicode code points with compatibility
	those equivalents, whereas the PRECIS NameClass entirely disallows		equivalents to those equivalents, whereas the PRECIS
	Unicode code points with compatibility equivalents (i.e., during		IdentifierClass entirely disallows Unicode code points with
	comparison NFKC is more "aggressive" about finding matches than is		compatibility equivalents (i.e., during comparison NFKC is more
	NFC). A few examples might suffice to indicate the nature of the		"aggressive" about finding matches than is NFC). A few examples
	problem: (1) U+017F LATIN SMALL LETTER LONG S is compatibility		might suffice to indicate the nature of the problem: (1) U+017F
	equivalent to U+0073 LATIN SMALL LETTER S (2) U+2163 ROMAN NUMERAL		LATIN SMALL LETTER LONG S is compatibility equivalent to U+0073
	FOUR is compatibility equivalent to U+0049 LATIN CAPITAL LETTER I		LATIN SMALL LETTER S (2) U+2163 ROMAN NUMERAL FOUR is
	and U+0056 LATIN CAPITAL LETTER V (3) U+FB01 LATIN SMALL LIGATURE		compatibility equivalent to U+0049 LATIN CAPITAL LETTER I and
	FI is compatibility equivalent to U+0066 LATIN SMALL LETTER F and		U+0056 LATIN CAPITAL LETTER V (3) U+FB01 LATIN SMALL LIGATURE FI
			is compatibility equivalent to U+0066 LATIN SMALL LETTER F and
	U+0069 LATIN SMALL LETTER I. Under SASLprep, the use of NFKC also		U+0069 LATIN SMALL LETTER I. Under SASLprep, the use of NFKC also
	handled the mapping of fullwidth and halfwidth code points to		handled the mapping of fullwidth and halfwidth code points to
	their decomposition equivalents (see [I-D.ietf-precis-mappings]).		their decomposition equivalents (see [I-D.ietf-precis-mappings]).
	Although it is expected that code points with compatibility		Although it is expected that code points with compatibility
	equivalents are rare in existing user names, for migration		equivalents are rare in existing user names, for migration
	purposes deployments might want to search their database of user		purposes deployments might want to search their database of user
	names for Unicode code points with compatibility equivalents and		names for Unicode code points with compatibility equivalents and
	map those code points to their compatibility equivalents.		map those code points to their compatibility equivalents.
	o SASLprep mapped non-ASCII spaces to ASCII space (U+0020), whereas		o SASLprep mapped non-ASCII spaces to ASCII space (U+0020), whereas
	the PRECIS NameClass entirely disallows non-ASCII spaces. The		the PRECIS IdentifierClass entirely disallows non-ASCII spaces.
	non-ASCII space characters are U+00A0 NO-BREAK SPACE, U+1680 OGHAM		The non-ASCII space characters are U+00A0 NO-BREAK SPACE, U+1680
	SPACE MARK, U+180E MONGOLIAN VOWEL SEPARATOR, U+2000 EN QUAD		OGHAM SPACE MARK, U+180E MONGOLIAN VOWEL SEPARATOR, U+2000 EN QUAD
	through U+200A HAIR SPACE, U+202F NARROW NO-BREAK SPACE, U+205F		through U+200A HAIR SPACE, U+202F NARROW NO-BREAK SPACE, U+205F
	MEDIUM MATHEMATICAL SPACE, and U+3000 IDEOGRAPHIC SPACE. For		MEDIUM MATHEMATICAL SPACE, and U+3000 IDEOGRAPHIC SPACE. For
	migration purposes, deployments might want to convert non-ASCII		migration purposes, deployments might want to convert non-ASCII
	space characters to ASCII space in simple user names.		space characters to ASCII space in simple user names.
	o SASLprep mapped the "characters commonly mapped to nothing" from		o SASLprep mapped the "characters commonly mapped to nothing" from
	Appendix B.1 of [RFC3454]) to nothing, whereas the PRECIS		Appendix B.1 of [RFC3454]) to nothing, whereas the PRECIS
	NameClass entirely disallows most of these characters, which		IdentifierClass entirely disallows most of these characters, which
	correspond to the code points from the "M" category defined under		correspond to the code points from the "M" category defined under
	Section 6.13 of [FRAMEWORK] (with the exception of U+1806		Section 6.13 of [FRAMEWORK] (with the exception of U+1806
	MONGOLIAN TODO SOFT HYPHEN, which was "commonly mapped to nothing"		MONGOLIAN TODO SOFT HYPHEN, which was "commonly mapped to nothing"
	in Unicode 3.2 but at the time of this writing does not have a		in Unicode 3.2 but at the time of this writing does not have a
	derived property of Default_Ignorable_Code_Point in Unicode 6.1).		derived property of Default_Ignorable_Code_Point in Unicode 6.1).
	For migration purposes, deployments might want to remove code		For migration purposes, deployments might want to remove code
	points contained in the PRECIS "M" category from simple user		points contained in the PRECIS "M" category from simple user
	names.		names.
	o SASLprep allowed uppercase and titlecase characters, whereas this		o SASLprep allowed uppercase and titlecase characters, whereas this
	usage of the PRECIS NameClass maps uppercase and titlecase		usage of the PRECIS IdentifierClass maps uppercase and titlecase
	characters to their lowercase equivalents. For migration		characters to their lowercase equivalents. For migration
	purposes, deployments can either convert uppercase and titlecase		purposes, deployments can either convert uppercase and titlecase
	characters to their lowercase equivalents in simple user names		characters to their lowercase equivalents in simple user names
	(thus losing the case information) or preserve uppercase and		(thus losing the case information) or preserve uppercase and
	titlecase characters and ignore the case difference when comparing		titlecase characters and ignore the case difference when comparing
	simple user names.		simple user names.
	4.2. Passwords		4.2. Passwords
	Depending on local service policy, migration from RFC 4013 to this		Depending on local service policy, migration from RFC 4013 to this
	specification might not involve any scrubbing of data (since		specification might not involve any scrubbing of data (since
	passwords might not be stored in the clear anyway); however, service		passwords might not be stored in the clear anyway); however, service
	providers need to be aware of possible issues that might arise during		providers need to be aware of possible issues that might arise during
	migration. In particular:		migration. In particular:
	o SASLprep specified the use of Unicode Normalization Form KC		o SASLprep specified the use of Unicode Normalization Form KC
	(NFKC), whereas this usage of the PRECIS FreeClass employs Unicode		(NFKC), whereas this usage of the PRECIS FreeformClass employs
	Normalization Form C (NFC). Because NFKC is more aggressive about		Unicode Normalization Form C (NFC). Because NFKC is more
	finding matches than NFC, in practice this change is unlikely to		aggressive about finding matches than NFC, in practice this change
	cause significant problems and indeed has the security benefit of		is unlikely to cause significant problems and indeed has the
	probably resulting in fewer false positives when comparing		security benefit of probably resulting in fewer false positives
	passwords. A few examples might suffice to indicate the nature of		when comparing passwords. A few examples might suffice to
	the problem: (1) U+017F LATIN SMALL LETTER LONG S is compatibility		indicate the nature of the problem: (1) U+017F LATIN SMALL LETTER
	equivalent to U+0073 LATIN SMALL LETTER S (2) U+2163 ROMAN NUMERAL		LONG S is compatibility equivalent to U+0073 LATIN SMALL LETTER S
	FOUR is compatibility equivalent to U+0049 LATIN CAPITAL LETTER I		(2) U+2163 ROMAN NUMERAL FOUR is compatibility equivalent to
	and U+0056 LATIN CAPITAL LETTER V (3) U+FB01 LATIN SMALL LIGATURE		U+0049 LATIN CAPITAL LETTER I and U+0056 LATIN CAPITAL LETTER V
	FI is compatibility equivalent to U+0066 LATIN SMALL LETTER F and		(3) U+FB01 LATIN SMALL LIGATURE FI is compatibility equivalent to
	U+0069 LATIN SMALL LETTER I. Under SASLprep, the use of NFKC also		U+0066 LATIN SMALL LETTER F and U+0069 LATIN SMALL LETTER I.
	handled the mapping of fullwidth and halfwidth code points to		Under SASLprep, the use of NFKC also handled the mapping of
	their decomposition equivalents (see [I-D.ietf-precis-mappings]).		fullwidth and halfwidth code points to their decomposition
	Although it is expected that code points with compatibility		equivalents (see [I-D.ietf-precis-mappings]). Although it is
	equivalents are rare in existing passwords, some passwords that		expected that code points with compatibility equivalents are rare
	matched when SASLprep was used might no longer work when the rules		in existing passwords, some passwords that matched when SASLprep
	in this specification are applied.		was used might no longer work when the rules in this specification
			are applied.
	o SASLprep mapped the "characters commonly mapped to nothing" from		o SASLprep mapped the "characters commonly mapped to nothing" from
	Appendix B.1 of [RFC3454]) to nothing, whereas the PRECIS		Appendix B.1 of [RFC3454]) to nothing, whereas the PRECIS
	FreeClass entirely disallows such characters, which correspond to		FreeformClass entirely disallows such characters, which correspond
	the code points from the "M" category defined under Section 6.13		to the code points from the "M" category defined under
	of [FRAMEWORK] (with the exception of U+1806 MONGOLIAN TODO SOFT		Section 6.13 of [FRAMEWORK] (with the exception of U+1806
	HYPHEN, which was commonly mapped to nothing in Unicode 3.2 but at		MONGOLIAN TODO SOFT HYPHEN, which was commonly mapped to nothing
	the time of this writing is allowed by Unicode 6.1). In practice,		in Unicode 3.2 but at the time of this writing is allowed by
	this change will probably have no effect on comparison, but user-		Unicode 6.1). In practice, this change will probably have no
	oriented software might reject such code points instead of		effect on comparison, but user-oriented software might reject such
	ignoring them during password preparation.		code points instead of ignoring them during password preparation.
	5. Security Considerations		5. Security Considerations
	5.1. Password/Passphrase Strength		5.1. Password/Passphrase Strength
	The ability to include a wide range of characters in passwords and		The ability to include a wide range of characters in passwords and
	passphrases can increase the potential for creating a strong password		passphrases can increase the potential for creating a strong password
	with high entropy. However, in practice, the ability to include such		with high entropy. However, in practice, the ability to include such
	characters ought to be weighed against the possible need to reproduce		characters ought to be weighed against the possible need to reproduce
	them on various devices using various input methods.		them on various devices using various input methods.
	5.2. Reuse of PRECIS		5.2. Reuse of PRECIS
	The security considerations described in [FRAMEWORK] apply to the		The security considerations described in [FRAMEWORK] apply to the
	"NameClass" and "FreeClass" base string classes used in this document		"IdentifierClass" and "FreeformClass" base string classes used in
	for simple user names and passwords, respectively.		this document for simple user names and passwords, respectively.
	5.3. Reuse of Unicode		5.3. Reuse of Unicode
	The security considerations described in [UTR39] apply to the use of		The security considerations described in [UTR39] apply to the use of
	Unicode characters in user names and passwords.		Unicode characters in user names and passwords.
	6. IANA Considerations		6. IANA Considerations
	6.1. Use of NameClass
			6.1. Use of IdentifierClass
	The IANA shall add an entry to the PRECIS Usage Registry for reuse of		The IANA shall add an entry to the PRECIS Usage Registry for reuse of
	the PRECIS NameClass in SASL, as follows:		the PRECIS IdentifierClass in SASL, as follows:
	Applicability: Usernames in SASL and Kerberos.		Applicability: Usernames in SASL and Kerberos.
	Base Class: NameClass.		Base Class: IdentifierClass.
	Subclass: No.		Subclass: No.
	Replaces: The SASLprep profile of Stringprep.		Replaces: The SASLprep profile of Stringprep.
	Normalization: NFC.		Normalization: NFC.
	Casemapping: Map uppercase and titlecase characters to lowercase.		Casemapping: Map uppercase and titlecase characters to lowercase.
	Additional Mappings: None.		Additional Mappings: None.
	Directionality: The "Bidi Rule" defined in RFC 5893 applies.		Directionality: The "Bidi Rule" defined in RFC 5893 applies.
	Specification: RFC XXXX. [Note to RFC Editor: please change XXXX to		Specification: RFC XXXX. [Note to RFC Editor: please change XXXX to
	the number issued for this specification.]		the number issued for this specification.]
	6.2. Use of FreeClass		6.2. Use of FreeformClass
	The IANA shall add an entry to the PRECIS Usage Registry for reuse of		The IANA shall add an entry to the PRECIS Usage Registry for reuse of
	the PRECIS FreeClass in SASL, as follows:		the PRECIS FreeformClass in SASL, as follows:
	Applicability: Passwords in SASL and Kerberos.		Applicability: Passwords in SASL and Kerberos.
	Base Class: FreeClass		Base Class: FreeformClass
	Subclass: No.		Subclass: No.
	Replaces: The SASLprep profile of Stringprep.		Replaces: The SASLprep profile of Stringprep.
	Normalization: NFC.		Normalization: NFC.
	Casemapping: None.		Casemapping: None.
	Additional Mappings: Map non-ASCII space characters to ASCII space.		Additional Mappings: Map non-ASCII space characters to ASCII space.
	skipping to change at page 10, line 22 ¶		skipping to change at page 10, line 49 ¶
	allowed and disallowed. (See also the migration issues described		allowed and disallowed. (See also the migration issues described
	under Section 4.)		under Section 4.)
	8. References		8. References
	8.1. Normative References		8.1. Normative References
	[FRAMEWORK]		[FRAMEWORK]
	Saint-Andre, P. and M. Blanchet, "Precis Framework:		Saint-Andre, P. and M. Blanchet, "Precis Framework:
	Handling Internationalized Strings in Protocols", draft-		Handling Internationalized Strings in Protocols", draft-
	ietf-precis-framework-06 (work in progress), September		ietf-precis-framework-07 (work in progress), March 2013.
	2012.
	[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, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO		[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
	10646", STD 63, RFC 3629, November 2003.		10646", STD 63, RFC 3629, November 2003.
	[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234, January 2008.		Specifications: ABNF", STD 68, RFC 5234, January 2008.
	skipping to change at page 12, line 12 ¶		skipping to change at page 12, line 38 ¶
	o As recommended in the PRECIS framwork, changed the Unicode		o As recommended in the PRECIS framwork, changed the Unicode
	normalization form from NFKC to NFC.		normalization form from NFKC to NFC.
	o Some Unicode code points that were mapped to nothing in RFC 4013		o Some Unicode code points that were mapped to nothing in RFC 4013
	are simply disallowed by PRECIS.		are simply disallowed by PRECIS.
	Appendix B. Acknowledgements		Appendix B. Acknowledgements
	Thanks to Yoshiro YONEYA and Takahiro NEMOTO for implementation		Thanks to Yoshiro YONEYA and Takahiro NEMOTO for implementation
	feedback. Thanks also to Marc Blanchet, Joe Hildebrand, Alan DeKok,		feedback. Thanks also to Marc Blanchet, Joe Hildebrand, Alan DeKok,
	Simon Josefsson, Jonathan Lennox, Matt Miller, Pete Resnick, and		Simon Josefsson, Jonathan Lennox, Matt Miller, Chris Newman, Pete
	Andrew Sullivan for their input regarding the text.		Resnick, Andrew Sullivan, and Nico Williams for their input.
	This document borrows some text from RFC 4013 and RFC 6120.		This document borrows some text from RFC 4013 and RFC 6120.
	Authors' Addresses		Authors' Addresses
	Peter Saint-Andre		Peter Saint-Andre
	Cisco Systems, Inc.		Cisco Systems, Inc.
	1899 Wynkoop Street, Suite 600		1899 Wynkoop Street, Suite 600
	Denver, CO 80202		Denver, CO 80202
	USA		USA
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