horde/stringprep

Internationalized strings preparation library

v2.0.0beta1 2026-04-12 00:00 UTC

Requires

• php: ^8.1
• ext-iconv: *
• ext-intl: *

LGPL-3.0-only

• Michael Slusarz

• precis
• stringprep
• rfc7564
• rfc3454

README

Unicode string preparation for authentication and protocol identifiers. Provides both legacy RFC 3454 Stringprep and modern RFC 7564 PRECIS profiles, backed by PHP's ext-intl with no bundled vendor dependencies.

Requires PHP 8.1+ and ext-intl.

Stringprep profiles (RFC 3454)

Frozen to Unicode 3.2. Used by older protocol specifications.

Profile	Class	RFC	Purpose
SASLprep	SaslPrepProfile	4013	SASL usernames and passwords
Nameprep	NameprepProfile	3491	Internationalized domain names
iSCSI	IscsiProfile	3722	iSCSI naming
Nodeprep	NodeprepProfile	6122 App A	XMPP node identifiers
Resourceprep	ResourceprepProfile	6122 App B	XMPP resource identifiers
PolicyMIB	PolicyMibProfile	4011	Policy-based management
Trace	TraceProfile	4505	Anonymous SASL

PRECIS profiles (RFC 7564)

Unicode-version-agile. Recommended for new implementations.

Profile	Class	RFC	Purpose
UsernameCaseMapped	UsernameCaseMappedProfile	8265	Usernames (case-insensitive)
UsernameCasePreserved	UsernameCasePreservedProfile	8265	Usernames (case-sensitive)
OpaqueString	OpaqueStringProfile	8265	Passwords
Nickname	NicknameProfile	8266	Chat/display nicknames

Usage

All profiles implement ProfileInterface with the same apply() method:

use Horde\Stringprep\SaslPrepProfile;
use Horde\Stringprep\OpaqueStringProfile;
use Horde\Stringprep\ProfileInterface;

// Legacy stringprep
$saslprep = new SaslPrepProfile();
$username = $saslprep->apply($input, ProfileInterface::MODE_QUERY);

// Modern PRECIS
$opaque = new OpaqueStringProfile();
$password = $opaque->apply($input, ProfileInterface::MODE_STORE);

MODE_STORE (default) rejects unassigned codepoints. MODE_QUERY allows them.

See doc/UPGRADING.md for migration from the bundled lib/ Znerol implementation.