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Simple Authentication and Security Layer

From Wikipedia, the free encyclopedia

Simple Authentication and Security Layer (SASL) is a framework for authentication and data security in Internet protocols. It decouples authentication mechanisms from application protocols, in theory allowing any authentication mechanism supported by SASL to be used in any application protocol that uses SASL. Authentication mechanisms can also support proxy authorization, a facility allowing one user to assume the identity of another. They can also provide a data security layer offering data integrity and data confidentiality services. DIGEST-MD5 provides an example of mechanisms which can provide a data-security layer. Application protocols that support SASL typically also support Transport Layer Security (TLS) to complement the services offered by SASL.

John Gardiner Myers wrote the original SASL specification (RFC 2222) in 1997. In 2006, that document was replaced by RFC 4422 authored by Alexey Melnikov and Kurt D. Zeilenga. SASL, as defined by RFC 4422 is an IETF Standard Track protocol and is, as of 2006, a Proposed Standard.

SASL mechanisms

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A SASL mechanism implements a series of challenges and responses. Defined SASL mechanisms[1] include:

EXTERNAL
where authentication is implicit in the context (e.g., for protocols already using IPsec or TLS)
ANONYMOUS
for unauthenticated guest access
PLAIN
a simple cleartext password mechanism, defined in RFC 4616
OTP
a one-time password mechanism. Obsoletes the SKEY mechanism.
SKEY
an S/KEY mechanism.
CRAM-MD5
a simple challenge-response scheme based on HMAC-MD5.
DIGEST-MD5
(historic[2]), partially HTTP Digest compatible challenge-response scheme based upon MD5. DIGEST-MD5 offered a data security layer.
SCRAM
(RFC 5802), modern challenge-response scheme based mechanism with channel binding support
NTLM
an NT LAN Manager authentication mechanism
GS2-
family of mechanisms supports arbitrary GSS-API mechanisms in SASL.[3] It is now standardized as RFC 5801.
GSSAPI
for Kerberos V5 authentication via the GSSAPI. GSSAPI offers a data-security layer.
BROWSERID-AES128
for Mozilla Persona authentication[4]
EAP-AES128
for GSS EAP authentication[5]
GateKeeper (& GateKeeperPassport)
a challenge-response mechanism developed by Microsoft for MSN Chat
OAUTHBEARER
OAuth 2.0 bearer tokens (RFC 6750), communicated through TLS[6]
OAUTH10A
OAuth 1.0a message-authentication-code tokens (RFC 5849, Section 3.4.2)[6]

SASL-aware application protocols

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Application protocols define their representation of SASL exchanges with a profile. A protocol has a service name such as "ldap" in a registry shared with GSSAPI and Kerberos.[7]

As of 2012 protocols currently supporting SASL include:

See also

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References

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  1. ^ "Simple Authentication and Security Layer (SASL) Mechanisms". iana.org.
  2. ^ RFC 6331
  3. ^ Simon Josefsson. "Using GSS-API Mechanisms in SASL: The GS2 Mechanism Family".
  4. ^ Luke Howard. "A SASL and GSS-API Mechanism for the BrowserID Authentication Protocol".
  5. ^ Sam Hartman. "A GSS-API Mechanism for the Extensible Authentication Protocol".
  6. ^ a b A Set of Simple Authentication and Security Layer (SASL) Mechanisms for OAuth. IETF. August 2015. doi:10.17487/RFC7628. RFC 7628. Retrieved October 7, 2016.
  7. ^ "Generic Security Service Application Program Interface (GSSAPI)/Kerberos/Simple Authentication and Security Layer (SASL) Service Names". iana.org.
  8. ^ "Request for allocation of new security type code for SASL auth". realvnc.com.
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