Kerberos

This document defines a new pre-authentication mechanism for the Kerberos protocol. The mechanism uses a password-authenticated key exchange (PAKE) to prevent brute-force password attacks, and it may incorporate a second factor.

This document updates the Public Key Cryptography for Initial Authentication in Kerberos (PKINIT) standard (RFC 4556) to remove protocol structures tied to specific cryptographic algorithms. The PKINIT key derivation function is made negotiable, and the digest algorithms for signing the pre-authentication data and the client's X.509 certificates are made discoverable.

These changes provide preemptive protection against vulnerabilities discovered in the future in any specific cryptographic algorithm and allow incremental deployment of newer algorithms.

The triple-DES (3DES) and RC4 encryption types are steadily weakening in cryptographic strength, and the deprecation process should begin for their use in Kerberos. Accordingly, RFC 4757 has been moved to Historic status, as none of the encryption types it specifies should be used, and RFC 3961 has been updated to note the deprecation of the triple-DES encryption types. RFC 4120 is likewise updated to remove the recommendation to implement triple-DES encryption and checksum types.

This document updates RFC 4120, as it specifies an extension in the Kerberos protocol. It defines a new authorization data type, AD-AUTHENTICATION-INDICATOR. The purpose of introducing this data type is to include an indicator of the strength of a client's authentication in service tickets so that application services can use it as an input into policy decisions.

This document defines extensions to the Kerberos protocol to allow a Kerberos client to securely communicate with a Kerberos application service without revealing its identity, or without revealing more than its Kerberos realm. It also defines extensions that allow a Kerberos client to obtain anonymous credentials without revealing its identity to the Kerberos Key Distribution Center (KDC). This document updates RFCs 4120, 4121, and 4556. This document obsoletes RFC 6112 and reclassifies that document as Historic. RFC 6112 contained errors, and the protocol described in that specification is not interoperable with any known implementation. This specification describes a protocol that interoperates with multiple implementations.

This document describes how to further extend the Public Key Cryptography for Initial Authentication in Kerberos (PKINIT) extension (defined in RFC 4556) to exchange an opaque data blob that a Key Distribution Center (KDC) can validate to ensure that the client is currently in possession of the private key during a PKINIT Authentication Service (AS) exchange.

This document specifies two encryption types and two corresponding checksum types for Kerberos 5. The new types use AES in CTS mode (CBC mode with ciphertext stealing) for confidentiality and HMAC with a SHA-2 hash for integrity.

This document specifies a Kerberos authorization data container that supersedes AD-KDC-ISSUED. It allows for multiple Message Authentication Codes (MACs) or signatures to authenticate the contained authorization data elements. The multiple MACs are needed to mitigate shortcomings in the existing AD-KDC-ISSUED container. This document updates RFC 4120.

This document defines the Pseudo-Random Function (PRF) for the Kerberos V mechanism for the Generic Security Service Application Program Interface (GSS-API), based on the PRF defined for the Kerberos V cryptographic framework, for keying application protocols given an established Kerberos V GSS-API security context.

This document obsoletes RFC 4402 and reclassifies that document as Historic. RFC 4402 starts the PRF+ counter at 1; however, a number of implementations start the counter at 0. As a result, the original specification would not be interoperable with existing implementations.

This document describes an information model for Kerberos version 5 from the point of view of an administrative service. There is no standard for administrating a Kerberos 5 Key Distribution Center (KDC). This document describes the services exposed by an administrative interface to a KDC.

This memo documents a method for a Kerberos Key Distribution Center (KDC) to respond to client requests for Kerberos tickets when the client does not have detailed configuration information on the realms of users or services. The KDC will handle requests for principals in other realms by returning either a referral error or a cross-realm Ticket-Granting Ticket (TGT) to another realm on the referral path. The clients will use this referral information to reach the realm of the target principal and then receive the ticket. This memo also provides a mechanism for verifying that a request has not been tampered with in transit. This memo updates RFC 4120. [STANDARDS-TRACK]

This document specifies two encryption types and two corresponding checksum types for the Kerberos cryptosystem framework defined in RFC 3961. The new types use the Camellia block cipher in CBC mode with ciphertext stealing and the CMAC algorithm for integrity protection. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document defines four new options for the Dynamic Host Configuration Protocol for IPv6 (DHCPv6). These options are used to carry configuration information for Kerberos. [STANDARDS-TRACK]

This document describes a protocol, called kx509, for using Kerberos tickets to acquire X.509 certificates. These certificates may be used for many of the same purposes as X.509 certificates acquired by other means, but if a Kerberos infrastructure already exists, then the overhead of using kx509 may be much less.

While not standardized, this protocol is already in use at several large organizations, and certificates issued with this protocol are recognized by the International Grid Trust Federation. This document is not an Internet Standards Track specification; it is published for informational purposes.

The Kerberos 5 network authentication protocol, originally specified in RFC 1510, can use the Data Encryption Standard (DES) for encryption. Almost 30 years after first publishing DES, the National Institute of Standards and Technology (NIST) finally withdrew the standard in 2005, reflecting a long-established consensus that DES is insufficiently secure. By 2008, commercial hardware costing less than USD 15,000 could break DES keys in less than a day on average. DES is long past its sell-by date. Accordingly, this document updates RFC 1964, RFC 4120, RFC 4121, and RFC 4757 to deprecate the use of DES, RC4-HMAC-EXP, and other weak cryptographic algorithms in Kerberos. Because RFC 1510 (obsoleted by RFC 4120) supports only DES, this document recommends the reclassification of RFC 1510 as Historic. This memo documents an Internet Best Current Practice.

The Kerberos protocol provides a framework authenticating a client using the exchange of pre-authentication data. This document describes the use of this framework to carry out One-Time Password (OTP) authentication. [STANDARDS-TRACK]

Currently, channel bindings are implemented using an MD5 hash in the Kerberos Version 5 Generic Security Service Application Programming Interface (GSS-API) mechanism (RFC 4121). This document updates RFC 4121 to allow channel bindings using algorithms negotiated based on Kerberos crypto framework as defined in RFC 3961. In addition, because this update makes use of the last extensible field in the Kerberos client-server exchange message, extensions are defined to allow future protocol extensions. [STANDARDS-TRACK]

The Kerberos 5 KRB-CRED message is used to transfer Kerberos credentials between applications. When used with a secure transport, the unencrypted form of the KRB-CRED message may be desirable. This document describes the unencrypted form of the KRB-CRED message. [STANDARDS-TRACK]

This document specifies how the Kerberos V5 protocol can be transported over the Transport Layer Security (TLS) protocol in order to provide additional security features. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document defines new naming constraints for well-known Kerberos principal names and well-known Kerberos realm names. [STANDARDS- TRACK]

Kerberos is a protocol for verifying the identity of principals (e.g., a workstation user or a network server) on an open network. The Kerberos protocol provides a facility called pre-authentication. Pre-authentication mechanisms can use this facility to extend the Kerberos protocol and prove the identity of a principal.

This document describes a more formal model for this facility. The model describes what state in the Kerberos request a pre-authentication mechanism is likely to change. It also describes how multiple pre-authentication mechanisms used in the same request will interact.

This document also provides common tools needed by multiple pre-authentication mechanisms. One of these tools is a secure channel between the client and the key distribution center with a reply key strengthening mechanism; this secure channel can be used to protect the authentication exchange and thus eliminate offline dictionary attacks. With these tools, it is relatively straightforward to chain multiple authentication mechanisms, utilize a different key management system, or support a new key agreement algorithm. [STANDARDS-TRACK]

This document provides background information regarding large-scale Kerberos deployments in the industrial sector, with the aim of identifying issues in the current Kerberos cross-realm authentication model as defined in RFC 4120.

This document describes some examples of actual large-scale industrial systems, and lists requirements and restrictions regarding authentication operations in such environments. It also identifies a number of requirements derived from the industrial automation field. Although they are found in the field of industrial automation, these requirements are general enough and are applicable to the problem of Kerberos cross-realm operations. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document describes version 2 of the RPCSEC_GSS protocol. Version 2 is the same as version 1 (specified in RFC 2203) except that support for channel bindings has been added. RPCSEC_GSS allows remote procedure call (RPC) protocols to access the Generic Security Services Application Programming Interface (GSS-API). [STANDARDS-TRACK]

This document describes the use of Elliptic Curve certificates, Elliptic Curve signature schemes and Elliptic Curve Diffie-Hellman (ECDH) key agreement within the framework of PKINIT -- the Kerberos Version 5 extension that provides for the use of public key cryptography. This memo provides information for the Internet community.

This document describes the mapping of Generic Security Service Application Program Interface (GSS-API) domain-name-based service principal names onto Kerberos V principal names. [STANDARDS-TRACK]

This document describes an extensibility mechanism for the Kerberos V5 protocol when used over TCP transports. The mechanism uses the reserved high-bit in the length field. It can be used to negotiate TCP-specific Kerberos extensions. [STANDARDS-TRACK]

The Microsoft Windows 2000 implementation of Kerberos introduces a new encryption type based on the RC4 encryption algorithm and using an MD5 HMAC for checksum. This is offered as an alternative to using the existing DES-based encryption types.

The RC4-HMAC encryption types are used to ease upgrade of existing Windows NT environments, provide strong cryptography (128-bit key lengths), and provide exportable (meet United States government export restriction requirements) encryption. This document describes the implementation of those encryption types. This memo provides information for the Internet community.

The Simple Authentication and Security Layer (SASL) is a framework for adding authentication support to connection-based protocols. This document describes the method for using the Generic Security Service Application Program Interface (GSS-API) Kerberos V5 in the SASL.

This document replaces Section 7.2 of RFC 2222, the definition of the "GSSAPI" SASL mechanism. This document, together with RFC 4422, obsoletes RFC 2222. [STANDARDS-TRACK]

This document describes protocol extensions (hereafter called PKINIT) to the Kerberos protocol specification. These extensions provide a method for integrating public key cryptography into the initial authentication exchange, by using asymmetric-key signature and/or encryption algorithms in pre-authentication data fields. [STANDARDS-TRACK]

This document defines a mechanism to enable in-band transmission of Online Certificate Status Protocol (OCSP) responses in the Kerberos network authentication protocol. These responses are used to verify the validity of the certificates used in Public Key Cryptography for Initial Authentication in Kerberos (PKINIT), which is the Kerberos Version 5 extension that provides for the use of public key cryptography. [STANDARDS-TRACK]

This document describes how the Microsoft Internet Explorer (MSIE) and Internet Information Services (IIS) incorporated in Microsoft Windows 2000 use Kerberos for security enhancements of web transactions. The Hypertext Transport Protocol (HTTP) auth-scheme of "negotiate" is defined here; when the negotiation results in the selection of Kerberos, the security services of authentication and, optionally, impersonation (the IIS server assumes the windows identity of the principal that has been authenticated) are performed. This document explains how HTTP authentication utilizes the Simple and Protected GSS-API Negotiation mechanism. Details of Simple And Protected Negotiate (SPNEGO) implementation are not provided in this document. This memo provides information for the Internet community.

This document specifies an extension to the Kerberos protocol as defined in RFC 4120, in which the client can send a list of supported encryption types in decreasing preference order, and the server then selects an encryption type that is supported by both the client and the server. [STANDARDS-TRACK]

This document describes the Kerberized Internet Negotiation of Keys (KINK) protocol. KINK defines a low-latency, computationally inexpensive, easily managed, and cryptographically sound protocol to establish and maintain security associations using the Kerberos authentication system. KINK reuses the Quick Mode payloads of the Internet Key Exchange (IKE), which should lead to substantial reuse of existing IKE implementations. [STANDARDS-TRACK]

This document provides an overview and specification of Version 5 of the Kerberos protocol, and it obsoletes RFC 1510 to clarify aspects of the protocol and its intended use that require more detailed or clearer explanation than was provided in RFC 1510. This document is intended to provide a detailed description of the protocol, suitable for implementation, together with descriptions of the appropriate use of protocol messages and fields within those messages. [STANDARDS-TRACK]

This document defines protocols, procedures, and conventions to be employed by peers implementing the Generic Security Service Application Program Interface (GSS-API) when using the Kerberos Version 5 mechanism.

RFC 1964 is updated and incremental changes are proposed in response to recent developments such as the introduction of Kerberos cryptosystem framework. These changes support the inclusion of new cryptosystems, by defining new per-message tokens along with their encryption and checksum algorithms based on the cryptosystem profiles. [STANDARDS-TRACK]

This document describes a framework for defining encryption and checksum mechanisms for use with the Kerberos protocol, defining an abstraction layer between the Kerberos protocol and related protocols, and the actual mechanisms themselves. The document also defines several mechanisms. Some are taken from RFC 1510, modified in form to fit this new framework and occasionally modified in content when the old specification was incorrect. New mechanisms are presented here as well. This document does NOT indicate which mechanisms may be considered "required to implement". [STANDARDS-TRACK]

The United States National Institute of Standards and Technology (NIST) has chosen a new Advanced Encryption Standard (AES), which is significantly faster and (it is believed) more secure than the old Data Encryption Standard (DES) algorithm. This document is a specification for the addition of this algorithm to the Kerberos cryptosystem suite. [STANDARDS-TRACK]

This memo specifies Microsoft's Windows 2000 Kerberos change password and set password protocols. The Windows 2000 Kerberos change password protocol interoperates with the original Kerberos change password protocol. Change password is a request reply protocol that includes a KRB_PRIV message that contains the new password for the user. This memo provides information for the Internet community.

The goal of this document is to produce a streamlined, fast, easily managed, and cryptographically sound protocol without requiring public key. This memo provides information for the Internet community.

This document describes how Kerberos Version 5 is used with the telnet protocol. It describes an telnet authentication suboption to be used with the telnet authentication option. [STANDARDS-TRACK]

This memorandum describes a method whereby one can use GSS-API (Generic Security Service Application Program Interface) to supply a secure channel between a client and server, authenticating the client with a password, and a server with a public key certificate. [STANDARDS-TRACK]

This document defines a method to encrypt a file transfer using the FTP specification STD 9, RFC 959, "File Transfer Protocol (FTP)", (October

This memo obsoletes [STANDARDS-TRACK]

This document specifies C language bindings for Version 2, Update 1 of the Generic Security Service Application Program Interface (GSS-API), which is described at a language-independent conceptual level in RFC 2743. [STANDARDS-TRACK]

This document proposes the addition of new cipher suites to the TLS protocol to support Kerberos-based authentication. [STANDARDS-TRACK]

This memorandum clarifies various security issues involving the NFS protocol (Version 2 and Version 3 only) and then describes how the Version 2 and Version 3 of the NFS protocol use the RPCSEC_GSS security flavor protocol and Kerberos V5. [STANDARDS-TRACK]

The IDUP-GSS-API extends the GSS-API for applications requiring protection of a generic data unit (such as a file or message) in a way which is independent of the protection of any other data unit and independent of any concurrent contact with designated "receivers" of the data unit. This memo provides information for the Internet community.

This document defines extensions to the FTP specification STD 9, RFC

This specification defines protocols, procedures, and conventions to be employed by peers implementing the Generic Security Service Application Program Interface (as specified in RFCs 1508 and 1509) when using the Simple Public-Key Mechanism. [STANDARDS-TRACK]

This specification defines protocols, procedures, and conventions to be employed by peers implementing the Generic Security Service Application Program Interface (as specified in RFCs 1508 and 1509) when using Kerberos Version 5 technology (as specified in RFC 1510). [STANDARDS-TRACK]

The goal of DASS is to provide authentication services in a distributed environment which are both more secure and easier to use than existing mechanisms. This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard.

This memo defines an Experimental Protocol for the Internet community.