Trustmark Definition (TD):
NIEF IDP and AP Attribute Encoding


NameNIEF IDP and AP Attribute Encoding
Publication Date2015-06-19
Trustmark Defining Organization
NameGeorgia Tech Research Institute
Mailing Address75 5th Street NW, Suite 900, Atlanta, GA 30308
DescriptionThis Trustmark Definition adopts the conformance criteria of [NIEF Attr]. This trustmark should only be issued to organizations that are also requesting a trustmark for an appropriate technical interoperability profile, such as NIEF Web Services Attribute Provider SIP Requirements for APs or FICAM SAML SSO Requirements for IDPs.
Target StakeholdersIdentity Provider Organizations, Attribute Provider Organizations, and Relying Parties that require consistently formatted SAML attributes to communicate.
Target RecipientsIdentity Provider Organizations and Attribute Provider Organizations that intend to issue attributes that conform to the NIEF Attribute Encoding Requirements.
Target Relying PartiesFederal, State, and Local Relying Parties that wish to receive NIEF Attributes during SAML SSO or via attribute queries.
Target ProvidersTrust framework providers that are capable of issuing SAML SSO interoperability trustmarks; they must have a fully functional test SAML federation.
Provider CriteriaAny organization or business entity may act as a Trustmark Provider for trustmarks under this Trustmark Definition.
Assessor QualificationsAny individual employed or contracted by the Trustmark Provider may act as the assessor for trustmarks under this Trustmark Definition.
Trustmark Revocation CriteriaFor any trustmark issued under this Trustmark Definition, the Trustmark Provider must revoke the trustmark upon any condition whereby one or more Conformance Criteria cease to be satisfied.
Extension DescriptionThis Trustmark Definition requires no extension data.
Legal NoticeThis document and the information contained herein is provided on an "AS IS" basis, and the Georgia Tech Research Institute disclaims all warranties, express or implied, including but not limited to any warranty that the use of the information herein will not infringe any rights or any implied warranties or merchantability or fitness for a particular purpose. In addition, the Georgia Tech Research Institute disclaims legal liability for any loss incurred as a result of the use or reliance on the document or the information contained herein.
NotesThe Georgia Tech Research Institute (GTRI) has published this document with the support of the National Strategy for Trusted Identities in Cyberspace (NSTIC) via the National Institute of Standards and Technology (NIST). The views expressed herein do not necessarily reflect the official policies of GTRI, NIST or NSTIC; nor does mention of trade names, commercial practices, or organizations imply endorsement by the U.S. Government.

Conformance Criteria (2)

1: SAML Attribute Name

All SAML Attributes from the NIEF Registry transmitted must use the full formal name for the attributes as defined in the NIEF Attribute Registry.


2: SAML Attribute Values

All SAML attribute values must be encoded as XML strings.


Assessment Steps (2)

This assessment is intended to be performed on Identity Providers and Attribute Providers that wish to provide SAML Attributes that conform to the NIEF Attribute Encoding Rules. This assessment is best done in parallel with issuing interoperability trustmarks, otherwise it will require extensive and redundant system software setup.

The assessor's test Service Provider or Attribute Consumer must be trusted by the system being evaluated.

1: Valid Attribute Names (Attribute_Name_Step)

Are all NIEF attributes provided using full formal attribute names as defined by the NIEF Attribute Registry? Please provide a sample SAML Attribute Statement as XML/Text.

Required Artifact(s)
  • Sample SAML Attribute Statement

    A Text/XML sample of a SAML Attribute Statement.

2: Valid Attribute Values (Attribute_Values_Step)

Are all SAML Attribute Values encoded as XML Strings? This requires the type to be specified as string or to not be specified as a different type. Please provide a sample SAML Attribute Statement as XML/Text.

Required Artifact(s)
  • Sample SAML Attribute Statement

    A Text/XML sample of a SAML Attribute Statement.

Issuance Criteria


Sources (1)

NIEF Attribute Encoding Rules 1.0

Terms (24)


An account is used to associate transactional records with an end user or organization. Presence of an account does not necessarily mean that there are credentials (e.g., username and password) associated with the account.


To make a statement about the properties of a user or user's act of authentication.

Authentication Session

Period of time that an end user remains trusted after the end user authenticates. That is because an IDP typically does not require an end user to re-authenticate for every page requested. Each IDP defines its own authentication session duration. If an end user returns to the IDP and an earlier authentication session has expired, the IDP re-authenticates the end user even if single sign-on is in effect.


Mappings of SAML request-response message exchanges onto standard messaging or communication protocols.

Consolidated Metadata

A single XML file containing a top-level root <md:EntitiesDescriptor> containing multiple <md:EntityDescriptor> and/or <md:EntitiesDescriptor> elements.

Credential Service Provider ( CSP )

For the purposes of SAML SSO, they are synonymous with Identity Providers.

Digital Encryption

Private key data encryption that converts data into a form that cannot be easily understood by unauthorized people. Decryption is the process of converting encrypted data back into its original form, so it can be understood. Within the FICAM SAML Profile, encryption pertains to SSL v3 or TLS 1.1 (and higher), encryption and/or XML encryption, depending upon the Level of Assurance.

Digital Signature

An asymmetric key operation where the private key is used to digitally sign an electronic document and the public key is used to verify the signature. Digital signatures provide authentication and integrity protection.


Process of an end user finding a IDP and/or RP.

Extensible Markup Language ( XML )

XML is a specification developed by the W3C that enables the definition, transmission, validation, and interpretation of data between applications and between organizations. In a nutshell, XML describes data and focuses on what data is. XML facilitates technical interoperability, and is used in identity management standards such as SAML (e.g., to convey information in a SAML assertion).

Federal Identity, Credential, and Access Management ( FICAM )

Federal Identity, Credential, and Access Management (ICAM) requires a mechanism to assess the identity management standards against applicable federal requirements, policies, and laws.

Holder-of-Key Assertion

A holder-of-key assertion contains a reference to a public key (corresponding to a private key) or a symmetric key possessed by the end user. The RP requires the end user to prove possession of the private key or secret that is referenced in the assertion. In proving possession, the end user also proves that he or she is the rightful owner of the assertion.

Identity Provider ( IDP )

For the purposes of SAML SSO, they are synonymous with Credential Service Providers. A kind of service provider that creates, maintains, and manages identity information for principals and provides principal authentication to other service providers (relying parties) within a federation, such as with web browser profiles.


Information shared between endpoints (e.g., RP, IDP) necessary for technical interoperation.

National Identity Exchange Federation ( NIEF )

The National Identity Exchange Federation (NIEF) is a collection of government agencies and other organizations in the U.S. that have come together to share sensitive information, subject to applicable access controls, under a common, well-defined, standards-based trust framework.


Ability to maintain data.

Protected Session

A session wherein messages between two participants are encrypted and integrity is protected using a set of shared secrets called session keys. A participant is said to be authenticated if, during the session, he, she or it proves possession of a long term token in addition to the session keys, and if the other party can verify the identity associated with that token. If both participants are authenticated, the protected session is said to be mutually authenticated. One way to implement a protected session is SSL/TLS, which is required for this Profile.

Pseudonymous Identifier

Private end user pseudonym that will only be used with one site. The site will always know it's you when you come back, but it won't be able to look up any other information about you, or correlate your profile with other sites.

Relying Party ( RP )

A system entity (i.e., stand-alone system or group of applications that rely on a central authentication system) that decides to take an action based on information from another system entity. For example, a SAML Relying Party depends on receiving assertions from an asserting party (e.g., a SAML Identity Provider) about a subject. A Relying Party is also referred to as a Service Provider.

Security Assertion Markup Language ( SAML )

The set of specifications describing security assertions that are encoded in XML, profiles for attaching the assertions to various protocols and frameworks, the request/response protocol used to obtain the assertions, and bindings of this protocol to various transfer protocols (for example, SOAP and HTTP). SAML addresses web single sign-on, web services authentication, attribute exchange, authorization, non-repudiation, and secure communications. SAML defines assertion message formats that are referenced in Liberty Alliance, Shibboleth, WS-Security, and other specifications. SAML has become the standard web SSO identity management solution. Several versions have been released to date, including SAML 1.0, SAML 1.1, and SAML 2.0. The Organization for the Advancement of Structured Information Standards (OASIS) oversees SAML.

Security Token Service ( STS )

An STS provides a standards-based method of converting security tokens across different formats.

Service Provider ( SP )

For the purpose of SAML SSO, they are synonymous with Relying Parties. Service Providers generate SAML AuthnRequests, provide users with discovery interfaces, consume SAML Responses, and generally provide some sort of service or capability for a user.

Signature Verification

The process of checking the digital signature by reference to the original message and a given public key, thereby determining whether the digital signature was created for that same message using the private key that corresponds to the referenced public key.

Single Sign-on ( SSO )

Once an end user has authenticated their identity at an IDP, he or she may, by their choice, move among RPs that interoperate with the IDP without re-authenticating. In other words, the end user is seamlessly logged into any other RP that interoperates with the IDP. For privacy considerations, end users must take explicit actions to opt-in to SSO. In addition, SSO is in effect only for the duration of the end user's current browser session and authentication session.