AU-10

AU-10 NON-REPUDIATION

Overview

Number	Title	Impact	Priority	Subject Area
AU-10	Non-Repudiation	HIGH	P2	Audit And Accountability

Instructions
The information system protects against an individual (or process acting on behalf of an individual) falsely denying having performed Assignment: organization-defined actions to be covered by non-repudiation.

Guidance
Types of individual actions covered by non-repudiation include, for example, creating information, sending and receiving messages, approving information (e.g., indicating concurrence or signing a contract). Non-repudiation protects individuals against later claims by: (i) authors of not having authored particular documents; (ii) senders of not having transmitted messages; (iii) receivers of not having received messages; or (iv) signatories of not having signed documents. Non-repudiation services can be used to determine if information originated from a particular individual, or if an individual took specific actions (e.g., sending an email, signing a contract, approving a procurement request) or received specific information. Organizations obtain non-repudiation services by employing various techniques or mechanisms (e.g., digital signatures, digital message receipts).

Guidance

Types of individual actions covered by non-repudiation include, for example, creating information, sending and receiving messages, approving information (e.g., indicating concurrence or signing a contract). Non-repudiation protects individuals against later claims by: (i) authors of not having authored particular documents; (ii) senders of not having transmitted messages; (iii) receivers of not having received messages; or (iv) signatories of not having signed documents. Non-repudiation services can be used to determine if information originated from a particular individual, or if an individual took specific actions (e.g., sending an email, signing a contract, approving a procurement request) or received specific information. Organizations obtain non-repudiation services by employing various techniques or mechanisms (e.g., digital signatures, digital message receipts).

Enhancements

AU-10 (1) Association Of Identities

This control enhancement supports audit requirements that provide organizational personnel with the means to identify who produced specific information in the event of an information transfer. Organizations determine and approve the strength of the binding between the information producer and the information based on the security category of the information and relevant risk factors.

The information system:

AU-10 (1)(a)

Binds the identity of the information producer with the information to Assignment: organization-defined strength of binding; and

AU-10 (1)(b)

Provides the means for authorized individuals to determine the identity of the producer of the information.

AU-10 (2) Validate Binding Of Information Producer Identity

This control enhancement prevents the modification of information between production and review. The validation of bindings can be achieved, for example, by the use of cryptographic checksums. Organizations determine if validations are in response to user requests or generated automatically.

The information system:

AU-10 (2)(a)

Validates the binding of the information producer identity to the information at Assignment: organization-defined frequency; and

AU-10 (2)(b)

Performs Assignment: organization-defined actions in the event of a validation error.

AU-10 (3) Chain Of Custody

Chain of custody is a process that tracks the movement of evidence through its collection, safeguarding, and analysis life cycle by documenting each person who handled the evidence, the date and time it was collected or transferred, and the purpose for the transfer. If the reviewer is a human or if the review function is automated but separate from the release/transfer function, the information system associates the identity of the reviewer of the information to be released with the information and the information label. In the case of human reviews, this control enhancement provides organizational officials the means to identify who reviewed and released the information. In the case of automated reviews, this control enhancement ensures that only approved review functions are employed.

The information system maintains reviewer/releaser identity and credentials within the established chain of custody for all information reviewed or released.

AU-10 (4) Validate Binding Of Information Reviewer Identity

This control enhancement prevents the modification of information between review and transfer/release. The validation of bindings can be achieved, for example, by the use of cryptographic checksums. Organizations determine validations are in response to user requests or generated automatically.

The information system:

AU-10 (4)(a)

Validates the binding of the information reviewer identity to the information at the transfer or release points prior to release/transfer between Assignment: organization-defined security domains; and

AU-10 (4)(b)

Performs Assignment: organization-defined actions in the event of a validation error.

AU-10 (5) Digital Signatures

Withdrawn: Incorporated into SI-7.