Attested

Full Title or Meme

A statement is Attested if some Trusted Third Party can create a Validated Claim about a User Device used during either Authentication or Authorization.

Context

• The Context in which an Attestation of Security applies is typically during the Validation of the security protection provided to User secrets (such as Credentials) on a User Device.

Problems

• When a secure operation is performed at a user location, the packet returned from that User Device needs to be trusted by the Site that receives it.
• The signing key for that packet from a User Device will have a certificate that binds that signing key to a particular device.
• If the device reports a serial number, or (equivalently) a public key that is unique that that device, that can be used as a tracking number for the owner of the device.
• In 1999 Intel started to ship Pentium Processors with a serial number that created huge public outcry about the privacy implications. They backtracked a lot from their original assertions about security an privacy with a Q&A for their OEMs to address the issues. No company has tried putting a serial number in processors since then.

Solution

• The certificate for the signing key from the User Device, and potentially the configuration information from the device, will need to be Attested by some Trusted Third Party.
• It is recommended that a large number (ca 100,000) devices be equipped with the same public key to avoid privacy concerns. Then the public key is basically the Identifier for the category of User Device.
• Attestation can be complex for programmable computers, or simple for one function User Devices like Security Tokens.
• An example of a single attestation program with associated metadata is described in the FIDO web site.
• When a simple certificate is used, it typically is accompanied by a metadata statement, an example is this one at Yubico.

References

Other internal and external links

1. Synonyms include: Assured Corroborated Validated.