Home / The record / Discrete logarithm mechanisms

This family moves the discrete logarithm problem to a composite modulus, which changes both the arithmetic and the trust model. It keeps the coupon strategy for the claimant and adds a second mode with its own key size, so the parameter record has to say which mode a deployment uses.

What it asks

Record the mode, the modulus construction, the base and the private key size for each deployment, and show that the mode in the design matches the mode in the configuration. Test the transition between modes if both are supported, because a mixed configuration is the usual source of a silent downgrade.

What the revision does

The fourth edition keeps the family and will restate it. No public copy of the revised text exists. The 2009 wording is therefore superseded at publication.

Who it binds

The cryptography owner and the configuration manager.

Evidence an auditor samples

• The mode and parameter record per deployment (configuration management database)
• The modulus and base generation record (key management)
• The test that a mixed mode configuration is rejected (test suite)

The test you can run

Read the design note and the running configuration. If they name different modes, the deployment is unowned.

Common failures

• The mode is a runtime flag with no recorded default.
• A fallback to the weaker mode happens silently on a parameter error.

How to close it

Make the mode explicit in configuration and remove the silent fallback. A downgrade path that nobody chose is the one an attacker will use, and it takes one test to prove it is gone. The artefact that opens the work is the mode and parameter record per deployment; the row is only closed when that artefact is dated and has a person against it.

Where it sits against the 2009 edition

Clause 7 is a 2009 clause that the revision replaces. For Clause 7, the 2009 obligation is the one to evidence until publication; after it, this row is rebuilt against the published text.

For the file, this row closes when the mode and parameter record per deployment exists with a date, a named holder and a pointer, and when the test above has been run and recorded. The cryptography owner and the configuration manager. owns that answer for Clause 7.