Ensuring Data Authenticity in ID Document Chips through Passive Authentication

In the realm of electronic identification documents, such as passports and national identity cards, maintaining the integrity and authenticity of stored data is paramount. Passive Authentication (PA) serves as a key security measure to verify that the data on an ID document’s chip has not been altered. This method is critical for the trust framework of international travel and identity verification.

This article delves into the verification steps involved in passive authentication and the role of the Country Signing Certification Authority (CSCA) Master List in this process.

Passive Authentication: Overview

Passive Authentication^* is a process designed to confirm the integrity of the data stored on the chip of an ID document. It does not involve any interaction with the document holder. Instead, it checks the digital signatures within the document against public key certificates to ensure that the data has not been tampered with since issuance. This is crucial for preventing unauthorized alterations of sensitive data such as biometric identifiers.

Verification Steps in Passive Authentication

The verification process in Passive Authentication involves several key steps:

Extracting the Document Signer (DS) Certificate

Each ID document’s chip contains a Document Signer Certificate, which is used to sign the data groups within the chip. This certificate itself is signed by the issuing country’s CSCA.

Retrieving the Signed Data (SOD)

The Signed Object (SOD) on the chip contains the hash values of all the data groups, signed by the DS certificate. The SOD ensures that the individual data groups have not been modified since the document was issued.

Verifying the DS Certificate

To trust the authenticity of the SOD, the DS Certificate must be verified against the CSCA Certificate. This step ensures that the DS Certificate, and by extension the SOD, was issued by a legitimate authority.

Validating Hash Values

Each data group’s hash value stored in the SOD is compared against a freshly computed hash of the data group. If all hash values match, it confirms that the data groups have not been altered.

Cross-Checking Revocation and Expiration

It is crucial to check that the DS Certificate and CSCA Certificate have not expired or been revoked at the time of verification. This requires access to up-to-date certificate revocation lists or similar mechanisms.

The Role of the CSCA Master List

The Country Signining Certificate Authority (CSCA) Master List plays a critical role in the ecosystem of document security. It is a collection of digital certificates from CSCAs around the world, distributed by either a trusted international entity like the ICAO or individual countries. Here’s how the CSCA Master List factors into Passive Authentication:

Authenticity Verification

The CSCA Master List provides a repository of trusted CSCA Certificates used to verify the authenticity of DS Certificates found in ID documents.

Current list of Supported Countries and Organizations.

Global Trust

By maintaining a list of CSCAs, countries can cross-verify documents issued by other nations efficiently and securely, fostering international cooperation and trust.

Accessibility

For countries to effectively use Passive Authentication, they must have access to the latest CSCA Master List. This access is typically governed through secure government channels to ensure the integrity of the list.