Part 1: General - Computer Security Resource Center - National ...

March, 2007
4. The public key, key use, parameters, validity assurance information, and assurance of
possession are provided to the RA or CA along with a claimed identity. The RA or CA
delegates the verification of the public key owner’s identity to another trusted process
(e.g., an examination of the public key owner’s identity by the U.S. postal service when
delivering registered mail). Upon receiving a request for certification, the RA or CA
generates and sends unique, unpredictable information (e.g., an authenticator or
cryptographic key) to the requestor using the trusted process (e.g., a courier). The trusted
process verifies the identity of the requestor prior to delivery of the information provided
by the RA or CA. The owner uses this information to prove that the trusted process
succeeded, and the RA or CA delivers the certificate to the owner. The information
should be destroyed by the key owner as specified in Section 8.3.4 upon receiving
confirmation that the certificate has been successfully generated. (The RA or CA may
maintain this information for auditing purposes, but should not accept further use of the
unique identifier to prove identity.)
In cases involving an RA, upon receipt of all information from the requesting entity (i.e., the
owner of the new public key), the RA forwards the relevant information to a CA for certification.
The RA and CA in combination shall perform any validation or other checks required for the
algorithm with which the public key will be used (e.g., public key validation) prior to issuing a
certificate. The CA should indicate the checks or validations that have been performed (e.g., in
the certificate, or in the CA policy or practices statement). After generation, the certificate is
distributed manually or electronically to the RA, the public key owner, or a certificate repository
(i.e., a directory) in accordance with the CA’s certificate practices statement.
8.1.5.1.1.3 General Distribution
Public keys may be distributed to entities other than an RA or CA in several ways. Distribution
methods include:
1. Manual distribution of the public key itself by the owner of the public key (e.g., in a face
to face transfer, or by a bonded courier); the mandatory assurances listed in Section
8.1.5.1.1 shall be provided to the recipient prior to the use of the public key
operationally.
2. Manual (e.g., in a face to face transfer or by receipted mail) or electronic distribution of a
public key certificate by the public key owner, the CA, or a certificate repository (i.e., a
directory). The mandatory assurances listed in Section 8.1.5.1.1 that are not provided by
the CA (e.g., public key validation) shall be provided to or performed by the receiver of
the public key prior to the use of the key operationally.
3. Electronic distribution of a public key (e.g., using a communication protocol with
authentication and content integrity) in which the distributed public key is protected by a
certified key pair owned by the entity distributing the public key. The mandatory
assurances listed in Section 8.1.5.1.1 shall be provided to the receiving entity prior to the
use of the public key operationally.
8.1.5.1.2 Distribution of Ephemeral Public Keys
When used, ephemeral public keys are distributed as part of a secure key agreement protocol.
The key agreement process (i.e., the key agreement scheme + the protocol + key confirmation +
any associated negotiation + local processing) should provide a recipient with the assurances
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