### 4.2.1 Performing identification and authentication functions
The certificate request MAY include all factual information about the Applicant to be included in the Certificate, and such additional information as is necessary for the CA to obtain from the Applicant in order to comply with these Requirements and the CA's Certificate Policy and/or Certification Practice Statement. In cases where the certificate request does not contain all the necessary information about the Applicant, the CA SHALL obtain the remaining information from the Applicant or, having obtained it from a reliable, independent, third-party data source, confirm it with the Applicant. The CA SHALL establish and follow a documented procedure for verifying all data requested for inclusion in the Certificate by the Applicant.
Applicant information MUST include, but not be limited to, at least one Fully-Qualified Domain Name or IP address to be included in the Certificate's `subjectAltName` extension.
[Section 6.3.2](#632-certificate-operational-periods-and-key-pair-usage-periods) limits the validity period of Subscriber Certificates. The CA MAY use the documents and data provided in [Section 3.2](#32-initial-identity-validation) to verify certificate information, or may reuse previous validations themselves, provided that the CA obtained the data or document from a source specified under [Section 3.2](#32-initial-identity-validation) or completed the validation itself no more than 825 days prior to issuing the Certificate. For validation of Domain Names and IP Addresses according to Section 3.2.2.4 and 3.2.2.5, any reused data, document, or completed validation MUST be obtained no more than 398 days prior to issuing the Certificate.
In no case may a prior validation be reused if any data or document used in the prior validation was obtained more than the maximum time permitted for reuse of the data or document prior to issuing the Certificate.
After the change to any validation method specified in the Baseline Requirements or EV Guidelines, a CA may continue to reuse validation data or documents collected prior to the change, or the validation itself, for the period stated in this BR 4.2.1 unless otherwise specifically provided in a ballot.
The CA SHALL develop, maintain, and implement documented procedures that identify and require additional verification activity for High Risk Certificate Requests prior to the Certificate's approval, as reasonably necessary to ensure that such requests are properly verified under these Requirements.
If a Delegated Third Party fulfills any of the CA's obligations under this section , the CA SHALL verify that the process used by the Delegated Third Party to identify and further verify High Risk Certificate Requests provides at least the same level of assurance as the CA's own processes.