Personal Authentication

Frequently asked questions

• What is a Personal Authentication Certificate (PAC)

  A Personal Authentication Certificate is a digital certificate issued to an individual to confirm their identity online, and is commonly used for secure email, document signing, and two-factor authentication.

• How long does it take to issue?

  • Class 1: Instantly

  • Class 2/3: 1–3 business days after identity verification

• Can I sign PDFs or Word docs with it?

  Yes. Comodo PACs can be used in: Adobe Acrobat/Reader and Microsoft Word/Excel. To sign and validate document authenticity and authorship.

• Is it compatible with Outlook, Gmail, etc.?

  Yes. Comodo PACs work with: Microsoft Outlook, Apple Mail, Thunderbird, Gmail (via S/MIME plugin or supported browser)

• Where is the certificate stored?

  It can be stored in: Your browser’s certificate store, Windows certificate manager, or exported as a .pfx file to be imported elsewhere. A hardware token or USB for extra security (especially for Class 3)

• What are the key use cases?

  • Email encryption & signing (S/MIME)

  • Digital document signing (PDF, Word, etc.)

  • User authentication (VPN, web portals)

  • Client certificate authentication

• What happens if I lose my private key?

  If your key is lost and not backed up, the certificate is unusable. You will need a reissue or replacement (depending on the CA’s policy).

• How is it delivered?

  The certificate is emailed to the verified address and installed in your browser or exported to secure storage (e.g., USB token)

• Is this a qualified e-signature?

  No. Comodo PACs are advanced electronic signatures, not eIDAS-qualified signatures unless combined with specific hardware and jurisdictional compliance.

• Can I renew it before it expires?

  Yes. Renewal is recommended before expiry to avoid service disruption, especially for secure email and authentication uses.

• Can I use it on multiple devices?

  Yes, if you export the certificate with its private key and import it on your other devices (securely).

• What validation is required?

  • Class 1: Email verification only

  • Class 2: Validates individual identity with a government-issued ID

  • Class 3: For higher assurance — may include in-person verification

• Who needs a Personal Authentication Certificate?

  • Professionals who send sensitive emails

  • Employees needing identity verification for secure systems

  • Individuals digitally signing documents

  • Anyone who needs email integrity and encryption

• Is this certificate compliant with regulations?

  Yes. PACs help with compliance in areas like: HIPAA (healthcare email security), GDPR (data integrity), SOX, FISMA, and other data security frameworks

• Do recipients need a certificate to read my email?

  Only encrypted emails require the recipient to also have a certificate. Signed emails can be read by anyone but will show your verified signature.

• Does it protect against phishing or spoofing?

  Yes. By digitally signing emails, it proves the message is genuinely from you and hasn’t been altered—preventing impersonation.

• What encryption does it use?

  Typically uses RSA 2048-bit keys and SHA-2 encryption standards for strong security.

• How long is it valid?

  Typically 1–3 years, depending on your chosen subscription.

• What does it secure?

  • Email: Encrypts and signs emails to ensure privacy and authenticity

  • Documents: Ensures documents aren’t tampered with after signing

  • Authentication: Provides certificate-based login (e.g., to internal apps or portals)