Adobe PDF provides two types of digital signatures: standard and certification signatures. Documents with a certified digital signature are significantly different from those signed with a regular PDF digital signature. Signatures that certify a PDF are called certifying signatures.

A PDF document signed with a CDS certificate carries the security assurance of the issuing Certification Authority. Only the first person to sign a PDF can add a certifying signature. A certifying signature attests to the contents of the document and allows the signer to specify the types of changes allowed for the document to remain certified.

With non-certifying digital signatures, a user must explicitly trust the author of a document or trust all identities in the Microsoft Certificate Store. With certifying signatures chained to the Adobe root certificate, trust is built into the Adobe software. No additional software or configuration is required to validate its authenticity.

Benefits of certifying with BlueRidge

BlueRidge provides a way t easily check the authenticity of issued PDF documents. The longevity of digitally signed documents with embedded CRL or OCSP responses also aids long term document archival and auditing. There is no need for additional software or swapping trusted CA's or special configuration for time-stamping and CRL or OCSP. It's already integrated. If digitally signed, with a valid timestamp and revocation check, your signature shall remain valid even after the certificate has expired or even if it was revoked after the fact. The OCSP/CRL and time stamping features are provided in the base price of the service.

In Adobe Reader, Blue Ribbon, Question Mark and Red X trust messaging allow users to determine if the certified PDF is from a legitimate source or not. BlueRidge enables document authors to certify PDF files, which automatically validate using free Adobe Reader 6.0+.

When a certified PDF is opened the document as it existed at the time it was certified is compared to the document which is being viewed, including all incremental changes. If necessary, a modification analysis is done and the recipient is notified if there have been modifications that were prohibited by the author. Recipients simply need to open the document using the free Adobe Reader to instantly understand if the authenticity of the document can be trusted. Blue Ribbon, Question Mark and Red X trust messaging allow users to determine if the document is from a legitimate source or not. By selecting signature properties recipients can view additional information, such as the signing certificate, OCSP/CRL and timestamp details. The recipient needs no special software or special configuration, just Adobe Reader 6.0+ to validate the document. In Adobe Reader 8.1 the blue security bar was introduced to ensure an even greater level of trust.