A Colorado Facsimile Signature Certificate (COF SC) is a document that is used to validate a signature on a document that is sent electronically. It is issued by the Colorado Secretary of State and is designed to ensure the integrity and authenticity of an electronically transmitted document. The COF SC verifies the identity of the signer and acts as a legal substitute for an original signature. There are two types of Colorado Facsimile Signature Certificates: Individual and Corporate. An Individual COF SC is used to certify a signature on an electronically transmitted document that is signed by a single person. A Corporate COF SC is used to certify a signature on an electronically transmitted document that is signed by two or more individuals.