COA sticker

A COA sticker (abbreviation: Certificate of Authenticity) is a sticker that is intended to prove the authenticity of (Microsoft) products. According to Microsoft, this sticker is not a software license in the true sense of the word, but is intended to make it easier to distinguish original software from pirated copies.

Software authenticity certificates often contain a license number that is intended to prove that the software is an original program. Certificates of authenticity usually do not grant a right of use (license) for the software.