Data Signatures # (Data) signatures are a cryptographic tool to demonstrate the authenticity of some data. In the narrowest sense, a data signature shows that some signer has used their key to issue a cryptographic statement about some data (such as an email message, or a source code archive). Typically, OpenPGP data signatures signal either authorship (such as “this email has been written by me”), or approval (such as “this project certifies that this source code archive contains an of...