method of verifying origin of a signed file

Methods are provided for generating a certificate, signing files with the certificate and verifying the signing. A first aspect provides, in an electronic data processing device, a method of processing a data file. The method comprises associating a certificate to a data file, the certificate comprising at least one reputation service identifier, signing the data file using a private key associated with the certificate, generating a file identifier based on data comprised by the data file and sending the file identifier to a trusted data vault associated with the certificate. The method further comprises generating a data file token based on the file identifier, signing the data file token with the private key and sending the token to the reputation service for publication associated with the reputation service identifier.