The present document specifies procedures for: • the creation of AdES digital signatures (specified in ETSI EN 319 122-1 [i.2], ETSI EN 319 132-1 [i.4], ETSI EN 319 142-1 [i.6] respectively); • establishing whether an AdES digital signature is technically valid; whenever the AdES digital signature is based on public key cryptography and supported by Public Key Certificates (PKCs). To improve readability of the present document, AdES digital signatures are meant when the term signature is being used. The present document introduces general principles, objects and functions relevant when creating or validating signatures based on signature creation and validation constraints and defines general classes of signatures that allow for verifiability over long periods.