scope:

The present document specifies CAdES digital signatures. CAdES signatures are built on CMS signatures [7], by incorporation of signed and unsigned attributes, which fulfil certain common requirements (such as the long term validity of digital signatures, for instance) in a number of use cases. The present document specifies the ASN.1 definitions for the aforementioned attributes as well as their usage when incorporating them to CAdES signatures. The present document specifies formats for CAdES baseline signatures, which provide the basic features necessary for a wide range of business and governmental use cases for electronic procedures and communications to be applicable to a wide range of communities when there is a clear need for interoperability of digital signatures used in electronic documents. The present document defines four levels of CAdES baseline signatures addressing incremental requirements to maintain the validity of the signatures over the long term, in a way that a certain level always addresses all the requirements addressed at levels that are below it. Each level requires the presence of certain CAdES attributes, suitably profiled for reducing the optionality as much as possible.