Certification-service-provider key length

This is the length of the key used by the certification-service-provider to sign certificates.
Key length alone does not determine the quality of the signature procedure. The key type is also important in this context: For example, the Appendix of the Signature Ordinance requires a key length of at least 1020 bits for the RSA or DSA algorithm for secure electronic signatures, while only 160 bits are required for DSA variants based on elliptical curves.