This is the length of the key used by the signatory.
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.
RUNDFUNK UND TELEKOM
Austrian Regulatory Authority for Broadcasting and Telecommunications
Mariahilfer Straße 77-79, 1060 Vienna, Austria
tel.: +43 1 58058-0