Question 1 Certificate (in the meaning of a qualified digital signature PKI component)... Not yet answered Select one: Marked out of 1 a. ... is always a paper-document in order to prevent the unauthorized changing of it b. ... exists usually only in the form of physical device (as ID-card): neither paper-document nor digital document isn't suitable for a certificate c. ... has usually a dual form - it exists both in a paper-based and digital form d. ... exists usually only as the unique record in trust service database e. ... is always a digitally signed digital document in order to make it available and practically usable in the networked digital world Question 2 A private key is needed... Not yet answered Select one: Marked out of 1 a. ... for both the signer and for all trust services b. ... only for a signer and never for other subjects/persons c. ... for both the signer and for an time-stamp authority d. ... for each person (subject) who verifies the digital signature e. ... for both the signer and for an issuer of a corresponding certificate Question 3 Technical specification of a typical cryptoalgorithm... Not yet answered Select one: Marked out of 1 a. . .. are usually made publicly available, because it's forced by the realizing of algorithm in software solutions b. ... are usually kept secret in order to protect the copyright of algorithms and minimize the fabrication possibilities of algorithms c. ... are usually kept secret in order to minimize their' breaking probability with exhaustive search methods d. ... are usually kept secret in order to additionally protect the confidentiality of encrypted data e. are usually made publicly available, because it increases their' security allowing testing them for all cryptoanalysts in all around the world