(1) For the purposes of sections 21 and 22, it is presumed that an electronic signature is as reliable as is appropriate where—
(a) the means of creating the electronic signature is linked to the signatory and to no other person;
(b) the means of creating the electronic signature was under the control of the signatory and of no other person;
(c) any alteration to the electronic signature made after the time of signing is detectable; and
(d) the purpose of the legal requirement for a signature is to provide assurance as to the integrity of the information to which it relates, any alteration made to that information after the time of signing is detectable.
(2) Subsection (1) does not prevent any person from proving on other grounds or by other means that an electronic signature—
(a) is as reliable as is appropriate; or
(b) is not as reliable as is appropriate.