What I've tried:
var b = DOpus.Create.Blob().copyFrom('I want to be hashed!');
var hash = DOpus.FSUtil().Hash(b, 'sha1');
I get this error:
Invalid procedure call or argument
EDIT:
Figured it out:
var b = DOpus.Create.Blob();
b.copyFrom('I want to be hashed!');
var hash = DOpus.FSUtil().Hash(b, 'sha1');