Make this a certification signature.

[C#]
void Certify()

[Visual Basic]
Sub Certify()

may throw Exception()

Make this a certification signature.

A document may contain at most one certification signature.

A certification signature applies to the entire document as a whole and is used to determine document level integrity.

Typically a certification signature is used by the author of a document to freeze the document and specify in what ways it may be modified.

Then, if the author has allowed it, other people may apply approval signatures to the frozen document.

None.