Signature Cells
A cell that represents a model signature is called a "signature cell." It is created and managed as a normal cell in a cell library and then placed in the model that is being signed. What makes a signature cell special is that it is digitally signed. Digitally signing the cell prevents tampering and associates a digital certificate with the cell. Internally, a signature cell contains an embedded cell, which is the cell’s (hidden) signature.
This method of associating a certificate with cell graphics reduces errors in placing signature cells but does not make signature cells more or less secure or trustworthy.