The following article was prepared by Mike Taylor, C.P.M. for distribution to NAPM affiliate newsletters. 
March 28, 2001


Q: Can you tell me what a biometric signature is and compare it to a digital signature?

A digital "signature" is an electronic mark or file which can be attached to messages and used to authenticate the originator. "I know it's really you who sent me this contract because you are the only one who has a password, code or key to be able to generate the authenticating file or encrypt the message." (Public Key Infrastructure (PKI) for example.) You can also have a third party involved (like Verisign) that authenticates the message. "Yep that's the special code we gave the originator to use."

A biometric signature would be like putting your finger print on the message. In this case the software not only records your signature, it also records how you sign (fast, slow, press hard, etc). The resulting file is unique to your biology and can be used to verify that you really are the one who signed.

Biometric "signatures" can also be used to include recognizing other biological characteristics not just a signature.

Either a scanner or software program creates a "signature" to put on messages from a biological characteristic of you. Finger prints, voice prints, retina scans, hand scanners are all being used for this. The "signature" is attached to a document or used as a password just like a digital signature. Since the file is unique to your finger print, it can be verified as really being you instead of someone else.

We have hand scanner locks to get into some buildings here and I'm sure the Lockheed Skunk Works has biometric door locks. The hand scanner transmits the image to a computer which verifies that it is really me before opening the door. Same thing would happen if the image was attached as a file to a document. You could also involve a third party to verify the "signature" was authentic.

Net Nanny ( is now using this type of process so your computer literate kids can't hack their way past your parental lockout of the XFL web site.

Here are some other references:

A leading biometric signature company:

Some cute diagrams:

I love the name this company uses for fingerprint ID:



MLTWEB is assembled and maintained by Michael L. Taylor, C.P.M. 
Materials and articles prepared by Mike may be shared for purchasing education provided that this source is cited and no fee is charged. The rights for any other use are withheld.
Copyright;  Michael L. Taylor, C.P.M.
Last Updated: 11/26/2016