﻿Digital signatures employ a type of asymmetric cryptography. 
For messages sent through an insecure channel, a properly implemented 
digital signature gives the receiver reason to believe the message was 
sent by the claimed sender. Digital signatures are equivalent to traditional 
handwritten signatures in many respects; properly implemented digital 
signatures are more difficult to forge than the handwritten type. 
Digital signature schemes in the sense used here are cryptographically based, 
and must be implemented properly to be effective. Digital signatures can 
also provide non-repudiation, meaning that the signer cannot successfully 
claim they did not sign a message, while also claiming their private key 
remains secret; further, some non-repudiation schemes offer a time stamp 
for the digital signature, so that even if the private key is exposed, 
the signature is valid nonetheless. Digitally signed messages may be 
anything representable as a bitstring: examples include electronic mail, 
contracts, or a message sent via some other cryptographic protocol.