Cryptography Reference
In-Depth Information
Chapter 10
Digital Signatures
Digital signatures are one of the most important cryptographic tools they and are
widely used today. Applications for digital signatures range from digital certificates
for secure e-commerce to legal signing of contracts to secure software updates. To-
gether with key establishment over insecure channels, they form the most important
instance for public-key cryptography.
Digital signatures share some functionality with handwritten signatures. In par-
ticular, they provide a method to assure that a message is authentic to one user, i.e., it
in fact originates from the person who claims to have generated the message. How-
ever, they actually provide much more functionality, as we'll learn in this chapter.
In this chapter you will learn:
The principle of digital signatures
Security services, that is, the specific objectives that can be achieved by a security
system
The RSA digital signature scheme
The Elgamal digital signature scheme and two extensions of it, the digital signa-
ture algorithm (DSA) and the elliptic curve digital signature algorithm (ECDSA)
