concept rsa in category cryptography

This is an excerpt from Manning's book Real-World Cryptography MEAP V09. Login to get full access to this book.

The invention of the Diffie-Hellman key exchange algorithm was quickly followed by the invention of the RSA algorithm named after Ron Rivest, Adi Shamir, and Leonard Adleman. RSA contains two different primitives: a public-key encryption algorithm (or asymmetric encryption) and a (digital) signature scheme. Both primitives are part of the larger class of cryptographic algorithms called asymmetric cryptography. In this section we will explain what these primitives do, and how they can be useful.

A year after in 1977, the first signature algorithm called RSA is introduced, along with the RSA asymmetric encryption algorithm (which you learned about in chapter 6). RSA for signing is the first algorithm we’ll talk about in this section.

Figure 7.13. To sign with RSA, we simply do the inverse of the RSA encryption algorithm: we exponentiate the message with the private exponent, and to verify we exponentiate the signature with the public exponent (which returns back to the message).