Understanding ECDSA
Prerequisites and audience
In this article, we'll try to understand how ECDSA (Elliptic Curve Digital Signature Algorithm) works.
The version I have in mind is the one used by the Ethereum blockchain. Since my interest lies in security, we'll also explore the signature malleability attack.
I expect you to be familiar with Public Key Cryptography and how it can be used to sign messages, at least conceptually.
You'll only need to know basic math, so abstract algebra is not a requirement. I'll introduce the bare minimum as we go. My exposition will be deliberately unsophisticated, favoring ease of understanding over conciseness and elegance.
The reader I have in mind is someone dissatisfied with the many superficial, hand-wavy explanations of ECDSA often found in articles and books aimed at developers and auditors, but who doesn't have the time or interest to go all the way down the rabbit hole and learn cryptography in a thorough and systematic way.
If you, like me, work in a field where you need to have a working knowledge of multiple disciplines, you'll probably appreciate this kind of compromise.
Finally, this might also serve as an introduction to the topic before you turn to more serious and academic literature.