https://www.cyfrin.io/blog/elliptic-curve-digital-signature…
https://www.cyfrin.io/blog/elliptic-curve-digital-signature-algorithm-and-signatures
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The Elliptic Curve Digital Signature Algorithm (ECDSA) is based on Elliptic Curve Cryptography (ECC) and is used to generate keys, authenticate, sign, and verify messages. Signatures provide a means for authentication in blockchain technology, allowing operations, such as sending transactions, to be verified that they have originated from the intended signer. But, how do they work and how are they created?
This article will teach you the basics of cryptography to understand the mechanisms underpinning authentication in Ethereum: ECDSA signatures, why they are used, how they work, and the different uses for ECDSA in Ethereum.
Proof of ownership in Ethereum is achieved using public and private key pairs that are used to create digital signatures. Signatures are analogous to having to provide personal ID when withdrawing from the bank - the person needs to verify that they are the owner of the account.
This is known as public key cryptography (asymmetric encryption- more on this later) and is a cryptographic method that uses a key pair system:
It is difficult (for simplicity, can be assumed impossible) to calculate the private key from the public key, even for a computer (note that there is an exception to this assumption that will be discussed later). This means that knowledge of the private key grants access to the account whereas access to the public key does not.
These public and private key pairs define Ethereum externally owned accounts (EOAs) and provide a means for interacting with the blockchain by signing data and sending transactions, without others being able to access accounts they do not own. An Ethereum address is used as identification and is the last 20 bytes of the hash of the public key controlling the account.
Signatures provide a means of cryptographic authentication in blockchain technology, serving as a unique “fingerprint”, forming the backbone of blockchain transactions. They are used to validate computation performed off-chain and authorize t…