Digital Signature
A digital signature is a mathematical technique used to validate the authenticity and integrity of a message, software, or digital document.
Properties: 1. Authenticity. 2. Integrity. 3. Non-repudiation. Standards: X.509, PGP, S/MIME. Algorithms: RSA, ECDSA, EdDSA.
graph LR
Center["Digital Signature"]:::main
Rel_liquidity_pools["liquidity-pools"]:::related -.-> Center
click Rel_liquidity_pools "/terms/liquidity-pools"
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classDef pre fill:#0f172a,stroke:#3b82f6,color:#94a3b8,rx:5,ry:5;
classDef child fill:#0f172a,stroke:#10b981,color:#94a3b8,rx:5,ry:5;
classDef related fill:#0f172a,stroke:#8b5cf6,stroke-dasharray: 5 5,color:#94a3b8,rx:5,ry:5;
linkStyle default stroke:#4b5563,stroke-width:2px;
🧒 Explain Like I'm 5
Imagine you write a letter and then add a secret code at the bottom that only you could know. If anyone changes even one letter in your note, the code won't match anymore, and everyone will know someone messed with it. A [digital signature](/en/terms/digital-signature) is that secret code for everything on the internet, from emails to the apps you download.
🤓 Expert Deep Dive
Technically, creating a digital signature involved two steps: 'Hashing' and 'Encryption'. First, the signer creates a fixed-length 'Digest' of the document using a [hash function](/en/terms/hash-function) like SHA-256. Then, they 'Encrypt' this digest using their 'Private Key'. To verify, the receiver decrypts the signature using the signer's 'Public Key' to reveal the original digest, and then compares it to a new hash they generate from the received document. If they match, the signature is valid. This process ensures 'Non-repudiation'—because only the signer has their private key, they cannot claim someone else signed the document. Common algorithms include RSA, DSA, and the more modern ECDSA (Elliptic Curve Digital Signature Algorithm).