Digital Signature
TLDR: A digital signature is a cryptographic mechanism used to verify the authenticity, integrity, and origin of digital data. It ensures that the data has not been tampered with and confirms the identity of the sender. Widely used in cryptography, digital signatures underpin secure communications, software distribution, and online transactions by leveraging public key infrastructure (PKI).
https://en.wikipedia.org/wiki/Digital_signature
A digital signature is generated using an asymmetric encryption algorithm like RSA, ECDSA, or Ed25519. The sender hashes the original data and encrypts the hash using their private key to create the signature. The recipient decrypts the signature using the sender’s public key and compares it to a newly calculated hash of the original data. A match confirms both the authenticity of the sender and the integrity of the data. This process ensures that the information is trustworthy and has not been altered.
https://www.nist.gov/itl/special-publications/nist-special-publication-800-107
Digital signatures are integral to secure systems such as TLS, Secure Boot, and software signing. For example, a signed software package ensures it originates from a trusted developer and is free from malicious alterations. They are also widely used in legal documents, where electronic signatures ensure non-repudiation. By providing both authentication and data integrity, digital signatures are essential for secure and reliable communication in the digital world.