What Is a Digital Signature?

What Is a Digital Signature?

A digital signature is a cryptographic mechanism used to verify the authenticity and integrity of digital data. We may consider it as a digital version of the ordinary handwritten signatures, but with higher levels of complexity and security. To learn how digital signatures work, we need to understand the basics of hash functions and public-key cryptography.

Hash functions

The process of hashing involves transforming data of any size into a fixed-size output

Use cases

Digital signatures can be applied to various kinds of digital documents and certificates

Electronic signatures vs. digital signatures

Digital signatures refer to one particular kind of electronic signatures – which refer to any electronic method of signing documents and messages.

Closing thoughts

Hash functions and public-key cryptography are at the core of digital signature systems

Verifying

If Alice writes a message to Bob, hashes it, and then combines the hash value with her private key to generate a digital signature, the signature will work as a unique digital fingerprint of that particular message.

Public-key cryptography (PKC)

PKC refers to a cryptographic system that makes use of a pair of keys: one public key and one private key.

Why are digital signatures important?

Digital signatures are often used to achieve three results: data integrity, authentication, and non-repudiation

Limitations

The major challenges faced by digital signature schemes rely on at least three requirements: Algorithm, Private Key and Implementation

Hashing the data

This is done by submitting the data through a hashing algorithm so that a hash value is generated (i.e., the message digest).

Signing

After the information is hashed, the sender of the message needs to sign it

Source

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