Signature

A digital signature is a secure way to prove that a piece of digital data comes from a specific person or entity—somewhat like signing a document, but far more tamper-resistant. When you digitally sign something, it’s not just a stamp of approval; the signature is created using advanced cryptography, ensuring it’s unique to both the content and the signer.

Here’s how it works: If you sign the message “Hello,” your signature won’t work for “Hey” or any altered version. That’s because the signature is mathematically tied to the exact data being signed, making it nearly impossible to forge or reuse on different content.

A typical digital signature setup involves three things: the data itself, the signer’s public key, and the actual signature. The public key acts as a kind of username that can be shared with anyone, letting others check the signature without needing any secret information. Only the private key, which isn’t shared, can make the signature, but anyone with the public key can verify it. Since the signature is based on a hash of the data, it’s also clear that the data hasn’t been changed since it was signed. Digital signatures are commonly used for verifying documents, emails, software, and more—offering authenticity and integrity in the digital world.