How Digital Signatures Work
Understanding how digital signatures work requires a basic knowledge of cryptographic principles, particularly public key infrastructure (PKI). Here’s a simplified explanation:
1. Key Pair Generation
The process starts with creating a pair of keys: a private key and a public key. The private key is kept confidential by the owner, while the public key is shared publicly.
2. Creating the Signature
When the sender wants to sign a document, they use their private key to create a unique digital signature. This signature is generated using a cryptographic algorithm that combines the private key with the document’s contents.
3. Verifying the Signature
The recipient uses the sender’s public key to verify the digital signature. If the public key successfully verifies the signature, it confirms that the document has not been altered and that it was indeed signed by the sender.
4. Hashing
Hashing is an integral part of the digital signature process. A hash function generates a fixed-size string of characters (the hash) from the document’s contents. This hash is then encrypted with the sender’s private key to create the digital signature.