Question

What are digital signatures? How do they work?

Short answer

Digital signatures are cryptographic tools used to verify the authenticity of digital messages or documents. They work using a three-step process: document hashing, private key encryption (which creates the digital signature), and signature verification.

Step-by-step solution

Definition of Digital Signatures

Digital signatures are a cryptographic tool utilized to confirm the authenticity and integrity of digital documents or messages. It is akin to a handwritten signature, but much safer as it is nearly impossible to forge. They provide an additional level of security by ensuring that a message or document was not altered during transmission.

Working of Digital Signatures

Digital signatures work with the help of public key cryptography. The process has three steps: \n\n1. Document Hashing: The original document or message is hashed, creating a fixed-length series of numbers and letters. Because a small change in the document produces a dramatic change in the hash, it helps in verifying the document’s integrity.\n\n2. Private Key Encryption: The generated hash is then encrypted with the signer's private key, creating the digital signature.\n\n3. Verification: The signed document, the signer's public key and the digital signature are transmitted to the receiver. The receiver regenerates the hash using the document and the public key. If the regenerated hash matches the transmitted hash (decrypted with the public key), the signature is verified and the document is authentic and unaltered.