Digital Signature

is a cryptographic technique that verifies the authenticity and integrity of a message, document, or transaction.

• It is like a fingerprint.”

1. Two keys are generated: a public and a private.
2. A hash is generated from the document or message.
3. The hash is encrypted with the private key.
4. The hash is appended to the document (along with the public key).
5. The recipient uses the public key to decrypt the hash.
6. A hash for the recipient is generated from the document or message.
7. Both hashes should be equal.

• The idea is not to hide or encrypt the message but to make sure it is the original one.
• A digital signature provides integrity, non-repudiation, and authenticity to the message.
• In a war, when you receive a message, how do you know it was not tampered with by the enemy?