Final answer:
To verify the authenticity and integrity of digital documents and messages through digital signatures, cryptographic techniques are used.
Step-by-step explanation:
To verify the authenticity and integrity of digital documents and messages through digital signatures, you can use cryptographic techniques. Digital signatures are created using a private key known only to the signer, and can be verified using a corresponding public key. When a digital document or message is signed, a unique mathematical representation of the document, called a hash, is generated. The hash is then encrypted using the signer's private key, creating the digital signature.
To verify the document's authenticity, the recipient can decrypt the digital signature using the signer's public key, which should match the hash of the received document. If the decrypted hash and the hash of the received document match, it means that the document has not been altered since it was signed by the original sender. This ensures integrity.
For example, let's say Alice wants to send a digitally signed document to Bob. Alice would encrypt the hash of the document using her private key to generate the digital signature. When Bob receives the document and the signature, he can decrypt the signature using Alice's public key. If the decrypted hash matches the hash of the document, Bob can be confident that the document is authentic and has not been tampered with.