Digital signatures rely on which type of cryptography?

Digital signatures rely on which type of cryptography?

• A. Symmetric-key cryptography
• B. Asymmetric-key cryptography
• C. Hash-only methods
• D. Public-key cryptography without private keys

Answer: (B)

Digital signatures rely on asymmetric-key cryptography. In this approach, a pair of keys is used: a private key kept by the signer and a public key shared openly. The signer creates a digest of the message with a hash function and signs that digest with the private key. Anyone can verify the signature using the signer’s public key by checking it against the message’s hash, confirming who signed it and that the message hasn't been altered. This setup also provides non-repudiation, since only the private key holder could have created the signature. Symmetric-key cryptography uses the same secret key for both signing and verification, which doesn’t support non-repudiation. Hash-only methods protect integrity but don’t authenticate the signer. Public-key cryptography without private keys isn’t viable for signing because signing requires the private key.

Digital signatures rely on asymmetric-key cryptography. In this approach, a pair of keys is used: a private key kept by the signer and a public key shared openly. The signer creates a digest of the message with a hash function and signs that digest with the private key. Anyone can verify the signature using the signer’s public key by checking it against the message’s hash, confirming who signed it and that the message hasn't been altered. This setup also provides non-repudiation, since only the private key holder could have created the signature. Symmetric-key cryptography uses the same secret key for both signing and verification, which doesn’t support non-repudiation. Hash-only methods protect integrity but don’t authenticate the signer. Public-key cryptography without private keys isn’t viable for signing because signing requires the private key.