Functions of ECDH and ECDSA

CD.

ECDH (Elliptic Curve Diffie-Hellman) and ECDSA (Elliptic Curve Digital Signature Algorithm) are two important cryptographic protocols used in modern security systems. Here are their functions:

1. Key exchange (Answer D): ECDH is a key exchange protocol that allows two parties to establish a shared secret key over an insecure communication channel. The protocol is based on the Diffie-Hellman key exchange algorithm, but uses elliptic curve cryptography (ECC) to provide a higher level of security and efficiency. ECDH is widely used in VPN (Virtual Private Network) and TLS (Transport Layer Security) protocols to ensure secure communication between clients and servers.

2. Digital signature (Answer C): ECDSA is a digital signature algorithm based on elliptic curve cryptography. It is used to verify the authenticity and integrity of digital messages or documents. ECDSA generates a digital signature that can only be produced by the owner of the private key, and can be verified by anyone who has access to the corresponding public key. ECDSA is widely used in secure communication protocols, such as TLS and SSH (Secure Shell), to authenticate clients and servers.

Nonrepudiation (Answer A) is a property of a secure system that ensures that a user cannot deny having performed an action or sent a message. While ECDH and ECDSA do provide some level of nonrepudiation, it is not their primary function.

Revocation (Answer B) is a mechanism used to revoke or invalidate a digital certificate or key pair that has been compromised or is no longer valid. Again, while ECDH and ECDSA can be used in conjunction with revocation mechanisms, it is not their primary function.

Encryption (Answer E) is a process of transforming plain text into ciphertext to ensure confidentiality. While ECDH and ECDSA can be used to establish a shared secret key for encryption, it is not their primary function.