Final answer:
An asymmetric key algorithm requires two separate keys, a public and a private key, where the public key encrypts data and is openly shared while the private key decrypts and is kept secure. It doesn't require a secure exchange of a secret key, unlike symmetric key cryptography.
Step-by-step explanation:
The question addresses an asymmetric key algorithm, which is a type of encryption method used in computer security and cryptography. Such algorithms are characterized by a pair of keys: a public key and a private key.
Answering the given question, the two descriptions that correctly define an asymmetric key algorithm are:
- Requires two separate keys - This is true because in asymmetric cryptography, two different keys are used for encryption and decryption. The public key is used for encryption and can be shared openly, while the private key is used for decryption and must be kept secure by the owner.
- Does not require secure exchange of a secret key - Since the public key does not need to be kept secret and can be freely distributed, there is no requirement for a secure exchange of a secret key. This contrasts with symmetric key cryptography, where the same key must be securely shared between parties.
The other options provided in the question are not applicable to asymmetric key algorithms:
- Encryption and decryption is performed using the same key - This describes symmetric key cryptography, not asymmetric.
- Cannot be used to ensure non-repudiation - In fact, asymmetric key algorithms can be used to ensure non-repudiation through digital signatures, proving that a message was sent by a particular sender.