Aclass of cryptographic algorithms which requires two separate keys, one of which is secret (or private) and one of which is public is called?

Asymmetric-key encryption or algorithm.

Explanation:

Cryptographic algorithms are a step-by-step approach of manipulating data by basically converting it from its raw plain format(which is a readable format) to a protected form. A cryptographic algorithm can also be called cipher. The readable format is also called plaintext while the encrypted or protected format is referred to as a ciphertext.

There are various classes of cipher, one of which is asymmetric-key algorithm or encryption, also known as public key encryption. In this algorithm, a pair of keys, one is called a public key and the other a private key, are involved. Each public key is made open to anyone and the corresponding private key is made confidential (secret).

PS: In encryption, a key is just a random string of data bits majorly used for arranging and disarranging data.

Hope this helps!