The RsaOaepParams object represents the object that should be passed as the algorithm parameter into the encrypt and decrypt operation when using the RSA-OAEP algorithm.
It’s an array of bytes that does not itself need to be encrypted but which should be bound to the ciphertext. A digest of the label is part of the input to the encryption operation. Unless your application calls for a label, you can just omit this argument, and it will not affect the security of the encryption operation.