diffieHellman.computeSecret(other_public_key[, input_encoding][, output_encoding])
Computes the shared secret using other_public_key as the other party's public key and returns the computed shared secret. The supplied key is interpreted using the specified input_encoding, and secret is encoded using specified output_encoding. Encodings can be 'binary', 'hex', or 'base64'. If the input_encoding is not provided, other_public_key is expected to be a Buffer.
If output_encoding is given a string is