@Override
    protected void engineUpdate(byte input) {
        singleByte[0] = input;
        engineUpdate(singleByte, 0, 1);
    }
Configures the public key algorithm context ({@code EVP_PKEY_CTX}) associated with this
operation.

<p>The default implementation does nothing.

@param ctx reference to the context ({@code EVP_PKEY_CTX}).
common/src/main/java/org/conscrypt/OpenSSLSignature.java