Function esp_idf_svc::sys::mbedtls_mpi_safe_cond_assign

pub unsafe extern "C" fn mbedtls_mpi_safe_cond_assign(
    X: *mut mbedtls_mpi,
    Y: *const mbedtls_mpi,
    assign: u8,
) -> i32

\brief Perform a safe conditional copy of MPI which doesn’t reveal whether the condition was true or not.

\param X The MPI to conditionally assign to. This must point to an initialized MPI. \param Y The MPI to be assigned from. This must point to an initialized MPI. \param assign The condition deciding whether to perform the assignment or not. Must be either 0 or 1: * \c 1: Perform the assignment X = Y. * \c 0: Keep the original value of \p X.

\note This function is equivalent to if( assign ) mbedtls_mpi_copy( X, Y ); except that it avoids leaking any information about whether the assignment was done or not (the above code may leak information through branch prediction and/or memory access patterns analysis).

\warning If \p assign is neither 0 nor 1, the result of this function is indeterminate, and the resulting value in \p X might be neither its original value nor the value in \p Y.

\return \c 0 if successful. \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed. \return Another negative error code on other kinds of failure.