Gold key

In fiction, a gold key is a special token granting access to and control of a mythical or ultra-private or secret bank account or vault, such as a Swiss bank account. In reality, the key is often a code word and accounts are not completely anonymous. A real "gold key" need not be made of or colored gold, or even a key. If it is a key it may not fit any lock; the keys are important as authentication tokens, not always as literal keys.