  A new cryptographic tool, anonymous quantum key technique, is introduced that
leads to unconditionally secure key distribution and encryption schemes that
can be readily implemented experimentally in a realistic environment. If
quantum memory is available, the technique would have many features of
public-key cryptography; an identification protocol that does not require a
shared secret key is provided as an illustration. The possibility is also
indicated for obtaining unconditionally secure quantum bit commitment protocols
with this technique.
