  By combining the one-way coupled chaotic map lattice system with a
bit-reverse operation, we construct a new cryptosystem which is extremely
sensitive to the system parameters even for low-dimensional systems. The
security of this new algorithm is investigated and mechanism of the sensitivity
is analyzed. We further apply this cryptosystem to the public channel
cryptography, based on "Merkle's puzzles", by employing it both as
pseudo-random-number (PN) generators and symmetric encryptor. With the
properties of spatiotemporal chaos, the new scheme is rich with new features
and shows some advantages in comparison with the conventional ones.
