  Quantum steganography is the study of hiding secret quantum information by
encoding it into what an eavesdropper would perceive as an innocent-looking
message. Here we study an explicit steganographic encoding for Alice to hide
her secret message in the syndromes of an error-correcting code, so that the
encoding simulates a given noisy quantum channel. We calculate achievable rates
of steganographic communication over noiseless quantum channels using this
encoding. We give definitions of secrecy and reliability for the communication
process, and with these assumptions derive upper bounds on the amount of
steganographic communication possible, and show that these bounds match the
communication rates achieved with our encoding. This gives a steganographic
capacity for a noiseless channel emulating a given noisy channel.
