Jon Lech Johansen, the infamous cracker of CSS (the encryption used for commercial DVDs), has
cracked the Airport Express crypto which uses a combination of AES and RSA to encrypt the audio stream.
Jon has also released a small tool called
JustePort (requires Mono) which allows you to stream mpeg4 lossless files to your Airport Express.
For all hobby cryptologists among you, this is the hidden RSA key used by Airport Express:
59dE8qLieItsH1WgjrcFRKj6eUWqi+bGLOX1HL3U3GhC/j0Qg90u3sG/1CUtwC
5vOYvfDmFI6oSFXi5ELabWJmT2dKHzBJKa3k9ok+8t9ucRqMd6 DZHJ2YCCLlDR
KSKv6kDqnw4UwPdpOMXziC/AMj3Z/lUVX1G7WSHCAWKf1zNS1eLvqr+boEjXuB
OitnZ/bDzPHrTOZz0Dew0uowxf/+sG+NCK3eQJVxqcaJ/vEHKIVd2M+5qL71yJ
Q+87X6oV3eaYvt3zWZYD6z5vYTcrtij2VZ9Zmni/UAaHqn9JdsBWLUEpVviYnh
imNVvYFZeCXg/IdTQ+x4IRdiXNv5hEew==
Exponent: AQAB