II think bit message uses ECIES. I believe it's secure as long as you perform your key exchange ok and you're using a secure symmetric cryptography (I might be wrong). and I think ( but I don't know exactly what your program does) that you are using the same sort of ideas. You would probably be better off just implementing ECIES though.
 I don't think your OP explained your system in enough detail so it may have been misunderstood. Also bear in mind that I'm quite often wrong about stuff.