RC4/ADP encryption

[Matt25]

Hi all!

 

I am new to this forum, so I am not sure where to ask this but I figured this would be the best place!  I am a self proclaimed radio buff, and I am using a Motorola APX 6000 for work and recreational purposes.  I enjoy tinkering with things and recently I have begun looking into ADP, which is basically just RC4 in a glorified, proprietary form.   I would like to try to defeat the ADP cipher and recover the key that I created.  I have done some research, and I have found numerous RC4 decoding scripts/programs out there, but nothing that addresses specifically ADP.  Does anyone have any suggestions or experience with this?  I believe the best route is to use an SDR program to analyze the P25 audio stream, and then use the silent frames to recover the encrypted text.  Then, run the encrypted text through an RC4 decoder.  I look forward to any suggestions/advice!  Thanks in advance