This is my first self-developed cryptographic puzzle. I hope it is neither too hard nor too easy for you to break, and that you enjoy it. Please do not only post the answer, but also your way towards it.
You are Alan Turing 2.0 - a British intelligence officer trying to break newly created codes from around the world.
Based on intelligence gained by turning a Zambian cipher clerk, you are right now listening in on a test run of a Zambian-Zimbabwian ciphered exchange, codenamed "Project Anaconda", using a newly developed cipher going by the cryptic name of "BFTIODFTTWKBCSC".
The cipher clerk delivered to you
- the name(s) of the cipher,
- the route used, so your technicians could listen in and report to you the text transmitted,
- that the cipher requires a key that the clerk does not get to see, but that to his knowledge only a single key has been agreed upon during a meeting by the three-star generals overseeing the whole operation,
- that his input terminal had 29 keys: the alphabet, the space, the apostroph and the enter key, and a mode switch to select "Encrypt" or "Decrypt", but neither Shift nor numeric keys.
- that most likely some standard phrases will be used in the test conversations.
No other useful information could be gained until now; the interrogator will report to you at once if he gains anything valuable.
The technicians reported that the line has gone live only after they tapped into it.
- Decipher the test messages.
- Determine the key(s) used.
- Reverse-engineer the algorithm.
- Decipher the algorithm name.
- If possible, determine the respective country of the correspondents A and B.
The test messages reported by your technicians until now were the following:
Good luck, Mr. Turing.