T-52e cipher machine ==================== 1st problem ----------- We know everything (the internal key and the message key). If, moreover, the working of the machine T-52d is known, the message can be decrypted (you need to build or use a T52 simulator). 2nd problem ----------- We know nothing. The size of the message is about 3000 characters. Perhaps it is impossible to solve with standard computer equipment. 3rd problem ----------- We know the inner setting. 4th problem ----------- We have several messages "in-depth" but we know the inner setting. 5th problem ----------- We have several messages "in-depth", no extra help.