T-52ca cipher machine ==================== 1st problem ----------- We know everything (the internal key and the message key). If, moreover, the working of the machine T-52ca 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 1400 characters. 3rd problem ----------- We know the beginning of the message. 4th problem ----------- We know the inner setting of the message. 5th problem ----------- We know the beginning and the inner setting of the message. 6th problem ----------- We have several messages in-depth.