Dorabella & D'Agapeyeff Ciphers - Solutions

Running Key and Cryptovariable Flowchart

 

The Running Key (6 segments, RK1 to RK6) begins in the bottom left corner of the circular diagram and flows clockwise. CV1 is derived from RK1, CV3 and CV4 from RK3 and RK4, CV6 from RK6. RK2 and RK5, however, are used directly as the Key which enciphers the Plaintext - but under the direction of CV2 and CV5, which together form the Message-Setting Keyphrase hidden within the Plaintext and controlling the expansion or stuttering of the Keytext. Additionally, the 1st 4 chars of the Plaintext are the message indicator.