Valence Cipher

Les Soldats Serpentins uses the Valence Cipher in all official communications. It is a type of substitution cipher in which each letter in the real-text is replaced by a letter some fixed number of positions elsewhere on the alphabet. Each proceeding word would have the key shift change based on the length of the preceding word. Punctuation and capitalization of proper nouns was eliminated to reduce the chance of the cipher being broken.  The initial key to the cipher is cleverly hidden among the message. Members of Les Soldats Serpentins were issued a rotating cipher disk so they could more easily encode and decode messages.

All official communications would have a five digit code in the lower left hand side of the communication. These numbers would be added and their sums reduced until the result was a single digit number. For example 85172 would be 8+5+1+7+2 = 23, then 2+3 = 5. This gives the initial key shift value. If the original number was even the shift would be to the left, if the number was odd, the shift would be to the right. 85172 in this instance, results in a left shift.

Using the above example 85172 results in a left shift of 5, as such, F would be replaced by A, G would become B, and so on. The numeric length of the previous word would determines the new key length of the following word. For example Jqrnsfyj becomes Eliminate. Eliminate consists of nine letters, so the new key length for the next word is nine. This method continues for the length of the message. 

A message written as: 14676 znk wdujhw oy okpkuvgt kmttqmz lsptpuhal qrv

Decodes to: the target is minister cellier eliminate him

A Valence rotating cipher disk can be used to encrypt or decrypt the code.