Practice in Use of Ciphers in the Time of Catherine de Medici

I added a section "References to Cipher in the Correspondence of Catherine de Medici" in my article about French ciphers during the reigns of Charles IX and Henry III. It consists of excerpts of Catherine de Medici's letters mentioning a cipher. They are about instructions to use a cipher, delivery of a cipher, handling a cipher personally, forwarding of letters deciphered or to be deciphered, etc. They may be nothing new, but may allow a glimpse of practice in use of ciphers.