“The Numerical-Astrological Ciphers In The Third Book Of Trithemius’s Steganographia”, 1998-10 (; backlinks):
I solved both Trithemius’s cipher [in Steganographia] and Ernest 1676 encrypted solution in 1993 and published a monograph on the subject in 1996 [as did 1998 independently].
In addition to drawing on my previous research, the following article includes several new observations and references, especially with regard to the chronology of the work, additional manuscript copies of the Steganographia, and the position of the 3rd Book within Trithemius’s complete cryptological oeuvre.
[Keywords: Johannes Trithemius, Wolfgang Ernst Heidel, Steganographia, Polygraphia, numerical ciphers, astrological ciphers]