Once I was particularly interested in ciphers of Lope de Soria, a Spanish ambassador in Genoa in the 1520s (see "Tracing the Origin of Vowel Indicators in Spanish Ciphers"). Now some of his cipher letters (1523) are in the DECODE database. They use two keys, printed in Galende Diaz (1992). I added reference to these letters in "Ciphers during the Reign of Emperor Charles V".
(The two recent additions to DECODE, R9531, R9530, are the cipher letters from which I reconstructed the keys in "Spanish Ciphers before Accession of King Ferdinand: 1470-1479" (Academia.edu).)
