Russian Diplomatic Ciphers in the 1860s

In 2016, I posted a specimen of a Russian diplomatic telegram in cipher at the time of the Alaska Purchase (1867), and called for information on the kind of cipher employed. Now, I was taught by Mikhail that Russian diplomatic ciphers in the 1860s are described in a book in Russian, which he kindly explained to me. It is a polyalphabetic cipher based on mixed alphabets, with a daily key consisting of 8 strips with 20 letters on each (i.e., the key is 160 letters long). This must have been among the best in the 1860s.
I updated the article: "Russian Diplomatic Cipher at the time of the Alaska Purchase (1867)". Now that the system is known, there remains a task of aligning the ciphertext and the plaintext and reconstructing the key. Any further information will be most welcome.

A Polyalphabetic Cipher of Mary, Queen of Scots

I added a polyalphabetic cipher used by Mary, Queen of Scots, in "Ciphers of Mary, Queen of Scots". (I learned of this cipher from Oliver Storz.) It was used in September 1568, a few months after Mary fled to England. This is the only polyalphabetic cipher used by Mary known to me.
Another interesting thing in this cipher is that the letter remained unsolved until the twentieth century, when it was solved in the French foreign ministry.

Cipher Letter of Francis II, Husband of Mary, Queen of Scots

I've been completing and uploading updates to some articles that accumulated while coauthoring the paper about Mary, Queen of Scots I reported the other day.
They include a cipher letter of Francis II, husband of Mary, Queen of Scots, addressed to the Bishop of Rennes (now included in "French ciphers during the Reigns of Charles IX and Henry III"). This is the first time I came across a cipher during the short reign of Francis II. (I'm sure there are more in the archives.)
Although it is not deciphered, it uses the same cipher that I reconstructed before from correspondence between the Bishop of Rennes and Catherine de Medicis.

More Ciphers/Letters Related to Mary, Queen of Scots

I reported my coauthored paper about the discovery of Mary Stuart's hitherto unknown letters the other day. I now uploaded "Ciphers of Mary, Queen of Scots". It lists ciphers and ciphertexts related to Mary (previously known ones for the most part). I still have some leads and hope to update it in near future.
Some ciphertexts are not accompanied with plaintext. I identified some of them with known plaintext. There still remain some ciphertext I could not identify, which I added in "Unsolved Historical Ciphers".

(18 February) I added a section for cipher letters related to Mary preserved in The British Library in "Ciphers Mary, Queen of Scots". I could identify most in my list with known plaintexts, and deciphered one by using the same key (Mary's letter to Norfolk in Cotton MS, Caligula C II, f.74).

50+ Letters of Mary, Queen of Scots (1578-1584), Discovered in French Archives

More than fifty letters of Mary, Queen of Scots, preserved in the French national library were found and deciphered by an international team of three cryptographers including me (George Lasry, Norbert Biermann, Satoshi Tomokiyo). The tragic life of Mary is well-known -- after three mariages, she fled to England, where she was held prisoner, and after years of captivity, she was executed on evidence of a deciphered letter for plotting against Queen Elizabeth. The letters discovered are entirely in cipher, with nothing to indicate who wrote them to whom and when. Codebreaking revealed that most (54) of the letters are letters written during 1578-1584 from Mary to Castelnau de La Mauvissière, French ambassador in England. Among them, more than 40 up to the middle of 1583 are hitherto unknown letters and are expected to provide new insights about Mary during her captivity in England.
The results were published in George Lasry, Norbert Biermann, Satoshi Tomokiyo (2023), "Deciphering Mary Stuart's Lost Letters from 1578-1584" in Cryptologia (Open Access) today, that is, 8 February, the anniversary of Mary's death.
I wrote an article in Japanese and a brief introduction in English. George talks on the discovery in a video.