A Great Cipher Left Undeciphered by William Blencowe

An intercepted letter from the French foreign minister Torcy to French ministers sent to the peace talk at Geertruidenberg, dated 3 April 1710, is endorsed "M Blencow cannot decypher them."
Filed with it is another letter from Marshal Villars to the Abbé de Polignac, dated 1 June 1710. This also seems to be undeciphered.
I uploaded a new article "A Great Cipher Left Undeciphered by William Blencowe" describing BL Add MS 61575 including these. I also added references to these undeciphered pieces in "Unsolved Historical Ciphers"

Frederick I of Prussia's Transposition Cipher

I noticed three transposition ciphertexts (two of which are attributed to King Frederick I of Prussia) in DECODE. Two appeared to be non-decrypted, and I could solve them without much difficulty.
See my new article "Frederick I of Prussia's Transposition Cipher". I also listed them in "Unsolved Historical Ciphers."

Cardinal Richelieu Used a Porta-like Pairing Cipher?

Just as I wrote about the outage of the British Library's online services the other day, another important source, Internet Archive, went down about 10 October because of a DDoS attack. It's a sad realization that online services we take for grated may be attacked anytime and the attackers may have success sometimes.

Thankfully, it seems Internet Archive (at least archive.org that I need) appears to be working now.
Thus, I could access Wits Interpreter (1, 2), attributed to John Cotgrave (Wikipedia), which I learned printed Richelieu's cipher the other day. (Somehow, at that time, before the attack on Internet Archive, my search could not find this on Internet Archive.)
The cipher attributed to Richelieu (p.491) is a Porta-like pairing-based cipher. But the other ciphers following this all seem to be taken from Porta's book. So, a more reliable source is needed to confirm Richelieu really used this cipher. (After writing this, I noticed the section on Richelieu in "French Ciphers during the Reign of Louis XIII" already mentions Wits Interpreter from a secondary source.)

 

Some Ciphers from Henry IV's Time

When I was searching about the French ambassador Bordeaux in writing the post the other day, I ran across Dupuy 63. I added several ciphers from this volume:
ciphers of Seguier, Buzanval, and an informant to Henry IV (1601) in "French Ciphers during the Reign of Henry IV of France"; and
Francesco Guicciardini's Cipher (1597) in "Florentine Ciphers of Guicciardini (ca.1590-1593)".
It is notable that the three ciphers used in 1601 are of different nature. Buzanval (ambassador in The Hague) employed a symbol cipher with a seemingly large nomenclature in symbols. Seguier (ambassador to Venice) employed a symbol cipher, but his nomenclature was in Arabic figures with diacritics. The cipher of the king's informant employs Arabic figures both in the substitution table and the nomenclature, the character reminiscent of a cipher used with the Landgrave of Hesse-Cassel.

Two French Ciphers (ca.1643) in English Archives

French ciphers are sometimes found in English (and probably other) archives. I wrote about the Prince of Conde's cipher and one other the other day. Now, I added mention of two French ciphers (M. de Boisivon, Prince Harcourt) in "Ciphers Early in the Reign of Louis XIV". Although these were shared with English royalists, they are similar to contemporary French ciphers.

A Bundle of Ciphers of Lord Digby

It's almost a year since the British Library's computer system was disrupted by a cyber-attack (ransomware) in October 2023, but my links to BL materials do not work yet. It seems rebuilding the whole system to replace the previous patchwork of many legacy systems is taking time to fully recover their services (BL, detailed report as of March 2024 (pdf)). At least, I'm hopeful for future recovery because they say they have secure copies of all the digital collections and related metadata.

I was reminded of this when I saw volumes I studied some years ago in the DECODE database.
One of them is BL Add MS 72438 (a majority of no.8619-no.8645 in DECODE), which I found at https://www.bl.uk/manuscripts/FullDisplay.aspx?index=3&ref=Add_MS_72438 back in 2021, but the URL does not work now.
This volume contains "Cipher-keys and intercepted royalist correspondence from the papers of Georg Rudolph Weckherlin, government official, 1625-1647."
Georg Rudolph Weckherlin served Charles I in drafting, deciphering, and translating official correspondence, but after the Civil War broke out, he worked for the Parliament (DNB). In particular, he deciphered intercepted royalist letters (cf. n.36 in Philip Beeley, "Breaking the Code. John Wallis and the Politics of Concealment"). When Lord Digby's papers were captured after his defeat at Sherburn in October 1645, the cipher letters were delivered to Weckherlin (and a Mr. Frost), as I quoted in "Charles I's Ciphers".
F.1-f.24 are intercepted royalist letters (some are endorsed by or are in the hand of Weckherlin).
F.25-f.99 are cipher keys captured from Lord Digby's papers in October 1645. This includes the original of what I call "Third Cipher between Charles I and Henrietta-Maria (and Ministers) in Paris (Summer 1644-June 1645)" (f.67-68, DECODE R8687). F.100-101 (R8723) is its partial key (apparently by a codebreaker).
F.110-150 are ciphers used by Weckherlin while he was in the service of Charles I (ca. 1623-1641), partly in Latin and French.
I added two from Add MS 72438 which I believe are undeciphered in "Unsolved Historical Ciphers".

Another volume familiar to me is BL Add MS 18982 (DECODE (R8428-R8454)), which was at https://www.bl.uk/manuscripts/FullDisplay.aspx?index=0&ref=Add_MS_18982 when I found it before. It contains "Royalist correspondence, primarily addressed to Prince Rupert, 1645-1658."
Most of the undeciphered ciphertexts can be read by using already deciphered letters or with known keys. I added one from Add MS 18982 in "Unsolved Historical Ciphers".

Chinese Enciphered Code Analyzed in Arlington Hall

I wrote something about Chinese enciphered codes in "Chinese Cryptography: 1871-1945", but the materials available are relatively scanty. Now, I learned in Liza Mundy, Code Girls that a Chinese enciphered code was among those analyzed in Arlington Hall during WWII:
"There was a French code called Jellyfish, a Chinese enciphered code they called Jabberwocky, another they called Gryphon." (p.154 of the Japanese edition)
The source given is a weekly report (RG 0457, 9032 (A1), Box 1114, "Signal Security Agency Weekly Reports, Jan to Oct 1943", Weekly Report for Section B-III, July 9, 1943). I wonder whether the original materials are not preserved.

How about a Puzzle in Latin?

The additions reported yesterday include two unsolved ciphers (Bishop of Worcester, Serno Gilino). Both are in letters written in Latin (probably to Cardinal Wolsey) in the 1520s and both employ superscript digits (but they are clearly different ciphers).
For Worcester's cipher, I could identify symbols for single letters and some syllables. But when I apply these to undeciphered letters, I can only see some short fragments (e.g., "hu-n-c me-a-m", "no-n", "o-m-ni?-a") and the few long sequences of known symbols are incoherent to me (e.g., "...ri-s-tu-m-ri-po-r-ta-re-s-pe-re-n-t"). (I can see "riportare" but cannot think of words ending in "ristum" or beginning with "sperent".) For those versed in Latin, filling the blanks may be an interesting puzzle.
The relevant sections are now added in "Unsolved Historical Ciphers". See Ciphers during the Reign of Henry VIII for details.

An Early English Cipher Used by Cuthbert Tunstall (1517)

Cipher was already in routine use in the first years of the reign of Henry VIII. I now added one used by Cuthbert Tunstall in 1517 in "Earliest English Diplomatic Ciphers". It is used in the context of "the new treatie of Cambray". (In the treaty of Cambray signed on 11 March 1517, Francis I, Henry VIII, and the Emperor agreed on a crusade against the Turks (Sanderson Beck).)
I also added several specimens from 1526-1529 (Edward Lee, Bishop of Worcester, Francis Poynts, Sylvester Darius, Serno Gilino) in "Ciphers during the Reign of Henry VIII".