972Unsolved Historical Ciphers
Republished copy of Daniel Bourdeau’s Unsolved Historical Ciphers, released under CC BY 4.0. Text unchanged; hosted by JIC alongside its translations; not an official copy by the author · View the original ↗
672 2133 6210 2190 6219 637 2127
conte di Olivares

Madrid → Doge and Senate of Venice · numerical syllabic cipher, Italian · 26 October 1628

Alvise Mocenigo to the Doge, Madrid 1628

Doge Giovanni Cornaro
toDoge Giovanni Cornaro

Archivio di Stato di Venezia, IT ASVe 0045 010 Busta 30 f. 174; DECODE R1874. Catalogued as an undated ciphered letter from an unknown sender to an unknown recipient. It is a despatch of Alvise Mocenigo, Venetian ambassador in Spain, dated Madrid, 26 October 1628. The Venetian chancery’s complete decipherment of it is imaged in the same record; the text here is transcribed from that decipherment and checked against the cipher. It is calendared in CSP Venice 21 no. 515.

Daniel Bourdeau · posted · updated

Method: read from existing decipherment · Extent: complete

Summary. The 16 images of R1874 hold four things. The first is the despatch, clear paragraphs alternating with paragraphs in a numerical cipher (images 8951–8954). The second is a clerk’s decipherment of the whole letter, with paragraphs numbered 6 to 9 in the margin (8955–8959). The third is a second copy of the despatch, enciphered separately and dated “Madrid li 26 Ott:re 1628” (8960–8964). The last is the address leaf, followed by a deciphered page of the next despatch, of 29 October. The clear text names the sender and date: Spinola lodging with his son-in-law Leganés, the English beaten off La Rochelle, Monterrey at Genoa. So does the Calendar of State Papers, Venice, vol. 21, no. 515, whose clear opening is the same sentence. Its “italics deciphered” passage (Cottington’s journey to Madrid dropped after Buckingham’s death, Endymion Porter waiting for orders, Rubens negotiating a truce with the Dutch) is on the decipherment page 8958. The decipherment was checked against the cipher in two ways. The cipher’s paragraph mark 6499 splits it into the decipherment’s paragraphs 6 and 7 at a steady two letters per group. And the one run of groups that occurs three times, 672 2133 6210 2190 62x9 637 2127, falls where “conte di Olivares” falls, at 26, 71 and 92 per cent of the paragraph against 25, 70 and 91 per cent. The key, a syllabic nomenclator, was not rebuilt.

01 The record

The DECODE images are not in the public domain and may be published only with the archive’s permission, so none are reproduced here.

02 The cipher

The groups are numbers written as clusters. The looped sign that looks like b is the period’s 6, and the s-like sign is a 5, which DECODE’s transcription renders as “13” or “21”. Every group has the form 5 or 6, then an optional 1–4, then two digits. After the first digit only 0, 1, 2, 3, 4, 7, 8 and 9 occur. The two copies have about 2,245 groups of 355 kinds. The group 6499 marks the edges of the numbered paragraphs. Each group stands for about two letters of plaintext: paragraph 6 (“Et già si è publicato… di ogni gran Casa di Spagna”) has 386 groups for about 760 letters, and paragraph 7 (“Continuo io… in alcun tempo”) has 245 for about 445. That makes it a syllabic cipher or nomenclator, not a simple homophonic alphabet.

Recovering the key from the ciphertext alone failed. Letter-by-letter homophonic annealing against a Renaissance Italian model gave gibberish, although the same solver decrypts a synthetic Italian homophonic cipher of the same size without error. Treating whole prefix classes as nulls did not help either. A monotone alignment of the groups against the decipherment, seeded with the Olivares runs, settled into even two-letter splits and gave no usable values. Rebuilding the key would need a fresh, group-exact transcription and more anchors.

03 The decipherment

The two ciphered paragraphs checked against the cipher, from the decipherment (8955–8956):

[6] Et già si è publicato, che seguirà anco il Re alla giornata, persistendo l’Ecc.mo nelle prime risolutioni, che il Re ò abbracci le tregue, overo le faccia assignam.ti pronti, effettivi, et sufficienti per le imprese necessarie. Il Conte di Olivares ha desiderato con buone parole, et promesse condurlo à risolutione di ritornar in Fiandra; anco con qualche violente termine lo hà procurato, ma il Marchese constantem.te è stato ne’ primi propositi, nè hà potuto non ricever molti disgusti. Continuano quelli delli conti, che le sono dimandati, et quello che più lo affligge è haver dato sua figlia in moglie à Don Diego Messia, il quale è mantenuto dal Conte di Olivares nel posto di auttorità et gratia che haveva prima, se le diminuisse la speranza del titolo di Grande, et resta la figliola con minor fortuna di quella che senza il favore del Conte di Olivares poteva conseguire con il parentado di ogni gran Casa di Spagna.

[7] Continuo io nelli affari propri con molti soldati di S. M.tà, li quali si offerseno di nuovo al servitio della Ser.ma; alcuni sono officiali di molta esperienza, et con tanto maggior affetto le corrispondo; sono la maggior parte Napolitani de’ terzi reformati… et però certa cosa, che il Re non può render tutti contenti, et molti con ragione si vegono abbandonati, et altri senza le sodisfattioni de’ proprij crediti, et desperati di poter li conseguire in alcun tempo.

That is: it is given out that the King will go on campaign. Spinola holds to his first position, that the King must either accept the truce with the Dutch or give him ready and sufficient funds for the campaign. Olivares has tried fair words and harsher means to send him back to Flanders, and has failed. Spinola is also harried over his accounts, and grieved that he married his daughter to Diego Mesía, whom Olivares keeps in favour while holding back the grandeeship. Paragraph 7 reports Mocenigo’s recruiting of officers left unpaid by Philip IV, most of them Neapolitans from disbanded tercios, for the service of the Republic. Paragraphs 8 and 9 (8957–8959) cover Savoy’s campaign against Genoa over Oneglia and Ormea, Cottington’s cancelled journey, Rubens, Catalonia and Valencia, and Savoy’s bid for the government of Milan.

Grades: the decipherment is contemporary (H). The transcription above is a first pass from the scans. Two words are doubtful (M): “prime risolutioni” and “terzi reformati”.

04 What remains open

05 Sources

Notes, token files and solver scripts: targets/r1874/ in the repository.