US Navy Secret Code of 1887 Used at the Time of the Spanish-American War (1898)

Telegraph codes of the US War Department and States Department in the late 19th century are described in other articles. The Navy Secret Code of 1887 is discussed by participants at a German cryptology blog (Klausis Krypto Kolumne) and is briefly described below.

It is described by William F. Friedman, who was given permission to consult the actual code books preserved in Navy Security archives (Friedman Lectures on Cryptology (pdf) p.93-94, 101-102).

The U.S. Navy Secret Code (1887)

The code is titled The U.S. Navy Secret Code and was used from December 1887. It was accompanied by The Book of Key Words and General Geographical Tables.

When encoding a message with this system, the first step is to use the basic code book (The U.S. Navy Secret Code) to encode the message with 6-digit figures. Then, the sequence of 6-digit figures are regrouped into 5-digit groups, which are converted to "outlandish" code words with the cipher book (presumably, The Book of Key Words). Use of such "outlandish" words as code words was a common practice in telegraphy at the time (see another article).

Theodore Roosevelt to Commodore Dewey, 26 February 1898

Friedman demonstrates the decoding process of an actual message.

On 15 February 1898, US Battleship Maine was blown up in Havana, Cuba (Wikipedia). Theodore Roosevelt, Assistant Secretary of the Navy (and future president), acted for preparing the navy during the temporary absence of the Secretary of the Navy and sent the following telegram on 26 February 1898 to Admiral Dewey at Hong Kong. It was two months before the declaration of war that began the Spanish-American War.

Theodore Roosevelt to George Dewey, 26 February 1898
WASSERREIF PAUSATURA BADANADOS CENTENNIAL TITUBANDI LOSCHBANK VOVETE OFFENSADO CRAQUIEZ PICARAZADO NUMERATURA SPOILABLE APPILANTI DEPUGNERE DEMIDEVIL MONOSILABO ATOCHARON TACHONASEN ALIENATOTE CRENCHA SPARRWERKE
(This reflects two corrections made by Friedman.)

To read the telegram, first, the "cipher book" is used to translate these outlandish words into 5-digit figures.

WASSERREIF99055
PAUSATURA62399
BADANADOS11005
CENTENNIAL16820
TITUBANDI90000
LOSCHBANK52390
VOVETE98242
OFFENSADO59841
CRAQUIEZ21992
PICARAZADO64004
NUMERATURA58639
SPOILABLE83607
APPILANTI07319
DEPUGNERE25545
DEMIDEVIL24980
MONOSILABO56346
ATOCHARON09599
TACHONASEN87782
ALIENATOTE04665
CRENCHA22099
SPARRWERKE83000

Since the basic code book employs a 6-digit system, the sequence of 5-digit figures thus obtained is regrouped into 6-digit figures.

(sequence of 5-digit figures)
99055 62399 11005 16820 90000 52390 98242 59841 21992 64004 58639 83607 07319 25545 24980 56346 09599 87782 04665 22099 83000
(sequence of 6-digit figures)
990556 239911 005168 209000 052390  982425 984121 992640 045863 983607  073192 554524 980563 460959 987782 046652 209983 000

Now, the basic code book can be used to recover the plaintext.

990556SECRET AND CONFIDENTIAL
239911ORDER THE SQUADRON
005168EXCEPT
209000THE MONOCACY
052390TO HONGKONG, CHINA
982425KEEP FULL OF COAL
984121IN THE EVENT OF
992640DECLARATION OF WAR
045863SPAIN
983607IT WILL BE YOUR DUTY TO SEE THAT
073192THE SPANISH SQUADRON
554524DOES NOT LEAVE
980563ASIATIC COAST
460959AND THEN
987782OFFENSIVE OPERATION(S)
046652IN PHILIPPINE ISLANDS
209983KEEP OLYMPIA UNTIL FURTHER ORDERS

Similar Codebooks: Commercial Code and War Department Code

Representing a word into a number and then regrouping the sequence of digits to find a code word for transmission is used in a commercial code book well-known as Slater's Code (see another article). In one of its many superencipherment schemes ("Example IV") described in its introduction, words "The Queen ..." are converted to 5-digit figures (22313 18095 ...), which are then regrouped into 4-digit figures (2213 3180 9512 ...), by which code words for transmission (begged bulging freak ...) are found.

Slater's Code, including the examples in the introduction, was used as a basis for a telegraph code of the War Department in 1885 with only a minor adaptation (see another article).

A First Step to Reconstruct the Code

By sorting the lists in the above, we may reconstruct a very small portion of the code.

The basic code book:

(basic vocabulary)
005168EXCEPT
045863SPAIN
(location)
046652IN PHILIPPINE ISLANDS
(destination)
052390TO HONGKONG, CHINA
(expressions about fleet)
073192THE SPANISH SQUADRON
209000THE MONOCACY
209983KEEP OLYMPIA UNTIL FURTHER ORDERS
239911ORDER THE SQUADRON
(common phrases)
460959AND THEN
554524DOES NOT LEAVE
(expressions about military operations)
980563ASIATIC COAST
982425KEEP FULL OF COAL
983607IT WILL BE YOUR DUTY TO SEE THAT
984121IN THE EVENT OF
987782OFFENSIVE OPERATION(S)
990556SECRET AND CONFIDENTIAL
992640DECLARATION OF WAR

Considering that Slater's Code had 25000 entries, the size typical at the time, a million entries seems too large. There may have been many blanks.

The cipher book:

ALIENATOTE04665
APPILANTI07319
ATOCHARON09599
BADANADOS11005
CENTENNIAL16820
CRAQUIEZ21992
CRENCHA22099
DEMIDEVIL24980
DEPUGNERE25545
LOSCHBANK52390
MONOSILABO56346
NUMERATURA58639
OFFENSADO59841
PAUSATURA62399
PICARAZADO64004
SPARRWERKE83000
SPOILABLE83607
TACHONASEN87782
TITUBANDI90000
VOVETE98242
WASSERREIF99055

Commodore Dewey to Secretary Long, 1 May 1898

The telegram presented at Klausis Krypto Kolumne is the one sent from Commodore Dewey to Secretary Long.

(There was no trans-pacific submarine cable until the next century (Wikipedia). Dewey's report was delivered by revenue cutter McCulloch (Wikipedia) on 7 May to the US consul at Hong Kong (Kahn p.254), who forwarded it by cable via Europe.)

(Red color indicates repetition. Considering the regrouping, the repetition of "INCLEMENTE" may be a mere coincidence. Slash (/) is to mark groups of six code words, which correspond to five 6-digit groups in the basic code book.)
CRAQUEREZ REFRENANS VIJFVOETIG IMPAZZAVA PRENSABERE INTRUSIVE / REGENBUI EDIFIERS RETAPIEZ DECRUSAMES IMPAVIDEZ RIBOTIEZ / GOLDKRAUT RIONORAI SANSCRITO FLEMINGS BROMIDO SUPERFICIE / GALEFFAVA BOWLINE ALDERMEN ENTOILERAI WATERTHIEF DEFENSABIS / GIFTMORD AGOURADA HONEYGUIDE EXCALDABOR VORHASCHEN CONLUCETUR / GAMETRIA PEZADA BRANDAL SAUKNOTEN DEARTUAREM SILBATO / ALEXICACIO EDITASEN SUSPIRARAS ECLUSIEZ UNTERHEFE APPACIO / GROWLS HEXAPLA INCLEMENTE TURLERIN UNTERHEBEN ULTIMAMUS / GLADIATOR SQUILLANDO ABHORREBAM GENIAZO SUMPTER GEFLOGEN / GAMETRIA PEZADA BRANDBLASE CRISUELA ASEMEJAR ABRIPIEBAR / ADHIBEBIT STIRRING FORTNIGHT SIGNIFICAR APICULATED BRICOLAMES / CRASENZA OMBRAGE SCHRATTEL ASOMBRAR SCHULPROBE MUGIOLINO /
ARGEMONE WEIBERRATH HAMAXANDOS SETULOSE MENGSPATH BLUTNUSS / ASCHUCHARON ECUMENICAL KNELBRUSH LAVATORIO ROSOBODA ACCULATO INCLEMENTE / MORINGA TODESBILD TRUNCARDES

The following lists the code groups sorted in alphabetical order.

ABHORREBAM
ABRIPIEBAR
ACCULATO
ADHIBEBIT
AGOURADA
ALDERMEN
ALEXICACIO
APICULATED
APPACIO
ARGEMONE
ASCHUCHARON
ASEMEJAR
ASOMBRAR
BLUTNUSS
BOWLINE
BRANDAL
BRANDBLASE
BRICOLAMES
BROMIDO
CONLUCETUR
CRAQUEREZ
CRASENZA
CRISUELA
DEARTUAREM
DECRUSAMES
DEFENSABIS
ECLUSIEZ
ECUMENICAL
EDIFIERS
EDITASEN
ENTOILERAI
EXCALDABOR
FLEMINGS
FORTNIGHT
GALEFFAVA
GAMETRIA
GAMETRIA
GEFLOGEN
GENIAZO
GIFTMORD
GLADIATOR
GOLDKRAUT
GROWLS
HAMAXANDOS
HEXAPLA
HONEYGUIDE
IMPAVIDEZ
IMPAZZAVA
INCLEMENTE
INCLEMENTE
INTRUSIVE
LAVATORIO
MENGSPATH
MORINGA
MUGIOLINO
OMBRAGE
PEZADA
PEZADA
PRENSABERE
REFRENANS
REGENBUI
RETAPIEZ
RIBOTIEZ
RIONORAI
ROSOBODA
SANSCRITO
SAUKNOTEN
SCHRATTEL
SCHULPROBE
SETULOSE
SIGNIFICAR
SILBATO
SQUILLANDO
STIRRING
SUMPTER
SUPERFICIE
SUSPIRARAS
TODESBILD
TRUNCARDES
TURLERIN
ULTIMAMUS
UNTERHEBEN
UNTERHEFE
VIJFVOETIG
VORHASCHEN
WATERTHIEF
WEIBERRATH

This message is presented in David Kahn, The Codebreakers, p.254. This is a report of the Battle of Manila Bay on 1 May 1898, in which Commodore Dewey destroyed the Spanish Pacific squadron (Wikipedia). The plaintext begins as follows.

Squadron arrived at Manila at daybreak this morning. Immediately engaged the enemy and destroyed the following Spanish vessels: Reina Cristina, Castillia, Don Antonio de Biloa, Don Juan de Austria, Isla de Luzon, Isla de Cuba, ....

Further Potential Sources

Richard W. Peuser, "Documenting United States Naval Activities During the Spanish-American War", Prologue, National Archives. In particular, "Record Group 45" is the source used by David Kahn, who says there are other code message with their plaintexts and reproduces one (p.1019, 253).

According to History of Communications-Electronics in the United States Navy by Captain Linwood S. Howeth, USN (Retired), 1963, pp.289-296 (online), there was also a 1908 edition. As of World War I, both the 1887 and 1908 editions were considered to have been compromised but the latter was used in a limited way.



©2015 S.Tomokiyo
First posted on 21 November 2017. Last modified on 30 December 2017.
Cryptiana: Articles on Historical Cryptography
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