It is well-known that the Confederates used a polyalphabetic (Vigenere) cipher during the Civil War (see another article). The present article describes other codes and ciphers used by the Confederates.
Table of Contents:
Beauregard's Simple Substitution Cipher Etc.
Navy Dictionary Code
Bulloch's Cipher, Sinclair's Keyed Rotating Grille, and Morris' Letter Cipher
Dictionary Code of the Army and the Government
Secretary of War Seddon's Penchant for Caesar Cipher
Simple Polyalphabetic Cipher (Alternating Caesar Cipher)
Hieroglyphic Cipher for Confederate Conspirators (1863)
A Private Cipher (1863)
As of 18 March 1862, there were at least A.S. Johnston's cipher and Beauregard's cipher.
At least, Beauregard's was a very simple one as seen below.
Beauregard's cipher was so simple that one dispatch of Beauregard in cipher was read by the Federals on the day it was captured. The cipher was simply "putting the last half of the alphabet first, that is, substituting M for A, N for B, O for C, etc." (Brown p.212) (which seems to be what is known as "rot13" today).
The despatch was dated 9 April 1862 (right after the Battle of Shiloh, in which A.S. Johnston and Beauregard launched a surprise attack on Grant's Union army but Johnston was killed and Beauregard was forced to withdraw the next day, thus failing to block the Union advance into northern Mississippi (Wikipedia)), in which Beauregard appealed to S. Cooper (Wikipedia) at Richmond, Adjutant General of the Confederate Army and a close friend of President Jefferson Davis, to reinforce his army in order to counter the Federals under Buell to defend the Mississippi Valley.
The report of its interception is as follows (OR, vol.10, Part II, p.618, 108).
Although the Federals broke Beauregard's cipher, they did not have the wisdom to conceal the fact. The merit of breaking the enemy cipher would be nullified if the enemy knew the fact and changed the scheme (possibly to a more complex one). The deciphered telegram was advertised in the New York Herald of 21 April (ibid. p.440). (This may have been scooped by the newspaper rather than unwisely made public. Bates p.108 mention another instance of "premature publication in the newspapers of important military ovements" in February 1862.)
The article was reprinted in the Examiner, one of the leading Confederate newspapers (Encyclopedia Virginia). Cooper noticed it and, since he had sent the only copy to Robert E. Lee, then a military adviser to President Jefferson Davis, asked Lee to alert Beauregard (OR, vol.10, Part II, p.439-440). While Lee was still suspecting that the Federals had captured a plaintext version, he alerted Beauregard anyway.
Beauregard distributed his cipher (hopefully revised ones) even after this incident.
The last quotation above shows there was a War Department cipher besides Beauregard's. The "War Department cipher" may be the Vigenere cipher (see another article), which was mainly used at this time.
Even late in the war, Beauregard distributed "simple cipher" for use in telegrams that are important but are not so important to use "the diplomatic cipher."
The Confederate Navy used a dictionary code from a very early stage of the war.
In May 1861, Lieutenant (later Commander (OR Navy, Series II, vol.2, p.191)) James H. North was ordered to go to England to purchase an ironclad warship from the English or French government (OR Navy, Series II, vol.2, p.70, 107, 168).
Use of dictionary code can be seen in despatches between North and Mallory, Confederate Secretary of the Navy, in OR Navy, Series II, vol.2 as below. The dictionary used is Cobb, Lyman, The Reticule and Pocket Companion, or, Miniature Lexicon of the English Language (HathiTrust) (Wilson and Mckay p.307).
North to Mallory, September 1861 (p.88, 169)
Mallory to North, 28 June 1861 (quoted in a despatch of 20 November 1861; the original acknowledged by North on 16 August) (p.107, 88, 317)
North to Mallory, 7 June 1862 (p.206)
North to Mallory, 6 August 1862 (p.234)
North to Mallory, 30 August 1862 (p.254)
North to Mallory, 2 September 1862 (p.258)
Mallory to North, 20 February 1863 (p.364)
North to Mallory, 20 February 1863 (p.365)
North to Mallory, 11 April 1863 (p.400)
North to Mallory, 6 June 1863 (p.433)
Mallory told North on 13 December 1862 (unwisely in a cryptologic point of view) to use "your cipher only for important words" (p.308; acknowledged on 13 February 1863, p.360).
While the same dictionary was used throughout this period, several formats were used, as seen below.
North wasted more than a year because of lack of funds, which in turn was largely due to miscarriage of letters (OR Navy, Series II, vol.2, in passim, e,g., p.215, 229). Then, the British authorities made close inquiries into the destination and purpose of vessels being built in Britain and it became more and more probable that the vessel would be seized once it took to sea (OR Navy, Series II, vol.2, p.517, 502, 520, 581, 595, etc.). In the end, North could not continue to stay in Britain and the vessel being completed was sold to the Danish government in 1864 (OR Navy, Series II, vol.2, p.581, 587, 605, 651; Bulloch, vol.2, p.271).
Commander Semmes could not find Cobb' Miniature Lexicon in New Orleans and chose Reid's English Dictionary. The example given matches Alexander Reid, A Dictionary of the English language: containing the pronunciation, etymology, and explanation of all words authorized by eminent writers (1857 at Google; 1871 at HathiTrust).
The instructions to Lieutenant Maffitt, commanding CSS Florida, does not specify a dictionary. Letting commanders choose their own dictionaries is beneficial in avoiding using the same code throughout the navy.
Lieutenant Barney, commanding CSS Harriet Lane, chose a Webster.
An encoded message can be seen below.
The highest page number in the message is 262 and the highest line (or entry) number is 85. The column is either 1, 2, or 3. While there are many dictionaries bearing the name of Webster (The Online Books Page), 3 columns and 85 lines (assuming the latter indicates an unmanipulated line number directly) almost limits the candidates to the unabridged with its most condensed format (for example, Webster's Handy Dictionary (1877) has three columns but only 64 lines). One may rather rely on the relative location of the coded words in the dictionary (see another article for illustration of such a method), with the help of the context found in OR Navy or other sources.
Shortly before North, Captain (later Commander (OR Navy, Series II, vol.2, p.191 etc.)) James D. Bulloch (Wikipedia) was sent to England as an agent to purchase or build (wooden) steam propeller cruisers for use against the enemy's commerce (OR Navy, Series II, vol.2, p.64). Among others, he arranged for secret construction of wooden cruisers, CSS Florida and CSS Alabama (Wikipedia).
At first, it appears he was not given a cipher in view of his inability to go into details. (He also warned that an accurate account of his mission was reported in a New York newspaper.)
In October 1861, Bulloch took charge of a fast steamer, the Fingal, he bought to carry war supplies to the Confederate States (OR Navy, Series II, vol.2, p.95, 96; Wikipedia) and arrived at Savannah, Ga., in November. Although he intended to return to England with the Fingal loaded with cotton and rosin (OR Navy, Series II, vol.2, p.113), attempts to run the blockade by the US Navy failed. In January, he decided to go to England without the Fingal (OR Navy, Series II, vol.2, p.127, 132, 138-139).
When he returned to the Confederate States in November 1861, he appears to have been given a cipher.
Bulloch appears to have used the cipher in his despatch of 4 July 1862 and 7 January 1863 (OR Navy, Series II, vol.2, p.212, 331) but, finding it too tedious, he used it only sparingly. Mallory's despatch of 27 October 1862 to Bulloch is also marked "Sent in cipher" (OR Navy, Series II, vol.2, p.284).
According to Wilson and Mckay (p.42, p.307; I am yet to study their sources), Bulloch used Cobb's Miniature Lexicon also used by North.
"Bulloch's cipher" was also to be used by Captain Barron, who was to receive from Bulloch the two ironclad vessels being completed (designated 294 and 295, North Carolina and Mississippi). (These ships ended up being seized by the British authority and Barron stayed in Paris as a flag officer commanding Confederate State naval forces in Europe (Wikipedia; OR Navy, Series II., vol.2, p.507-509))
Bulloch, on his turn, decided to forgo the cipher and use a messenger.
Lieutenant George T. Sinclair was ordered in May 1862 to go to England to construct or purchase a clipper propeller for cruising purposes and to command it himself (OR Navy, Series II, vol.2, p.191, 228).
It is known that he used in his despatch of 8 August 1863 a keyed rotating grille (a kind of transposition cipher, treated in a separate article). This despatch appears to have been written on the advice of Mason to Sinclair, 20 July 1863 to warn against having the ship being built launched until there was a final decision in the Alexandra case in the British law court (OR Navy, Series II, vol.2, p.466). The propriety of the seizure of the Alexandra by the British authority in April 1863 was then pending in the court.
Despite utmost precaution, the Pampero, Sinclair's vessel being built in Glasgow, was detected and seized by the British authority (OR Navy, Series II, vol.2, p.566, 567, 575; 290 Foundation) and never served the Confederacy (Bulloch, vol.2, p.272 ff.).
In January 1864, Lieutenant Charles Manigault Morris was tasked with a cruise against the enemy's commerce and was provided with a cipher. (The following appears to be a fixed phrase and a similar wording is also seen in instructions to Lieutenant Campbell, commanding CSS Rappahannock, given this month (OR Navy, vol.2, p.819).)
When Lieutenant Morris, commanding CSS Florida (Wikipedia), used cipher in his undated letter to Mallory, the Secretary of the Navy appears to have had some trouble and told Morris to mark words with figures alternately to the left or right of the words. This suggests that the cipher consisted in letters, not figures. It also excludes the keyed rotating grille, in which word breaks do not make sense in ciphertext. It may have been a Vigenere used by the army and the government (see another article).
In October 1864, CSS Florida was illegally seized by the US navy in a Brazilian harbor while Morris was ashore. Morris reported his "hope" that the cipher etc. were destroyed.
On 15 April 1862, G.W. Randolph, Secretary of War at the time, sent a cipher to D.H. Hill, who was commanding at Yorktown. This may or may not be the same as the dictionary cipher arranged in this spring (see the next section).
Confederate president Jefferson Davis arranged a dictionary cipher with A.S. Johnston on 26 March 1862.
An actual letter in such a dictionary cipher, from J.E. Johnston to Robert E. Lee, dated 8 April 1862, is found at Civil War Day by Day. The way only some code numbers are accompanied by their decipherment suggests there was some problem in decoding this.
Johnston's despatch two days before this in response to Lee's telegram in cipher is in OR, vol.11, Part III, p.423.
J.E. Johnston was given "Revised edition abridged from N. Webster by W.G. Webster" by the President in the spring of 1862. (The Online Books Page lists something similar (HathiTrust), albeit not the exact edition.) They appear to have switched to Vigenere by May 1863 at the latest (see another article).
As late as February 1863, Seddon, Confederate Secretary of War since November 1862, thought of using the simplest Caesar cipher (OR, vol.14, p.763).
It seems the ridiculous proposal was not carried into effect and it appears the Vigenere cipher was introduced later in the month (see another article).
However, Seddon's frustration with cipher was so much that he proposed use of a simple monoalphabetic substitution cipher some months later.
Some media (Daily Alta California, 5 November 1863 "The Rebel Secret Cypher"; Sacramento Daily Union, 4 November 1863 "Copy of a Dispatch from Johnston to Pemberton"; Portrait Monthly of the New York Illustrated News (p.78, Internet Archive); etc.) report J.E. Johnston's secret message to Pemberton taken from the coat collar of a scout taken at Walnut Hills on 30 June 1863, which was deciphered by Michael Mason, Waterhouse's Chicago Battery. The episode is also included in Bates p.71.
This can be deciphered by simply alternately taking the third letter after or before the cipher letter, beginning afresh for every word (and correcting enciphering errors).
(Bates calls this "the 'Slater' code method" but if he refers to the commercial code by Slater, it is something different from the above (see another article)).
However, there is no plausible reason that Johnston, who used a Vigenere cipher with Pemberton in this period, should use a different scheme at this time. (Although the above may be seen as a Vigenere with a keyword "CY", it only replaces the question "why different scheme?" with "why different keyword?") This message is not found in Joseph E. Johnston, Narrative of Military Operations (Google), either. Still, the ciphertext is not a mere fabrication because Pemberton did send "a message of 28th", though Johnston says on 3 July that the message was destroyed by the messenger, who told Johnston of Pemberton's conditions (OR, vol.24, Part III, p.987).
On 21 December 1863, the postmaster of New York City intercepted a cipher letter addressed to "A. Keith, Esq., Halifax, N.S." and forwarded it to the Secretary of War at Washington. Keith had been previously reported to be in frequent communication with Confederate blockade-runners and other agents in the United States and thus his mails had been closely watched (Bates (1898) p.107).
After attempts were made in vain, it was sent to the telegram rooms, where cipher operators Tinker, Bates, and Chandler worked on it.
(Plum p.41, Bates (1898) p.108, and Bates (1907) p.73 all print different images from each other. The above is based on Plum's.)
Apparently, use of several different substitution alphabets including hieroglyphic symbols, ordinary letters, pigpen symbols, etc. frustrates simple frequency analysis. Still, a clue is found in the plaintext words "reaches you" and explicit word division would help. A hypothesis for the preceding two words "before this" was the breakthrough. Starting with these identified symbols, it took only four hours to decipher the whole.
The addressee was none other than J.P. Benjamin, Confederate Secretary of State (Wikipedia) and the signer J.H.C was a gunrunner J.H. Cammack and the message reveals a bold plan to hijack Atlantic liners for transport. Conspirators were arrested and arms and ammunitions were seized. (Bates p.75, 78)
Once the key was revealed this much, a second letter, from Cammack to Benjamin H. Hill, intercepted three days later could be readily read. It was about machine and paper for printing Confederate bonds. Soon the lithographer and the printer were arrested (Plum p.42).
Soon after the Confederate capital Richmond fell, the original key was found on 6 April 1865 in the office of J.P. Benjamin in Richmond (Bates p.77, 84).
A Confederate officer James Malbone, wounded at the Battle of Chancellorsville from 30 April to 6 May 1863, used a cipher he devised himself in his diary for 1863 and 1864. The cipher consists of symbols such as punctuation marks, dollar sign, etc. for the letters of the alphabet. He used cipher not to conceal any military information but to gossip about the wife of Jefferson Davis etc. (Saratogan Local News; AP; MailOnline)
The diary was deciphered by Kent D. Boklan in 2014 and published in Cryptologia.
The scan and transcription of the original diary can be found at New York State Division of Military and Naval Affairs: Military History.
William R. Plum (1882), The Military Telegraph During the Civil War in the United States, vol.1 (Google), vol.2 (Internet Archive) [unless specified, vol.1 is meant herein]
David Homer Bates (1907), Lincoln in the Telegraph Office: Recollections of the United States Military Telegraph Corps during the Civil War (simply "Bates" herein) (Internet Archive)
David Homer Bates (1898), "A Rebel Cipher Despatch", Harper's New Monthly Magazine Volume 97 June to November 1898, p.105-109 (Internet Archive)
James D. Bulloch (1883), The Secret Service of the Confederate States in Europe; or, How the Confederate Cruisers Were Equipped (Internet Archive: vol.1, vol.2)
Wilson, Walter E. and Gary L. Mckay (2012), James D. Bulloch: Secret Agent and Mastermind of the Confederate Navy (Google)
W.F. Friedman, "History of Cryptology" (pdf)
The war of the rebellion: a compilation of the official records of the Union and Confederate armies ("OR") [Series I is meant, unless otherwise specified] (Making of America, ehistory)
Official records of the Union and Confederate Navies in the War of the Rebellion ("OR Navy" herein) (Making of America, Western Illinois University)