An unexpectedly fun read! A book that looks at history through a lens of cyphers, codes and decryption, starting with achaeological/linguistic problems (breaking the "code" of heiroglyphics and ancient Persian), running right through millennia of history, right up to (this book's) present day: the years leading up to World War II.
Another unexpected gift from this book: all the fascinating historical context the reader gets, simply because espionage, ciphers and codebreaking play such a role in so many important historical events. A wonderful bonus for history geeks. I only lament the fact that this book was published in 1939 and thus doesn't include the incredible stories of codes and codebreaking during and after WWII. This author would have done them great justice.
Notes:
1) Breaking the code of ancient Persian, which took up the consecutive lives of three brilliant code breakers, followed by the "breaking" of Egyptian hieroglyphics by French archaeologist Jean Francois Champollion around the same time. Deciphering an ancient, lost language is a type of cryptography as well, interestingly. "In a cryptological sense hieroglyphic was this a substitution cypher with suppression of frequencies and the introduction of a prodigious number of nulls."
2) "Now in most departments of human thought it is not permissible to make a hypothesis and then find facts to prop it up; but in cryptography this is frequently the only method that will work."
3) "A barmecide banquet"... nice phrase :)
4) "In short, when we begin to investigate the history of ciphers, we are digging in a graveyard whose limits we do not know and where there are headstones only for the failures. Decipherments that have changed the course of history (and they are not a few) are often recorded. The triumphs of encipherment, messages that got through without being read by interceptors I never mentioned--if for no other reason, because people who have used a cipher successfully wish to keep it a secret and use it again."
5) Different types of substitution cyphers with how to break them down.
6) Francis Bacon, (maybe) writing in cypher in the 1500, but a false solution to it.
7) Jargon, thievish argot as proto-codes in Europe
8) Frequency tables, used all over Europe by the 1500s; The Thithemius system: a cipher concealed by another message that makes sense in clear/plaintext, so it doesn't seem like a cypher. Also solves the vowel frequency problem; Suppression of frequencies technique.
9) Acrostics; Cardan's grille, a type of acrostic, although it requires a key in the form of an blockout grille.
10) Using a "[Francis] Bacon bilateral" as a secondary cipher, a trap, concealing a meaning two steps down.
11) See the Truth and Freedom movement in 1860s Russia, which eventually succeeded in assassinating Tsar Alexander II.
12) Vigenère and his invention of a type of private key cryptography the late 1500s, "the father of modern cryptography." His work was based on a simple seed word that acted as a key. His development was actually never used during his era, btut it was rediscovered in the cryptographic revival of the 19th century. Graf Gronsfeld, a German, combined it with the old Julius Caesar system, and produced a key made of numbers, making a streamlined version of Vigenère's method that was easier to use and much more difficult to break.
13) Antoine Rossignol, France's greatest cryptographer, during the era of Louis XIII to Louis XIV: So regarded that today "the device with which a lock is opened when the key is lost is still called in French a rossignol." "The doctrine he established--that a field cipher is acceptable if it delays decipherment of an order until the order can be executed--is still one of the basic principles of cryptography."
The Great Cipher of Louis XIV: unbroken for two centuries.
"The age of the cryptographic Giants under Louis XIV also produced its pygmies" hahaha :)
14) The rosicrucian cypher, or the pigpen cypher
15) The encrypted diary of Samuel Pepys, decrypted by John Smith in a tremendous act of decipherment, only to learn years later that a full complete key was included with another one of his works!
16) A Renaissance in cryptography in the 19th century driven in part by semaphore-based telegraph systems and then Morse code-based electric telegraph systems, as well as many political intrigues across Europe during these middle decades of the 1800s. Edgar Allan Poe gets hooked on cryptography.
17) apothegm: an aphorism
18) The Kasiski method: a technique invented by a German soldier, a major in the Prussian army, to break the Vigenère tableau encypherment technique.
19) Significant use of cryptography in the US civil war. Then by 1880 all European armies were using cryptography: it became totally necessary in the era of massed armies.
20) World War I turned out to be a disaster for many ciphers, mostly because two-step codes had to be repeated over and over (and over) again--up to five, ten, or even a dozen times--because even the loss of one letter makes entire messages unintelligible.
Lots of other incredible bunglings of cypher use in World War I: see for example the Russians forgetting which code book to use (!) and then having to send out messages in plaintext, allowing the Germans to know their movements and completely crush their army early on in the war.
There was so much cryptographic drama and intrigue in WW1, one could only wish that this book had been written several years later so that we could also hear this author's take on tremendously more drama in WWII.
21) More cypher bungling in WWI "New cipher not yet received, please repeat message in old cipher." The message was then repeated. Since the Allies had already broken the old cipher and thus now had parallel texts, this completely destroyed the new cipher too.
22) In the years following WWI, a number of machines appeared that were predecessors of the German encryption machines used in WWII.
Related books:
Crypto by Stephen Levy
Cryptonomicon by Neal Stephenson