Codebreaking: A Practical Guide

Have you ever stumbled upon something and felt like, I don't know, like it was whispering a secret, maybe an old journal up in the attic, or a weird symbol carved on some furniture at a flea market. Yea, even like a cryptic message on a tombstone.

Absolutely, that feeling that urged to figure it out. It taps into something really fundamental, doesn't it our drive to understand, to solve puzzles. It's just satisfying.

It really is seeking patterns, finding meaning where others just see well junk.

Maybe exactly, And that's exactly.

What we're diving into today, the world of code breaking. It's fascinating stuff. Is this whole deep dive actually came from one of you, a listener who's really intrigued by hidden messages just like us. Ah, excellent, And our main guide for this is going to be the book Code Breaking, A Practical Guide by Ilonka Dunnin and Close schmah.

Oh, that's a great choice, really accessible dun In and Schmid. They know their stuff, but they make it engaging, not too dry.

Totally agree. I'm here, you know, always curious about intriguing subjects.

And I'm here happy to delve into the history and the actual practice of encryption. It's a field I find endlessly fascinating.

Great, so between us, hopefully we can unravel some of this for you. Let's give it a shot now. Our goal today. Look, we're not going to turn you into a master code breaker in what the next.

Hour slight juckle, probably.

Not no, but we want to give you a really solid grasp of the basic ideas. You know, what a codes? What are ciphers? Look at different types?

You share some really cool stories, success stories, failures sometimes too, just to give you a real taste of it exactly.

We want you to walk away appreciating the cleverness involved both in making the codes and breaking them.

And maybe just maybe inspire you to try a simple puzzle yourself. It can be quite addictive, definitely, and.

We should mention the authors again, Elanka Dunn and Cheese, known for working on huge unsolved codes like cryptos.

Right, the CIA sculpture one.

Yeah and she pops up in Dan Brown's the Last Symbol. And Klaus Schmah He's written loads, very respective and apparently quite entertaining in his presentations.

They're a good team for this kind of practical guide deep knowledge, but they make it approachable.

Okay, let's get started. Then, At its most basic level, what is encryption? Why do we even bother hiding messages?

Well, fundamentally, it's about secrecy, concealing the meaning of a message so only the intended recipient can actually understand it.

Privacy security exactly.

Keeping information safe from prying eyes, whether that's military secrets, diplomatic messages, or you know, just a private note.

Got it now. The book draws a distinction right away between two main things, cipher's and codes. What's the difference there.

Right, that's a key distinction. So think of it like this. Ciphers generally work on the letters of a message. You're substituting or rearranging individual letters according.

To some rule, okay, letter by letter, yeah.

Whereas codes they work on whole words or phrases. You have a pre agreed list like a dictionary, where specific words or phrases are replaced by a symbol or another.

Word, like a secret dictionary.

Almost exactly. And the book uses the analogy that codebooks can get really huge and unwieldy. If you want to cover lots of words, I.

Can imagine you'd need a massive book for every possible thing you might want.

To say precisely, Cipher's because they work on the letters. The building blocks are often more flexible, more compact. You just need the method.

The key makes sense, and the book mainly focuses on Cypher's right.

Yes, for the most part. Codes and related systems like nomenclators come up later, but the bulk is on cipher techniques.

Okay, so Cipher's it is mostly. Now, imagine you find this jumbled mess of letters. Where do you even start? What's the first thing a codebreaker does well.

One of the absolute fundamental techniques, and the book introduces it early is frequency analysis.

Ah, I've heard of that.

Counting letters basically, yes, you literally count how many times each different letter or symbol appears in the ciphertext the encrypted message.

Why what does that tell you?

Because languages have characteristic frequencies. In English, for example, E is by far the most common letter, then TAOI, N, and so on. So the idea is, even when the letters are scrambled or substituted, those underlying frequencies might still show through in the ciphertext. If one symbol appears way more often than others, it might be the encrypted E exactly. It's an educated guess a starting point. The book gives

Okay, so frequency analysis is your foot in the door looking for that disguised E.

Makes sense, It's a cornerstone. Doesn't always work, especially with more complex ciphers, but for many classical ones it's vital.

Right now, the book dies into a whole bunch of different cipher types. This is where it gets really interesting. Let's start with substitution ciphers. What's the basic idea.

Substitution is pretty much what it sounds like. You substitute each letter in your original message the plaintext, with a different letter or symbol based on a fixed system.

And the simplest version is just swapping one letter for another consistently, like every A becomes a Q, every B becomes an X.

Precisely, that's a simple substitution cipher, or sometimes called a mono alphabetic cipher one to one mapping. The book mentions a fun example from Klaus's blog Oh Yeah, a challenge cipher from twenty fifteen. Someone cracked it really quickly using frequency analysis and figuring out The keyword used to create the substitution alphabet was Gordon Young.

Wow, so the keyword determine the whole swap. M cool. What about the Caesar cipher. That's the famous one, right you and I've heard of that.

Yeah. The Caesar cipher is a type of simple substitution, but a very specific one. You just shift every letter a fixed number of places down the alphabet, like three places.

So A becomes dB becomes.

E exactly, wrap around at the end, so x becomes a, hy becomes b, z becomes c if it's a shift of three. Super simple. The book mentions Herbert Yardley, an early US codebreaker, use it for his first ciphergram.

Huh. Even the pros started.

Simple, they did. And there's that funny newspaper example do Lo, which decrypts with a shift, but the result is still partly gibberish.

Right April third, if you work here, it doesn't always pay perfect sense exactly.

And the mug the inscription that decrypts to National Security Agency.

With the typo. That's brilliant. Even spies make.

Typos, apparently, so shows it happened.

Okay, so simple substitution Caesar shifts, but they can get trickier. Right, What about homophonic ciphers. It sounds complicated.

They are a step up. Homophonic means same sound, but here it means multiple Ciphertext symbols can stand for the same plaintext letter.

Wait, so E might be represented by a seven, or a percent or.

A k precisely. Especially for common letters like E or T, you give them multiple substitutes. The goal is to flatten out those telltale frequency counts we just talked about.

Ah, so it makes frequency analysis much harder, much harder.

If E can be five different things, Just counting symbols doesn't tell you as much.

So how do you break those? Well?

Today computers are the best bet, using techniques like hill climbing, basically trying small changes to a possible key and seeing if the output looks more like English.

Okay, computer power, but manually.

The book gives a geocaching example. If you have spaces between words, that helps enormously. You can still do some frequency counts on the symbols. Guess short words like at or the he, look for common pairs like thh. It's painstaking work.

Geocaching makes sense they'd use tricky codes, okay. Another one that sounds weird.

The pig pen cipher chuckles slightly. Yeah, the name's descriptive. It's geometric cipher. You use grids like a tic tac toe board, maybe with dots in some sections. Each letter is replaced by the shape of the pen or grids segment it sits in.

Okay, so shapes instead of letters, right.

The book shows that tombstone from seventeen ninety six. It uses pigpen and reads dia. Another typo should be deck.

They were having trouble with spelling back then. Even in code.

Seems like it. And there's the pirate Olivier Lavaser's cryptogram from the seventeen thirties. Many think of his pig pen possibly cracked using frequency analysis on the symbols.

Pirate treasure maps with geometric codes. Yeah, fantastic. Okay. Playfair cipher sounds more serious.

It is. Playfair is a step up again. It's a digraph cipher, meaning it encrypts letters in pairs, not one by one. It uses a five x five grid, usually filled with a keyword first than the rest of the alphabet, combining I and J. Then there are rules based on whether the pair of letters are in the same row, same column or form a rectangle in the grid.

Wow, Okay, that sounds much more involved rules and a grid based.

On a keyword, it is much harder to break than simple substitution. The book mentions Robert Thelis's nineteen forty eight cryptogram. Modern breaks often involve computers trying lots of potential keywords to generate the grid. The book gives an example using black and beauty as keywords in the analysis.

So computers crunching keywords, got it? And general digraph substitution is at just any pair for pair swap.

Pretty much Playfair has its specific rid rules. General digraph substitution just means swapping pairs of letters for other pairs, but without those specific Playfair constraints, potentially many more possibilities. Klaus apparently set a challenge on his blog with one of those.

Okay, So substitution covers a lot, from simple shifts to complex paired letters. But the book also talks about transposition ciphers. How are they different?

Totally different approach. Substitution changes what the letters are. Transposition just changes.

Their order, like shuffling a deck of cards.

Exactly all the original letters are still there, just jumbled up according to a specific secret rule or pattern.

So it's like a complex anagram. The book mentions complete columnar transposition. How's that work?

Right? You take your message, write it out in a grid, say row by row. The number of columns is usually based on the length of a keyword. Okay, then you read the letters out column by column to get the ciphertext. But here's the key The order you read the columns in depends on the alphabetical order of the letters in your keyword.

Ah, so the keyword tells you the shuffled column order. Clever. The book uses Swiss cheesecake as an example.

Yeah. With the keyword table, it lays it out clearly. A is the first letter and table. So you read the A column first, then the B column and so on.

Got it? And incomplete Columner transposition is that just when the grid isn't.

Full exactly, if your message length doesn't perfectly divide by the keyword length, the last row won't be full. The book mentions an IRA cryptogram one hundred and thirteen letters. That's a prime number.

Oh right, so it can't make a need rectangle except one by one thirteen or one thirteen by one.

Correct. Which makes it trickier. Breaking these sometimes involves multiple anagramming, basically trying to rearrange the columns computationally until fragments of words start appearing.

Prime numbers, making life difficult for code breakers. Yeah, and then there's double column to transposition. Do it twice pretty much?

Yeah, You transpose it once with one keyword, then you take that jumbled text and transpose it again with a second keyword. Makes it much much harder. About the book mentions Marzie's report on ciphers using keywords from an Italian poem. They were tough nuts to crack until Arman Krauss figured something out.

What was that?

He realized the first and last blocks of letters in the messages weren't part of the main text, but were like indicators metadata. Once you remove those, the double transposition underneath became solvable.

Wow. Sometimes the clue isn't even in the main message. Fascinating. Okay, one more transposition type. The turning grill sounds very physical.

It is. It uses a stencil like a piece of card stock with holes cut in it. That's the grill. You lay it over a grid, write letters through the holes, then you turn the grill. Usually ninety degrees, write more letters in the newly exposed spots. Repeat for four.

Turns, so the grill reveals different spots with each turn exactly.

Then the cipher text is just reading the whole grid filled with letters. The book has a Christmas card example, and there's a great historical case in eighteenth century German. One solved manually because the person writing the message was a bit sloppy didn't place the letters precisely in the openings.

Huh. Human error strikes again even with gadgets. Okay, substitution changes letters, transposition shovels them. What about poly alphabetic ciphers?

Poly alphabetic this is where things get significantly more secure classically speeding. Instead of one substitution alphabet, you use multiple.

Alphabets a multiple alphabets.

Usually controlled by a qword. Each letter of the keyword tells you which substitution alphabet to use for the corresponding letter of the plaintext. So the same plaintext letter, say E, could be encrypted to X one time and then K the next time it appears, depending on the keyword letter.

Okay, so that really messes up frequency analysis.

Right absolutely, because E doesn't always encrypted the same thing. The most famous poly alphabetic cipher is the Visienner cipher.

Wait, I heard of that one too.

The book explains the basics. Ngth really depends on the keyword length. Longer more random keywords make it much stronger, and the ultimate version is the one time pad. If your keyword is truly random, never repeats, and is as long as the message itself, theoretically unbreakable the gold standard.

Wow and cryptos. The first two parts use these polyalphabetic types.

That's right, K one and K two. The solved sections of the cryptos sculpture were polyolphabetic. K one use the keyword cryptos. K two use abscissa real world high profile examples cryptos.

Again, that thing is everywhere in code breaking. Okay, we've hit cipher's hard letters letters, letters, but you mentioned codes earlier. Working on words and nomenclators. What are they?

Nomenclators were historically super important. Think of them as a hybrid system. Hybrid how so they combined a codebook part lists of common or important words, names, maybe places with their secret code symbols, with a cipher part.

Oh so code for common stuff, cipher for everything.

Else exactly, Maybe a simple substitution alphabet to spell out unusual words or names not in the code list, or just to add another layer. Before maybe the nineteenth century, if you found a secret diplomatic message, chances were high it was a nomenclator.

The standard for a long time. Then why did they fall out of favor?

Well, partly because more complex mathematical ciphers became better understood, and then, especially with cipher machines like Enigma machines could handle complex polyophabetic stuff way faster and more securely. Right technology advanced, plus nomenclators had weaknesses. If someone captured the codebook, you were sunk. Or if codebreakers found a crib a known piece of plaintext within the message that could help

History turning on a broken code. Okay, and dictionary codes and book ciphers are they related?

Yeah, there's specific types of codes that use well. Book says the key Dictionary codes use a specific dictionary. The code might be like page one, twenty three, word five.

You need the exact same dictionary edition.

Absolutely crucial. MI eight, a US code breaking unit, broke one by figuring out which dictionary was being used. Book ciphers are similar, but often point to individual letters within a specific book, like page fifty, line ten, letter three.

Again, gotta find the book.

Exactly, Stephen Machis. Finding Nicholas Trist's Key Book to the British Nation was a huge breakthrough, and that Hindu conspiracy code cracked when a blog reader tracked down the right Noah Webster eighteen fifty seven dictionary. Amazing detective work.

Incredible finding the right book in a million Okay, So that covers a lot of the classical ground. But things didn't stop there. What about beyond classical methods. Machines come first.

Enigma Enigma is the big one.

Yeah.

Electro mechanical machines like Enigma were a massive leap the use rotors wires creating an incredibly complex, constantly changing polyolphabetic cipher for every single letter.

The WWII German.

Machine famously used by them, Yes, okay, and breaking it was a monumental effort. The polls did crucial early work than the French British at Bletchley Park touring and his team.

The Imitation game story a.

Big part of it. Yes, and Elizabeth Friedman and the US also worked on Enigma variants. The book mentions recent successes too, like the M four project breaking original Navy messages and ongoing work on others.

Just amazing the sheer brain power involved. What about encrypting voice?

That sounds different, very different technical challenge, especially early on with analog signals. Early voice scramblers weren't always that secure.

So how did they manage well?

One method the book touches on is code talking using obscure languages.

Like the Navajo code talkers exactly.

The most famous example using the Navajo language as the basis for a code that Japanese couldn't break in WWII. It's a human form of encryption, incredibly effective.

Using language itself as the lock. Brilliant. And lastly here staganography hiding the message itself right.

Staganography isn't about making the message unreadable, It's about hiding the fact that there even is a secret message.

How invisible ink.

That's a classic example. Yeah, sympathetic ink right between the lines, but it can be more subtle. The book mentions Elonka Dunnan finding a hidden message on the Friedman's tombstone, on.

Their tombstone, William and Elizabeth Friedman.

The codebreakers, the very same, a fitting secret tribute and way back. Trithemiis's Staganographia book from the fifteen hundreds looked like magic but actually contained hidden text revealed centuries later by frequency analysis.

Hiding in plain sight. So machines voice hidden messages. But computers must have changed everything again.

Right, oh, completely. The role of computers is immense techniques like hill climbing simulated a kneeling. These are out rhythms where the computer makes guesses, evaluates how good the result looks like, how much it resembles English, adjusts and tries again, thousands millions of times a second, So tasks.

That were impossible manually become.

Feasible, absolutely breaking complex classical ciphers like homophonic visionnaire, columber transposition, even making inroads into things like the Zodiac killer ciphers. Computers when in revolutionary they do the heavy.

Lifting, the ultimate code breaking tool. Now. Yeah, but even with computers, some things remain mysteries. The book mentions unsolved mysteries, cryptos K four has to be top of the list.

Still unsolved. Yes, K four, the last part of the crypto sculpture remains stubbornly unbroken, despite clees from the sculptor himself. It's probably the most famous active puzzle. The book mentions others the Beal ciphers supposedly leading to buried treasure, the Somerton Man cryptogram found in Australia, the Action Line cryptogram. Puzzles that continue to baffle and intrigue.

It's kind of cool that some secrets hold out, isn't It shows it's not just computation exactly.

It still takes insight, maybe luck the right approach. There's still an art to it alongside the science.

Okay, this has been absolutely fascinating. Let's try and wrap up. We've gone from simple letter swaps to enigma machines and computer analysis. What are the big takeaways for someone listening.

Well, I think understanding the why encryption is for secrecy and what the difference between cipher's letters and codes words. We've seen how methods evolved getting more.

Complex, substitution transposition, polyalphabetic.

Right and then the counter effort cryptanalysis using tools like frequency analysis, pattern finding, and now massive computing power. It's really a story of ingenuity on both sides logic, language, maths, and for.

Me, the aha moment is just seeing how even really complex looking jumbles can have an underlying logic that, with persistence and the right technique, secrets can be unlocked. It's a testament to human cleverness, really.

It absolutely is. And understanding these older methods it's not just history. It helps appreciate modern crypto, the stuff protecting our emails and bank details. The principles often build on these foundations.

So if someone's interest is really spark by this, where should they go next? What resources does the book suggest?

Oh plenty along ast Crypto's site, Klauschmez, cipher Brain blog, great Reads, the American Cryptogram Association for Puzzles. Mystery Twister is an online platform lots of places to learn more or even try solving some yourself.

Great suggestions. Start simple, Maybe try a caesar or a simple substitution from a puzzle book.

Definitely get a feel for it.

Okay, fantastic. So as we finish this deep dive, maybe a final thought for everyone in our world so full of digital encryption algorithms, we barely understand. What can we still learn from these old school, hands on methods.

That's a great question to ponder.

And maybe are there still secrets hidden in plain sight, not necessarily encrypted, but just overlooked patterns, hidden meanings in the area every day world, waiting for someone to notice.

I think that's very possible. The human element, the intuition, the observation, the aha moment that was so crucial in historical code breaking, maybe it's still just as important for uncovering all kinds of secrets, not just coded ones. Perhaps the biggest secrets aren't always locked behind digital walls.