Welcome to tech Stuff, a production from my Heart Radio. Hey there, and welcome to tech Stuff. I'm your host, Jonathan Strickland. I'm an executive producer with iHeart Radio and how Tech Arenia. Well, it is time for a classic episode of tech Stuff. This episode originally published on April fift two thousand fifteen. It is titled how Steganography Works and it is not a Dinosaur. I can't remember if actually made that joke in this episode. I guess we're gonna find out. Let's listen. This is an ancient listener request, folks. So, Peter, I apologize that took so long for us to get there, but I'm really excited that we get to cover it today. Here's what Peter wrote. He said, I recently bought a book called Data Hiding that is about steganography. I look to see if this is something you have covered, but found you had not. I think that this would be an extremely interesting topic. You would be able to cover the ways in which data can be hidden, as well as who uses such techniques like al Qaeda, the n s A, malware, authors, hobbyists, et cetera. Yeah, we're going to cover steganography, which is not what I originally thought it was. I originally thought it was the study of Stegosauri stegasaurces. Yeah, I thought it was the study of dinosaur calligraphy. So we were both on the wrong track, as it turns out. Uh yeah, So what actually is steganography. Well, steganography is the art of hiding something within something else. It can be simple, like a hidden message in a painting or photograph, or it can be something really complicated, like an electronic file or message hidden in another file or message. Yeah. Yeah, So it's essentially the the art of being able to send a message without people even knowing that you've done so, right, That's that's the goal of steganography. So the parties in steganography are there, are you know? This is how we break it down. You've got the cinder that's the person who's created the message and wants to communicate something. You have the receiver, which is the person who the message is intended to go to. You have the carrier message, which is the the the construct that hides the secret message. So this could be whatever, Like, it could be a painting, the boring note about your cousin's children, or it could be a soccer ball that happens to have a secret assage written on the inside of it. It could be that Wilson in Castaway was in fact Stagana Graham, which is the other element. So, by the way, there are a lot of Greek words and Greek names and some Roman names, so Latin as well, that's going to be all of those are gonna be popping up. There also a couple of other names from other cultures. I'm an ignorant American, so my pronunciation is going to be awful, and I can barely grasp the American language, which I've grown up with all my life, so mine will be work. Yeah, So just just letting you guys know that ahead of time. So the ski staganogram say, I'm never going to get that, otherwise known as the secret message. We're just gonna I'm going to call it secrets just from now on and then potentially third parties. So in other words, people who might come into contact with this message. The goal is to make sure that those third parties are never aware that there is a message there in the first place, and if it's done right, they won't be Yeah. So in other words, you could have a messenger a go between carry this thing from one person to the other and never know that there was something hidden in there. Although sometimes it's good if they're confident, because you need to get a message to the person who needs to decipher it on how to decipher it right, right. If the person who receives the message isn't aware of the method to find it, it doesn't do them a lot of good. So if if you have been able to collude with your receiver left, if I'm sending a message to Ariel, and Ariel and I have decided ahead of time, Hey, if I ever need to send you a message, this is how I'm going to do it, and this is how you're going to see what the message is, then we're okay. But if if it's a situation where Ariel and I have been separated for a long time and I need to send her a message and I needed to be secret, I've got to figure out a way to give her instructions as to how to retrieve that message. And sometimes that involves, you know, paying somebody, like just tell her to wash the wax off, and we'll explain what that means a little bit later. So there, wash the wax off, the Yeah sure, yeah, I mean just in general. So we've got the elements here. Those are your basic elements to to have Steganography actually makes sense, And now we need to talk about the difference between that and a related art cryptography, which, yes, cryptography is the art of making and solving codes. Uh, but anybody can see that it's a code. Right, So if I send a coded message to arial, it may be that any third party can't see what the message is, but they know I'm trying to communicate to her, Yeah, because why else would he send me a piece of paper that says music of yeh, unless I've just fallen asleep on my keyboard, then clearly I'm trying to say something. So and then I'm just wasting my time trying to decipher. Right. So, cryptography keys in people that something's going on. It lets people know there's some sort of communication. And uh. You might have a pretty simple type of code, like a simple cipher where you know the old classic uh substitution cipher where you substitute one letter for another, the simplest being let's shift all the letters over by one. So and uh, whenever I write the letter B, I really mean the letter a. Whenever I write the letter C, I really mean the letter be. This is what's called a really bad cipher. It's easy to figure out. I don't know. When I try to do the cryptograms in puzzle books, had such a hard time, And it's the same thing. Well, sometimes a substitution cipher can get a little more complicated. So for example, when you substitute one letter for another, then the next time you substitute a letter, you actually shift over again. So in other words, the first time you only shift over one letter, the second time you shift over two letters, the third time you shift over three letters. So if you know the algorithm, if you know the pattern, then when you get the message, you can reverse that and you know to look for it. If you don't know the pattern, then you have to spend more time trying to figure out what the pattern is. And while that still is a fairly simple example, things like the um the Enigma machine in World War Two, which was the Germans way of sending coded messages. They had this machine that had three different The basic one had three different dials that they had set. And then I had a typewriter and a bunch of lamps and when you pressed down a key of a letter, a lamp would light up, indicating a different letter. So let's say I typed the letter E to type in Enigma, but the letter for in lights up. Then it would actually go a certain number of steps, so that the next letter I type would be a totally unpredictable letter. If I didn't have an Enigma machine of my own. Well, that's really good, because if I tried to write a cipher, I would totally lose place of where I was if I was constantly shifting the letter, and my message would be nonsensical, both decrypted and encrypted. Yeah, exactly, that that is. That's the reason why the Germans were using a machine so that way it could be predictable, but only if both parties had the same style of Enigma machine and they both knew what the initial settings were, so part of the communication would include a a key saying this is what you need to set it to. Although technically they were all supposed to have a communication telling them what settings to use each day, and they were never supposed to repeat those settings. Eventually people got lazy, and that's how those codes were eventually broken by Alan Turing, which you can see in that film, the imitation game, the imitation game exactly. So steganography obviously is different from cryptography, and that yes, you're still sending secret messages, but the message itself, the existence of the message is secret. Anybody, any layman looking at the message or the photo or the paper won't know it's there, right, So you you can still encrypt it. You can still use cryptography. In fact, using both together makes a lot of sense. But ultimately with steganography, if you've hidden the message well enough and people are not if people don't know to look for it, it's safe to be in plain text to whomever you're sending it to, depending upon what method you use, because there are a lot of different ones, right um um. A great way to further explain it is to go back to the Greek. Cryptography means secret writing and stag atography means covered writing. I pause there because I was really surprised I said it correctly. Well, every time I say it correctly, I will also be surprised. Uh yeah, So that really that gets down to the heart of it, right, And the combination of the two allows you to have more secure communication. Now, there's an art to finding hidden messages that have been concealed in this way. Yes, it is called stag analysis, which I tried to look up what the Greek of that meant, and it meant covered breaking up, loosening of Yeah, so it's it's all very repetitive. It just means you're uncovering the secret message, right. So depending upon the type of uh steganogram that has been sent, you would use a different method to find the meaning. So when we're talking about the modern version of steganography, we're really talking about ones and zeros digital information. So stag analysis is largely concerned with that because that's that's the main way messages are sent these days, is through a digital file of some sort that to an outside view looks like a normal file. There's nothing that seems remarkable about it. But if you were to analyze the actual digital information of that file, you would start to see patterns that would indicate something hanky is going. Yes, and in steak analysis, there are two steps to deciphering and the first is detecting it um, which if if it is like a handwritten message or something like that, and it's very fairly obvious, you can do it without any special software. UM. But where it does happen so much in the digital age. Um their disk analysis programs that will just look at it for you. Yeah, you actually run your suspected uh secret message. So it could be very simple like a lot of and a lot of examples I see are photographs that have been uploaded to public forums and the idea being that well, when it's in the public eye, no one's paying attention to it because it's just something that we see all the time. Like if you were to post a picture to Facebook, yeah, a lot of a lot of people do. Then because that's so common, it doesn't tend to raise suspicion. So first of all, someone has to know that there's something to look for, right, they have to first be suspicious that there's some form of communication going on. Then they have to start figuring out, all right, how is this communication happening, And then they would have to start targeting the various means of that, and one of those might be photographs, and they'd say, all right, let's take this image that was uploaded to whatever site, and let's run it through one of these disk analysis programs and see if that comes up with anything that perhaps there's some indication that something's out of place, and it might be something that you looking at would notice if you knew what to look for. Yeah, that's called perceptible noise. So sometimes if audio visual files are slightly off, there might be perceptible noise in there. So that would just be an indicator, right, something saying something's not right now. That can happen naturally, like that could just be a problem with the file and not not be an indication that there's anything super secret going on, or it could be an indication that, in fact, some of the bits in that file have been altered in order to send a secret message. And in in the best case of stegnography, you wouldn't have weird noises or distorted pixels for people to see. Yeah, it would just be so subtle that you would never pick up on it. And uh and that's the reason why you need these disc analysis programs, so they can look for things that are below the perceptive level of human beings. Uh. So again we often see the two working together makes a lot of sense. So let's talk a little bit about the history of steganography, because there are some gloriously awful and bloody stories just just reading about them. Yeah, So first, we gotta go to ancient Greece, which makes sense. We're talking, you know, we're using Greek words, so it makes sense that that a lot of the early cases involved Greek stories, and we're gonna be talking a lot about Herodotus. I can only do it because I listened to the pronunciation and I wrote down a phonetic translation in our notes. That is not a joke. Herodotus was a Greek historian in the fifth century b c. And wrote a lot about Greek history and the history of the surrounding areas of Greece, And in fact, his writings were called the Histories. Yeah, and or at least we have to we have to take some of this with a grain of salt, because legend got mixed up with history quite a bit. So in fact, there are some modern accountings that suggest that some of the familial connections he makes in his stories were not necessarily accurate. So um one of the big ones, in fact, the first one I have to talk about, is one of those where the story talks about a general named Harpagus who sent a staganagram to Cyrus, was a king who was going to become the king of kings of Persia, Son of Persia, not the Prince of Persia. Now that's a video game, which is fun, but not not something we actually need to reference here. The story, Yeah, the story is far bloodier in fact, which is odd to think of, depending on which version of Prince of Persia you played and how badly you played it. But Cyrus was going to be the king of kings of Persia. So Persia was divided up into several kingdoms, and then you had a sort of an over king who saw over everybody, kind of like King Arthur in in English lore Um. So cyrus Um was the grandson, according to Herodotus, to another king of kings, Ostiagas, and so Harpagus actually worked for Ostiagas. So Ostiogus is this king of kings, and he has a dream, and in his dream, his daughter gives birth to a son, and that son grows up to depose osti Agus. So first he ends up marrying his daughter off to a kind of milk toast kind of guy, someone that he thinks is, oh well, this guy is harmless, so any child they have is not going to be a threat to me Um. And they have a son named IRUs. According to Herodotus. Again. Other modern accounts suggests that Cyrus and Ostiagas were not grandfather and grandson. Yeah, they might have been related, but not like grandfather and grandson, particularly since Cyrus ended up marrying um a daughter a Herodotus, which would have made he would have married his own aunt, which was not common in those times. So I mean possible, but not common. So anyway, in the story, Cyrus is the grandson, and Ostiagas decides Harpagus needs to go out and kill Cyrus. Okay. Harpagas, though, does not really relish the thought of spilling royal blood. So he takes Cyrus and he gives Cyrus to a shepherd and says, look after this kid, uh and raise him as your own, and I will report back that Cyrus is dead. Seems like a really decent guy, at least at that point, so he goes back. He reports that Cyrus has died, and Ostiagus says YEA. Ten years later, Ostiagus finds out Cyrus is actually alive, so he punishes Harpagus in kind of a Shakespearean awful way, and that in the story osti Agus gets Harpagus, his son kills him chops him up, cooks him, serves them to Harpagas as a banquet Harpegas and then tells Harpegus, hey, by the way, I hope you like your son, because that's what you're eating. Harpegus supposedly then gathered up the remains and gave his son a burial. He was being obedient to the king outwardly, but inwardly had decided that he had had enough and he wanted revenge, so he wanted to report to Cyrus. He He ended up working very hard to get other leaders of Persia to turn against Ostiagus and wait for just the right time to give Cyrus the signal that now is the time to attack. So he needed to send a message to Cyrus saying we're ready to go when you are. But asti August had guards all along the way. So how does he send a message. He gets a bunny bunny hair. Actually, no, they're not nearly as cute as bunny rabbits, and this hair was not nearly as cute because it was did Yeah, they they have a guy kill a hair. They cut the hair open, they insert the secret message into the hair's stomach, so the hair back up and a messenger disguised as a huntsman brings the hair to Cyrus and says, you should cut open this bunny rabbit and get what the delicious things inside are. And so Cyrus cuts open the stitches, gets the message, sees that it's time to attack, and that is how, according to Herodotus, Cyrus goes and joins a revolution and overthrows Ostia Augus and then Cyrus becomes the king. So there's a long way to go for that story, but it's important to know all the elements to explain why Harpagus was trying to send a coded message in the first place, or hidden message. I'm so glad we have better ways to send hidden messages than in the stomachs of rabbits. Now, okay, this is Jonathan from the future. I've got a hidden message in this image file that says we need to take a quick break, but we'll be right back. So um, here's another one. This is another popular story from Herodotus. This one involves a tyrant named Histius, which sounds like you're strangling a snake. Yeah. Histius who was the ruler of mild Us, and this guy was really useful to the king of Persia. The King of Persia loved Histius and decided to invite him back to become a royal advisor. Well, that sounds it is pretty good to me. Well at first, Histories thoughts so too. But then eventually he thought, you know, I want to go back to being a tyrant of Maltest. Tyrant, by the way, does not necessarily mean evil ruler, but it did mean like having total authority over a region. Um, so he said, he thought, I want to go back to doing what I was doing before. But it would be treason for me to deny the king? So how do I get around this? And he comes up with an even more treason this way to get around it. He decides that the best way to get back to doing what he was doing before would be to stage a revolution back home. Uh, and then tell the king, Hey, I need to go back there and squash this revolution before it gets out of hand, because telling the king no is so much less worse than lying to the king and tell him. So, he decides he needs to send this instruction to his nephew, who was in charge of maldis Agris. And so how does he send the message, Well, he gets a slave which the Greeks had back then, and tattoos. He shaves the slave's head, tattoos the message on the slave's scalp, then allows the slaves hair to grow back, then sends the slave to Aristagoras with the instruction to tell Aristagoras, Hey, you need to shave me and read my head. So that's exactly what happens. Aristagoras reads the message, starts a revolution against the Persians. Then Histius tells the king, Hey, this is gonna be a problem, so just send me back and I will go and squish this right away, and we'll solve this before it turns into a big problem. And of course they can go a loyal advisor. Sure. Yeah, So Histius heads on his way back. However, there were some folks who were a little suspicious of Histius and his convenient revolution, and so eventually Histaius goes on the run because people are actually after or him thinking that you know, he's he's committed treason. Yeah, he has done that thing, and so he ends up getting exiled and eventually to an island. He becomes a pirate for a while, and then he's eventually captured by one of the king of Persia's subjects. Who knows that if he sends his tis back to the king, the king will pardon him, So he just goes ahead and execute his t is right then and there, since the head of his is to the king saying, hey, I caught him and killed him for you. And the king actually supposedly gave the head of his tis an honorable burial because he never suspected anything was up. He didn't believe his is could have committed any kind of treason against him. So uh, dumb or nice? Not a lot of nice stories in ancient Greece. Uh, And then you've got another one, another herodotist story, another herodotus story. I was out to mention it, and then I realized that I couldn't actually say his name. There was an exiled Greek named named Demeritus, and uh. He needed to warn the king of Sparta, Leonidas that kings er Ses the first was going to attack them. So he took writing tablets, which were wood tablets covered in wax and you would scratch a message into the wax, and instead he took off all the wax and scratched message into the wood, and then recovered the tablets and wax so that they looked like they were blanked tablets, and he sent those to the king to warn him. Uh. But proposedly no one knew why they were getting these blank tablets. They didn't necessarily know there was a message. Why are we getting just we got plenty of tablets and no one writes anything of use here in Sparta anyway. Yeah, supposedly the queen, Queen Gorgo figured out what it was, said, you got you need to take the wax off. I but there's a message under there and there were um but it didn't help them because the Spartans were brutally defeat it. Uh. And if the story sounds familiar to you, it's because it is the story three the comic movie. Yeah story, that's essentially that's the tale the three hundred Spartans who who tried to hold a pass and managed to delay xer c S so that the invasion of Greece ultimately would fail. But the Spartans were completely wiped out, or at least the the three hundred were completely wiped out as a result. Moving forward to Roman times, Tacitus invented a way to use a predecessor of dice to hide messages. So these these dice like things which I can't remember the name now. It's like an estralla alley or something like that. But I know I've totally mangled that, so I apologize. But they had little holes drilled in them, and you could string them together, and in this case, uh, Tacitus was using them to string them together in specific orders to relay different type some messages. But if anyone were stopped with them, they just looked like it was a toy. It didn't look like it was anything of significance, although they might play with it and mess up the message. That Yeah, if you were to break the thread so that they were no longer threaded together in the proper way, then the message would be lost. Uh. This, by the way, it would end up having a specific name a semigram, because it is being used as a non text based message. So you don't you don't translate it into texts so much as you say, this series of symbols means this particular thing. Uh. You also have a guy named Johannes Trithmius in the Middle Ages, in the sixteenth century actually, who wrote a book titled Steganograph Stega Nagraphia yes, which was a stagram in and of itself, this I did not know, which is pretty cool. Yeah. It outwardly it seemed to be a series of writings on magic, but in secret it contained a message on the treatise of Steganography. That's now that's really cool that you're like, Okay, you've gotta be smart enough to know that this is a book about secret messages, because it itself is a secret message. Uh yeah, really interesting, and then we can skip ahead. I mean, obviously these have been used repeatedly in multiple ways. There's another great example that during World War One, the German embassy in the United States sent a message to Berlin that used what's called a null cipher. Null ciphers are not very secure at all because once you know that there's a possibility, it's very easy to find them. But basically it's when you take the first letter of each word in a message and that spells out a new message. So here's an example that's often cited. I don't know that this was ever actually sent as a message, but it's always used as an example. Here's the the full message, which was or the carrier message, if you will. It was President's embargo ruling should have immediate notice. Graves situation affecting international law, statement for shadows ruin of many neutrals, yellow journals, unifying national excitement immensely. See, they really had me until the yellow journals. Like I was following that message, I knew what they were trying to send. Well, they could have been talking about yellow journalism, but that's a different thing anyway, and you wouldn't know why a German embassy would write about it. But at any rate, the secret message, if you take those first letters, says Pershing sales from n y New York, June first or June I, upper case I. So Pershing was the U. S General who led American the American expeditionary forces in World War One. So this would be a message from German, the German embassy to Germany saying, Hey, this American general is sailing out of New York on this date. Expect him to be in the in the European theater within several weeks. That kind of thing. Uh. And now we'll talk about some of the types of steganography, because there's a whole bunch of because really, any way that you can hide a message inside something is technically steganography. So these are just some examples. Really, it's not an exhaustive list because that would be impossible. For instance, uh, there's the old Greek ways we talked about um in in history of hiding something inside or under something. Great example is in the Second World War, the British Secret Service hid escape kit pieces in monopoly games and sent them to the prisoners of war in Germany along with Red Cross supplies. Yeah, so you could you get these deliveries if you're a prisoner of war, and you know, the Germans would say, all right, well this is just humanitarian aid or whatever, and as long as it keeps the prisoners mollified, then we'll go ahead and give them to them, not realizing that they were supplying the prisoners with the very tools the prisoners might be able to use to break free, which is pretty interesting. And by when the prisoners break free, did they have egg on their face? So the semigrams I talked about earlier, the dice that are threatened together, that's just one example that could be in lots of different versions, like iconography or signs or photographs, or even like the placement of items on a desk. So let's say I've got I could have a webcam set up on my desk, for example, so that people who log into the web could see me, you know, theoretically just working at work like that's all I'm doing. But maybe depending upon where my coffee cup is, or depending upon where a certain stack of papers happened to be, that might be an actual message itself. So Ariel looking at the webcam might say, oh, well, Jonathan's gonna go to Manual's Tavern today because I see where the combination of stuff is. I don't know why I would secretly be telling you that, because all of your fans trying to follow you. Yeah, that's it. I'm surrounded by the thronging fans. Who And Manual's Tavern is such a low profile place, right. Uh that's by the way, if you're not from Atlanta or never been here, Manual's Tavern is a very popular spot for artists and and playwrights and political fans and sports figures. Political figures. Yeah, President Obama came here recently, and it's just kind of it's kind of like a like I think of it like cheers. Yeah, it's really like cheers with chickens. On the roof. Yeah, yeah, there are chickens on the roof. That that's not it's not a joke. They use their eggs for breakfast, they do. Another example would be the car done grill. It sounds like a good restaurant. It does, doesn't it. It's a classic example. I was first proposed in the fifteenth century. So here's how it works. You've probably seen this. So you take a sheet of clean paper or in the case of the Middle Ages, parchment, and you set that down. You take a second sheet and you cut little holes in that sheet and strategic places. You lay the second sheet on top of the first sheet, and then you write in your secret message in those holes, using the holes as kind of like almost like a stencil. And so it's only bits and pieces. Sometimes sometimes it might be a word. Sometimes it might just be a single letter. But you do that throughout, using the holes as your guide to write the secret message. Then you take your stencil off and you write in the You fill in the rest of the space with a boring message. That means you know very little in the grand scheme of things. So only someone who would have a part a comparable stencil, so something that they have a sheet of paper that has the same general holes cut out of it. They could lay that on top of the full message and read the secret message that's underneath. I actually tried to make a card and grill a while back back when I was in school and do a secret message like that. It is harder than I imagined it would be because once you put your secret message in, you then have to make sure the rest of your message lines up right. You have to make it make enough sense, like how do you plan out the rest of your message so that you can do this unless you are to create a message from the very beginning, and then you create a grill that fits on top of your existing message that shows what which words are the most important, and then you send it. But then you've got to figure out, well, how do I get how do I get the grill? How do I get the the stencil to the person I need to send it to? Because if I send both, then clearly the jig is up, you know, So it is a little tricky. I love this next one You've got. Yeah, this next one. I had to double check it because I didn't think it was possibly real. But people would knit Morris code into garments and then send those garments on the couriers for people to decipher. And you think it was just like a knit line of Yeah, just a pattern, just a pattern, yea on clothing. I think that's super cool. I want to start doing that when I have kids, I'm gonna knit Morse code into all their clothes. They'll be fantastic things like things like do your chores if this child is found. Well, that's a I like that you expect eyes to come across your children because I can't think of anyone else who typically uses Morse code on a frequent basis. Uh. I like the next one too, which is also pretty cool, the idea that just through through formatting a document, you can create a secret message. Yeah, you can add an extra space, which most people don't notice. I do a lot of editing at my job, and so I often see extra spaces at before after a period, or before a certain word, like before a hyphen or after a hyphen. But you can add those extra spaces before the important words in any word that you find that has an extra space before. That's part of your cipher. Nice. I've also seen where you could do things like subtly change the font, yes, like really subtle, like courier to courier new which is and a casual glance it looks the same, but if you're paying attention, you can tell the difference, and thus you put the important words in the different font. And as long as the messages, like as long as your carrier message is long enough and your secret message is short enough, people are probably not going to pick up on it. You can also vaguely change the skew as well. That that one's a little bit more noticeable, right, right, So it's you know, some of these again can get pretty risky if your secret message is pretty long. This is true in general, right, The longer your carrier message, the more secure the secret is going to be, assuming that the secret is not itself very long. If I have, like, if I'm trying to hide a secret message in a tweet, that's gonna be hard because they only have a hundred forty characters to start with. Yeah, and then if I'm trying to hide a message in that, then it has to be a pretty small message. Otherwise it's just gonna look like a tweet. It would probably have to be a cryptogram, yeah, where individual letters mean full things. Or right, or or like just a regular code where someone has a codebook and they know that when I use this word that that means something else. Yeah, in that case, that would that would be more of a code and ah than than a secret message in this sense. But there are the ones too. There's also an invisible ink, which is a thing. People have actually used it for reals and also it's usually called sympathetic inc in the biz. Because you would have a regular message written out in normal inc that would have, you know, very boring, you know, no reason to raise suspicion. You would write the actual secret message and invisible ink kind of between the lines, and then the person who receives it would have to treat it. However they need to treat it, usually like adding a little heat or maybe adding a certain chemical to bring out the invisible ink so that you can make it legible, and then you would be able to read the secret stuff. And another way to hide messages would be through photography. Yeah, like the Pueblo incident, which as far as stagonography goes, is kind of like a semigram where uh crew of the USS Pueblo was captured by North Korea right before the Vietnam War. They were an electronic intelligent ship and they were forced to take propaganda photos, and in those propaganda photos, they all rested with their hands on their faces or their shoulders in a very nonchalant way, and it was actually a code for the US to decipher. That's pretty incredible. It really is so similar to what I was describing with the webcam, the idea of just having this this foresight that you know clearly you thought ahead, so that the person who sees it knows what the meaning is behind whatever you're whatever the images. Yes, and there there there are more complicated versions of that. For instance, there you can systematically change pixel colors to correspond with letters in the alphabet and then only change like the first pixel every square centimeter or millimeter in photo or every so many lines, and people can get the message that way. That. Yeah, that's definitely really very subtle, especially you know if you're using things like black and white photos, where you can you can change those things and they're not called out as much, because you could make it like a square that was going to be very dark a much lighter gray, and if you know what to look for, then you could see the pattern but otherwise you might just think, oh, this is just poor developing or whatever. It's it's the it's a graininess of the photo. Um. You could use an existing piece of text, like a newspaper. This was used during the Cold War all the time, where uh you would use like a pen to put tiny holes above important letters, and then so you would grab the newspaper hold it up so you can see where the holes were, and that would give you the letters to spell out or sometimes a full word to spell out whatever the secret message was. UM. Or you might use a dot with invisible ink if you wanted to make sure people like could pick up the newspaper and hold it up and not see light coming through at strategic locations. But then of course you would have to treat the newspaper to whatever it was that you know, would bring the invisible inc ounts are really important and steagatography like they're used in many way. Yeah, yeah, there's I actually got to see examples of this because I went to the Spy Museum which is in Washington, d C. And they had examples of micro dots. And micro dots are kind of think of it like micro film. It's tiny little bits of film that look like a period. That's how small they are. And unless you were to hold it up and see that it was in fact film and not just a solid blob of ink, you would never have suspected of being anything other than a punctuation mark. And it can hold an incredible amount of information because you know they're There are ways to enlarge photos. We're talking about the old film style, right. This doesn't mean you can do it digitally too, but we're talking old school. So there are ways where you could take a photo and then blow it up and blow it up and blow it up so that you get like a poster size or larger. Well, there are also ways where you could shrink it down and shrink it down and shrink it down, and uh, I was reading one way that cuts so technical that I gave up on the chance of trying to even describe it. But ultimately they said it was two hundred and ten times smaller than the original photograph. And so you could take a picture of say a document, top secret document, and then you shrink it down to this size so it looks like it's a you know, a period. You just cut out a little piece of the paper, you insert this in and to casual glance, it seems like it's just a regular sheet of paper with punctuation. But when you are in the right hands, which might be the wrong hands, depending on what side you're on, then you can find out, um, what is actually there. This was a process that was created by a man named Emmanuel goldberg Um and used it for spying, and very popular, particularly amongst Soviet Union spies at the time. I would imagine nowadays if you used micro dots in a digital format, it would be a lot harder to detect because you couldn't hold up the paper and see the something was amiss, Yeah, yeah, it was. It's the game has changed significantly, and by this time, obviously we're talking about something a lot more subtle than a dead rabbit. Yeah. But but sometimes we can have things that are just as irritating as maybe a dead rabbit would be, such as spam the mickry uh disguising messages that you want to send as spam emails or nonsensical musings or what not. You do this by messing up the placement of the punctuation, or the type of the fonts, or the grammar of the message. As a means to communicating the secret. Yeah, I love this. I actually saw an example of this where, uh, someone used grammar as the key indicator, and so you would read the message and whenever you found a grammatical error, that was actually an indicator that this is where you need to pay attention. Uh, that was kind of interesting. Well, you would think it would be easy to decipher, but with as much spam email as everybody gets nowadays, you don't even think to look, well, right, yeah, you just especially if you were to broadcast this, so that it's not something that just one person gets, because again, we're all used to getting that spam. Most of us would never even look twice at it. We would just see, oh, spam message deleted. So you could actually have security by sending it to lots of people, because then it looks like it's quote unquote legitimate spam. That seems like a weird thing to say, but that's that's where it is. Now we're getting into the more modern versions where this is where we need things like a disk analysis software in order to discover it. We have a little bit more to say about steganography, but before we get to that, let's take another quick break. So digital files. Let's talk about these in general, and this can refer to pretty much any kind of digital file like audio, video, images, any of that sort of stuff. So we all know digital files are made up ultimately of strings of ones and zeros. Yeah, so here's the thing. Some of those bits are more important than others. Not all bits are equal. Some of those bits are not so important. So if you were to pick the least significant bits or l s B s, you can do something called the least significant bit insertion, which is where you alter a bit, and by altering a series of bits, you can create a message. Now, it takes several bits to make just one character in the alphabet, so you have to be very succinct with your messages because the more of these you mess up, the more likely that will it will be detectable by somebody who's paying really close attention, either close attention to your activities or close attention to the file. So if you do it well, and you and you're very careful with it, most people are never gonna notice. And this is what we talk about when someone posts an image to a public forum and there's a hidden message in those bits. Uh Yeah, And generally speaking, you want to go. If you're making one of these, you want to go with a lossless format as opposed to lossy compressed versions, because technically you would normally create this this message in the lossless fine style and put it in there and then allow it to be compressed. So if it's a lossless format that then is compressed, you don't lose any information that way. Uh. These compression algorithms are very good at keeping the original information in tact, so that way you know your message is not going to get altered lossy formats. The way lossy formats work is they look for information that doesn't seem important and then they drop it, and that's one of the ways they compressed the file size. So if you put a secret message in a file that's then going to be compressed in this way, your secret message could be part of the stuff that gets dropped or altered and then you can't communicate. So if you do want to post a picture with a secret message on Facebook, you should use a gift instead of a j pick right, unless you insist on pronouncing it Jeff, in which case I don't even want to talk to you. Did I say you said gifts? Thank goodness. See that's the way I pronounce it too. I don't because it if you put a T at the end of that, it's a gift and G stands for graphic. That's a good sound, not a Jiuh, don't get me. But that's again not the only type of digital information that could be altered, right, yeah, I mean you can also alter the audio files. I think we talked about this already. By yeah, I mean not just not just digital audio, like not just m P three but even void calls, voice over Internet protocol calls. Yeah, you could. And there's also water market. Yes, there is digital water marking, which is used to protect intellectual property and by embedding information like the creator and the copyright and et cetera into the file. Um. And that way, if people try to claim it as their own, they could say, nope, here's my water mark. See it's got all my little information in there. Sure. Um. They also use digital water water marking in a method called fingerprinting, where they put a different, unique water mark on each copy of the document or information they send out. And that way, if someone tries to copy it or send it out themselves to people who shouldn't get it, they can say, oh, all of these have that unique water mark, so we know who sent it. Bobby's in trouble because this is the version that we sent to Bobby, and everyone else got a different uh digital watermarks, so we narrowed it down. We know who is at fault, or we know who was compromised. Their security might have been compromised. That's really cool. Uh yeah, then we've got subliminal channels, which is not probably what you think it is. It isn't like messages secretly in movies or playing my music back where there's nothing like that. No, it's not like John is dead, missing Miss Simmons, none of that. Uh. Now, this is something that was proposed in by a mathematician and cryptographer named Gustavus J. Simmons Uh and Simmons poet proposed something called the prisoners problem, and it's a thought experiment. This is the way the thought experiment works. You've got two accomplices who are captured during the while they're trying to commit a crime. Okay, Bob and Jen Narcott. Usually it's Bob and Alice actually, so we got half of them already. But Bob and Jennaricott. Uh, and there put into the same jail, but Bob is put in one cell. Jen has put on a cell on the opposite end of the jail, so there's no way for them to communicate directly. The warden is told, hey, these two want to be able to talk. What how do we do that? And the warden says, all right, here's the deal. You will be allowed to communicate to each other, but I get to see everything you send to one another. So that way, if there's any messages about trying to break out of jail, I'm going to get it immediately and you're gonna be stopped. That's a nice warden, because I'd just be like, you guys can't talk to each other, deal with it. It gets nicer actually because Bob and Jen say, all right, but we want to make sure that our messages are genuinely coming from the other person. And we want, in other words, we want to make sure that you, Mr Warden, aren't going in and messing up our messages. So we want to be able to authenticate that our messages come from each other. So we have to we want to be able to come up with a way to say it's essentially a signature to say yes, this actually came from Bob, or yes this actually came from Jen, and the warden says, well, all right, if you if you agree to my terms, I agree to your terms. We can all do this. What Simmons said was, if you're willing to give up a little of that authentication security, you could take some of the authentication message. Let's say that it's one fifth as long as your actual message. Still would be really long for authentication, but let's say so let's say that then you change some of that authentication which normally would look like it's random, like it's supposed to look random, so that way, uh, you know, it's it's not if it's predetermined in a way that everyone knows about, like if everyone knows the key and the algorithm, then there's no authentication there. Uh. But instead of it actually being random, it just looks random, and you've actually changed some of the authentication message so that that's where the secret messages. It's not within the body of the actual message, it's in the authentication. Uh. Now that was just a thought experiment, but turned out that that's actually the way. A lot of this is a lot of uh, steganography happens today too, is that it ends up being in the authentication kind of like the digital water mark, rather than in the message itself. And that is an example another example of how steganography and cryptography work together. Yeah, but is authentication is all about cryptography, so it's it's manipulating the two. So let's talk about people who actually use this stuff. Not a big surprise. Yeah, that's a that's a big one. In fact, again, at the Spy Museum, I saw example after example of this kind of stuff. If you've never been to the Spy Museum, by the way, if you ever go to Washington, d C. I recommend it. Um. I recommend going early because it's a very it's it's a museum that fills up with kids, and kids are great, despite what I say about them, but they do make it difficult to maneuver through the museum and see everything. It sounds like a lot of the stuff in the Spy Museum might be pretty technical for a kid. Yeah, it can definitely go over a kid's head. There's a lot of reading because there are a lot of descriptions that explain what the various devices and pictures and everything, what they mean and there's some very interesting videos, but for kids they'd be really boring. Oh it's one of those things where like the idea of spies is really super sexy and exciting and oh, James Bond, kids are gonna have fun. But ultimately, I think you need to be like a teenager or older. Maybe maybe not necessarily a teenager, but like eleven or twelve to really kind of start thinking, oh, this is kind of cool. Younger, I think it gets lost on you. Although they have some cool interactive stuff too, but you don't get to play with like shoeguns or anything. Now that you don't get to play with shoeguns, but you do get to assume a secret identity. They give you a secret identity and you have to remember certain facts about yourself so that if you're ever stopped and questioned, you can answer with your cover. So if you forget your cover, you're caught that So, so here's an example of spies who use steganography. In two thousand nine and two thousand ten, the FBI arrested ten covert Russian sleeper agents who had been communicating in multiple ways, including stecken bography. Uh, they'd be posting those photos that I was talking about, the same sort of thing. They would post photos to public forums, which in fact included the secret messages that could be picked up if you ran them through analysis. But you know, if you use that software, you can pick them up, but otherwise you probably wouldn't notice. They also used other things like in this blink and they would do secret bag swaps, like classic spy stuff like we'll meet in the trade station, I will give you bag, you would walk away. They got discovered because of the photos they were posting, right well, they that and the fact that all right, so the photos you had to run them through a particular piece of software to decode what the message was, to pull out the letters that were hidden inside these photos, right Because one of the problems with with binary code is we humans, we don't read it so well. So that's why we need software to be able to pull that stuff and say, all right, here are the bits that are important, here's what translates into. So one of the things they needed was security to make sure people couldn't access the software that would decode everything. So they had a password that all of them had to share. It was the same password they would type in to the software to allow them to decrypt something. And it was a twenty seven character long passwords. So that's pretty secure except someone wrote it down, so the FBI gets hold of the written password. By the way, folks, if you write your password down and someone finds it, guess what, You're not being secure. I don't care how long your password is or how many upper and lower case letters you throw in there. Uh. So, the FBI found the password, they were able to intercept messages, they were able to round up these ten sleeper agents, and ultimately they were exchanged in a prisoner swap with Russia. UH. Russia had four prisoners, three of whom had been accused of high treason, all of whom were Russian citizens, but they had all been colluding in some way or another or been accused of colluding with the United States or the United Kingdom. So these four were swapped out for the ten that were found in America. And it was all done kind of quietly because there were still, I mean there still are today uh tensions between the United States and Russia, and no one wanted to make that worse. Yeah, man, could you imagine being one of the ten agents? And you're worth not even being half a person. Well, and not only that, but those ten people who went back to Russia, they were not technically put in prison, but they were detained for weeks for debrifing. So things did not go well for them, not for all of them anywhere now, especially probably not for the one who wrote down the past words. So then we have examples in military and government. Now, governments traditionally aren't crazy about steganography software getting out into the wild because they don't want people to be able to use it. Yeah, especially uh foreign countries. They're actually have been laws put in place to keep us from sending strong encryption software. Yeah. There there's been a lot of debate in government about whether or not it should be legal to export encryption software, and there's been a lot of argument on either case, and only that the government wasn't crazy about having public arguments about this, or having arguments on the public record, because that would mean people would find out that such a thing even existed, and they were worried that even people finding out that such software was possible would create more incidents of people using it. So there was probably yeah, but but it was it was a sort of a catch twenty two. You know, they were like, well, we need to talk about this, but we can't talk about it because if people know we talked about it, they'll know that it exists. Um. I have a quote from meeting about how to handle this that said a substantial amount of material is not appropriate for a public meeting. That's exactly what I'm talking about, Like, we we can't debate this because if it's on the public record, it will cause problems. Um. Now, despite that, there ultimately there would be uh allowances for exporting uh this encryption software because business doesn't have to do business um, and we want our businesses to be secure. Yeah. So then we have terrorists who also have used steganography. The there was there were reports after the nine eleven attacks that al Qaeda had been using steganography techniques to communicate. They were actually supposedly using pornography. They were hiding their messages there because who would think to look for secret messages in that very very much so. And also they were thought to be less likely to have used them because it goes against their very world view. But that's what made it a perfect place to hide a message, and people were worried that maybe they got the the tools from US, right yeah. They were worried that they got the encryption tools from those same companies that had argued that they should be allowed to export their products, and in fact, it created a lot of soul searching on the parts of those people. They said, well, are we responsible? And ultimately they came up with the conclusion that even if a ban had been put in place, even if they had never been allowed to sell their products, someone else would have come up with the same thing because there was a need. And so once you identify a need, someone's going to come up with a solution. And there are people who send stuff they shouldn't send all the time, just just the challenging authority aspect of it. They're like, oh, we shouldn't be using this or giving it to other people, so we're going to write right yeah, there's the whole argument of information wants to be free. And with that you would say that, well, if you're the harder you try to keep information away from people, the harder people will try to make sure they get that information. But having encryption software go out to foreign places and being developed in in other places than the US means that we have drive to create better encryption, right and decryption and decryption. Yeah, so it actually it pushes it pushes the art forward. And this is something we also see an artificial intelligence, where we see as one part of security gets better, uh than people find new ways to make that security vulnerable, and then the security gets better. And while individual attacks are terrible or individual like vulnerabilities are terrible, the overall story is that stuff gets better over time. But that's you know, that's a hard view to take, depending upon the particulars in this case, a very hard one to take. Also, writers and journalists have used steganography sometimes just to entertain. Like there's this guy h Brown, Charlie No, Dan, Yeah, he wrote, he wrote a couple of books like Angels and Demons and Da Vinci Code. It's almost said Da Vinci's Notebook. That's totally different but really good. Yeah, some we're familiar with their work there, but it's not the SAME's. They might have messages in their music. Well I'm sure there are. There are some, probably some very important messages and things like the Magic Castle in the Sky so entitle of the song. But yeah, so Dan Brown of course very famous for writing these books and there were lots of examples of steganography, In fact, key plot points revolving around uh steganography and various kinds of religious iconography and other elements too. I remember in Angels and Demons. I think it was Angels and Demons where I got irritated by one of them because it was a brand like a as in something you would brand an animal with heat up and right, uh, and if it's spelled out Illuminati. And then you discovered that if you turned it degree so in other words, if you turned it upside down, it's still spelled Illuminati. And then the suggestion was because it was because the way the font was designed and the way the way it was was that only someone with the secret Illuminati knowledge could ever make this thing. And I thought, that's obviously crap, because you made it, Dan Brown, in order for this to happen. So I don't know how you could suggest that only one human being would or only one group of human beings would be clever enough to do this. That's demonstrably false. But anyway it was meant for, Yeah, it's meant to be a good story. Also, artists obviously very important in stagonography, particularly in the old ways where you had to hide a message within something, you know, and sometimes it was just done for entertainment. Sometimes it was done for specific purposes to hide things. UM. I had heard that Da Vinci hit a lot of secret messages in his artwork. Yeah, we hear, we hear that from da Vinci himself sometimes. Ariel and I have both worked for the Georgia Renaissance Festival, and another a mutual friend of ours, plays a young da Vinci very well. Yeah, so if you ask him about his secret messages, he has hilarious responses for that. But the the what you're alluding to, of course, I mean, there are a lot of theories I shouldn't say, hypotheses about secret messages hidden in things like the Last Supper, which is one of the most famous paintings Da Vinci ever produced. Um, And of course, uh, the da Vinci Code ended up talking a lot about that, obviously. Uh. One of the hypotheses I saw, which was interesting was put forward by an uh I T guy in information uh information technology professional who had created a mirror image of the Last Supper, so essentially took like imagine you have Photoshop and you copy the image, but then you flip it, so now it's it's inverted the other way, and then you make it translucent, and then you lay it back down on top of the original image. So now you've got this doubled image on top of one another. And then said, look at all the interesting things that pop up when you do this. There were figures on either side that were said to look like knights templar. There was in the center in front of Jesus there appeared to be a chalice like perhaps it's the Holy Grail and this kind of thing, and that there appeared to be a figure standing behind Jesus holding a baby. H a lot of other elements that were supposedly brought to light. But that raises the question one, how could da Vinci have done this himself? Now, he was known for mirror writing, where he could write with both hands, and he could right right to left and left to right simultaneous. He would have had to have painted two pictures left to right and right to left at the same time and lay them over each other. He would have to paint two identical pictures. Yeah, and who would ever find out about this? I mean, there's no way to to see the message The whole point of steganography is to communicate to someone. If no one knows that there's a message there and no one knows how to get that message, you're not communicating, you're just shouting, you are I mean, he could have put that message in there just too or not put a message in there, but put something in there to seem like a message, just to mess with people. That's possible. But yeah, most art historians kind of dismissed these various hypotheses. Doesn't mean that they're all false. It may mean, you know, there may have been things that da Vinci threw into some uh, either as sketches or his paintings or whatever, that were either just amusements or you know, they weren't intended to be anything secret. It was just something that he incorporated into the design. It's possible, and then, you know, depending upon the guy, probable da Vinci was it was a bit of an eccentric isn't there an article about this on Yes? The article is is, uh, how the da Vinci code doesn't work? So if you want to know more about that, Yeah, there's also an article about are there hidden messages in the Last Supper? We have articles on both of those things, so you should definitely check those out at how stuff works dot com. Uh. Then there are other examples, like one of my favorites is Mad magazines fold in, which was created by the writer and artist Al Jaffee, who created originally in nine four. It's been in practically every Mad magazine since then. And if you've never seen a fold in on Mad Magazine, then and I'm talking about the actual magazine, not the television series, not Mad TV, and not a digital copy of the night No, no, you need the you need the physical one. It is the the inside back cover is the fold in, and it has two points, and you're supposed to fold one point over to the second point, and it creates a new image. So when you look at it, normally it's one image, and it's the setup for a joke, and you do the fold then it's the punchline to that joke, and usually it's it's a twist on whatever. The big pictures. And actually, Jeff, he said, if I didn't have to worry about the big picture as opposed to a little picture, I could turn out like twelve of these a day. But getting them to work together takes a lot more planning and the way he did it. He drew them all by hand on a surface that did not fold, so it had to look right when it was folded, but he while he was drawing it, I couldn't fold it to make sure it was working. After after I encountered my first folding in a Mad magazine, I actually went into a Where's Waldo book and tried to do it in there and didn't work. No, No, I didn't find Waldo any faster. No, I didn't find any secret punchline. That's a little disappointed. He did, however, ruin the Where's Waldo? Books? So there's that. Uh. Another Man Magazine contributor, Sergio Ariganez, he used to draw a comic book called Grew the Wanderer, which was about it's very cartoony. If you've ever seen Sergio Ragan as his art style, you know it's cartoony. And it was about a buffoonish barbarian character, very dim witted character named Grew g r o O and very silly. But he would hide a message in every comic book. Uh usually said this is the secret message, or something like, good job, you found the secret message. But it would always be incorporated into the artwork in some way, like in some cases it would be written into the scroll work on a really elaborate uh fret board for a loop something like that, so you would have to really look for it. And again, if you didn't know there was a message there, you probably never would have seen it. Yeah, I feel like a lot of comics have done that here and there. If you look really closely, you can find I know there are some comics who hide their name in pictures and the artwork as well, but there are other people who use them too, like system administrators UM just to make encryption extra secure, like talked about before with authentication codes UM, and then like people who just want to protect their intellectual property. You can even do it for your own personal journal. If if you write in a diary and you don't want anybody to read it, you can read what you really want to say. You can hide it in there, right, So the stuff that you write could be, you know whatever, but the actual meaning, the things that you truly want to preserve for yourself, you could hide away from from people prying eyes. So if you you know, if you if you're tired of losing that little key to your lockable journal. I know I gave up years ago. I have no idea what's in that book anymore? Um, probably best left unknown. Probably, you know, my past is a shady one at best. So that kind of wraps up this discussion about steganography, what it is, who uses it, you know, what goes into it. It is a fascinating field. I mean again, the idea of creating a way to communicate without anyone ever being aware that it was an intention no communication is I mean, it's kind of kind of awesome, it really is. And the numerous ways that people have come up with to do steganography is it's just mind blowing. I'm not nearly that creative, no, I well, mostly I don't have a lot of secret messages to send to people, so I don't have a whole lot of occasion to think on it. But yeah, it really does show people's ingenuity to come up with new ways to hide things. I hope you enjoyed that classic episode of tech stuff back from If you have suggestions for topics I should tackle in future episodes, or maybe you want to follow up to something that you've heard in a classic episode, let me know best way to do that is to reach out on Twitter. The handle for the show is text Stuff HSW and not talk to you again really soon. Text Stuff is an I heart Radio production. For more podcasts from I Heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your faith were chums.