How to actually decipher one of Blindspot's very difficult tattoo clues

Blindspot type TV Show network NBC genre Drama

Mystery

Thriller

On NBC’s new drama Blindspot, Jane Doe (Jaimie Alexander) was dosed with an experimental memory loss drug, covered in tattoos and left for the FBI to find naked in a bag in Times Square. Quickly in the pilot, one of Jane’s tattoos is easily deciphered, helping the FBI prevent a terrorist attack on Liberty Island. But decoding these tattoos, which the producers promised everyone could do at home, is not as easy as they make it seem. What follows is a real account of trying to do so:

Let’s go back to August when I spoke with executive producer Martin Gero: He provided clues on two of the upcoming tattoos. One of the tattoos that will be featured in the second episode include a set of numbers and letters that read 399/IHRTVLALVKBBHHJ/7, which was magically going to provide a person’s name.

Image zoom Warner Bros.

Here’s exactly what Gero teased:

“Well, that’s super fun because that’s actually a puzzle that there’s no official address or anything. You could figure that out. To solve this clue you need to have unlocked the tattoo clue from the pilot. Luckily we’re going to do that for you. That’s all on us. We’re going to decode this thing in the pilot, and then using the tattoo clue that we uncover in the pilot that sends us off on our pilot case, something should twig for you with this series of numbers and letters, and there’s an encrypted message hidden in there that can actually be decoded by anybody that figures it out.”

Easy, right? Wrong. Oh, so wrong. The tattoo in the pilot — Chinese lettering behind Jane’s ear — was solved by her literally translating the language — the Wenzhounese​ dialect, specifically — to the day’s date and a street address: 399 White Street, Apt. 7. You’ll notice a very glaring similarity between the tattoos from the pilot and episode 2: The numbers 399 and 7 bookend them, which tells us that they are connected somehow.

While rewatching the rest of the pilot, I realized that there’s no way I could actually decipher this based on what Gero had said — I clearly don’t know Wenzhounese​, which was needed to solve the clue in the pilot — which led me to drafting an email to Gero conceding defeat … until I got to the end of the episode and NBC literally spelled out the answer during the trailer for episode 2. Somehow 399/IHRTVLALVKBBHHJ/7 translates to MajArthurGibson. A quick search online provided me with the logline for Monday’s episode that, in part, says: “The team unlocks a cryptic tattoo that points to Major Arthur Gibson (guest star Robert Eli), an Air Force pilot with a painful past and a lethal agenda.”

Image zoom

But how, NBC? How did they get that answer?! I wouldn’t be swayed. Now I was even more determined to find out how they did it, even if I already knew the answer. My email to Gero changed:

“Finally got to watch the premiere again in an attempt to decode that tattoo from the magazine story. I was having a tough time decoding it and had drafted a whole email to you on why I was having a tough time… until I just got to the trailer at the end of the episode, which reveals this tattoo! Maj. Arthur Gibson. But I’m honestly stumped as to how, so you’ve got to tell me. This was what my original email was going to say: I know the Chinese behind her ear roughly translates to 399 White Street, Apt. 7 and the date, though the date isn’t revealed. You said anyone could decode the letters and numbers if they decoded the tattoo clue from the premiere, which you do for us, but decoding it just means reading Chinese. Also I don’t read Chinese, so I couldn’t tell you if that’s the right translation. Help me, Obi Wan, you’re my only hope.”

Yes, I was initially determined to figure it out myself, but as you can see in my email, I was just desperate for answers. However, Gero wasn’t going to let me off that easy. By the by, in my imagination, Gero was sitting behind his computer screen, laughing that I could not solve his apparently easily solvable riddle, because I got a quick response:

“399 White Street Apt 7. What does this have in common with the episode 2 tattoo?”

I played it very cool (and not at all frustrated) in my response:

“The 399 and the 7 at the end.”

His response, as I’m sure he continued to laugh maniacally like an ’80s film villain. Kidding. Probably:

“Great. So. The words inbetween might help you unjumble the letters on the second tattoo. One more hint available. But it will tell you how to solve it.”

The next two hours were filled with internet searches of various ciphers and codes. I now know the basics of Caesarian shifts, Affine, Baconian, Keye Caesar and Columnar Transposition — though, really, I now know they exist. There was also one random cipher I kept seeing pop up, Vigenère, but it involved having a keyword, which I know I didn’t have, so I ruled it out immediately (and stupidly). Finally, I called it a night, firing off an email to Gero saying that I’d be back at it in the morning, so do not give me any more hints. Twirling his mustache, Gero responded:

“It’s a cipher. The question is…what kind?”

On day 2, it was becoming silly that I hadn’t figured it out yet. With the cipher clue in hand, I valiantly … searched “Different types of ciphers.” Not kidding. I came across that Vigenère one again, which started to feel like a sign that I was overlooking something vital — which, in fact, I was. I did have a keyword staring right at me: White Street Apt. A very long, but 14-letter keyword. So I then popped this into a Vigenère cipher generator (What, I was tired! What if I was wrong?!) and the answer it spit out was correct: MajArthurGibson.

Because that was way too easy, I decided to actually learn how to decrypt and encrypt using the Vigenère cipher table, which looks like this:

Image zoom Wikipedia

First, you’ll want to write out your encrypted message on a line, like so:

Image zoom

Then, you write out your keyword below so the letters will correspond. In this case, the keyword is one letter shorter than the message, which means you would start the keyword over from the beginning, using the letter W twice. If the message was longer, you’d continue using the keyword over and over. Also, when using a keyword, you ignore spaces — which is what caused me to ignore White Street Apt. as a potential keyword.

Image zoom

In short, a message encrypted using the Vigenère cipher means each letter in the message is replaced by a letter some fixed number of positions down the alphabet. Unlike the Caesarian shift, which uses the same method, there is a different shift for each letter in the message, which is determined by the keyword. Let’s bring up that table again:

Image zoom Wikipedia

On the table, the vertical axis is the keyword, while the horizontal axis is the actual message. Using the table, you’d find the first letter of the keyword on the lefthand vertical side. In this case, it is W. Along the W axis, you’d go horizontally along that row until you hit the first letter of the encrypted message, which is I. Scrolling up to the top of the table, you’d see that corresponds to the letter M. Boom, you just figured out the first letter! Continue the process until you get the actual answer and feel like a genius … before realizing you already had the answer and probably would never have figured it out without it.

Image zoom

My final message to Gero, ultimately conceding defeat because, well, by even emailing Gero, I totally cheated the process:

“Vigenère. I had been looking at ciphers last night and had seen that one pop up a number of times. Finally when you confirmed cipher (jerk, I said no more hints!), I passed by it again and actually found one that would do it for me, which gave me the correct answer. However! I wanted to find out how to actually use it myself, so that’s what took me so long to reply. I wish I didn’t have so much help on this one though. Mulling turning this all into a story. Wondering if it will sound funny or just sad.”

In short, sad. Oh, so sad.

Blindspot airs Mondays at 10 p.m. ET on NBC.