Questions tagged [cipher]

A cipher is a simple method of modifying messages to make them unreadable, but still possible to recover. Common ciphers are Caesar, Vigenere, Atbash, and several types of substitution cipher. Other ciphers include polynomial ciphers such as Playfair, Foursquare, etc.

Filter by
Sorted by
Tagged with
22
votes
3answers
2k views

The cook was fired!

What word am I looking for? The cook is fired! Decay! The baker's dozen! I need a new job. Hint #1: Hint #2:
22
votes
2answers
3k views

What is this mysterious image?

Recently, my friend who lives in Italy sent me an email. This was its contents: Hi, I've got some news which you should be happy about. But I've seen you around on Puzzling.SE, so I though I'd ...
22
votes
3answers
2k views

Down the Rabbit Hole

There's a secret hidden in the text below. What mind-blowing truth does it reveal? Not imaginative? Then Zeke's Clues may assist! Unsure, lad? With our patented Obscurity Clues, begin verifiably ...
22
votes
1answer
3k views

This is an opportunity. Can you take it?

The first thing you hear on awakening is the clock. It sounds just like the one you have in your room. But what you see defies what you hear. You've never seen this room before. You don't remember ...
22
votes
2answers
2k views

The Temple of Puzzling

Part of the Community Metapuzzle, although it can be solved on it's own. The password in the puzzle below is also the word needed for the Metapuzzle. Link to the metapuzzle by Deusovi is here. ...
22
votes
3answers
1k views

Something New(ton)?

Recognized as one of the most brilliant scientists of all time, Sir Isaac Newton was always ahead of his time.On the cusp of something brilliant, late in 1704, he had the idea to send you a coded ...
22
votes
2answers
2k views

The Riddling Tree

Decoded message, which now needs to be solved) Amongst the trees one stands alone, Through the ages he's aged and grown, Here to tell all that see, Of their desperate, despairing plea. ...
22
votes
1answer
1k views

Romance and Higher Learning

I as sorting through my books the other day and I came across an old philosophy textbook. When I saw what was scrawled on the back, it brought back a flood of memories. It was almost the end of my ...
21
votes
4answers
6k views

Hidden in plain sight - By what method do these images hide a prime number?

Note: This question has been severely edited from its original version to better fit the format of this site. Some answers below - including the accepted, correct answer - have been given based on the ...
21
votes
1answer
799 views

Open the curtains

Open the curtains to reveal some words of wisdom: ...
21
votes
2answers
1k views

Weird messages from a friend

I'm really worried about my friend Friedrich, until today I haven't heard anything from him for the last few weeks. I decided to message him and ask if anything is wrong, and he responded with some ...
21
votes
1answer
530 views

The Dots of Creation

Along the road less traveled, an abandoned temple lays in ruins. Though it has suffered the wrath of time, its foundation remains strong. And within this place, an inscription remains visible. A ...
21
votes
1answer
1k views

A very strange letter

Today, you receive an unusual delivery in the mail - a plain white envelope marked not with your address, but a question: What’s my sign? You open the envelope to find two pieces of paper with the ...
21
votes
1answer
1k views

My Grandfather's Final Message

As my grandfather reached the end of his long and satisfying life, I sat by his bedside and asked him what advice he could give me to help me in my own. Unable to speak, he pointed to his bedside ...
21
votes
3answers
904 views

Master Bomb Defusers

Day 115 of your investigation and you and your ever-faithful-if-only-a-bit-slow partner have finally caught the trail of your arch-nemesis, a serial bomber known only as "Mr. 5". Doing your ...
21
votes
0answers
1k views

CSE Hex Cube Puzzle

I've been tackling this puzzle named "Hex Cube" from the CSE (Communications Security Establishment, the Canadian "equivalent" of the NSA) which comes with the instructions: "...
20
votes
6answers
1k views

50th Puzzle Landmark: My exciting exploits with Adedayo, Prince of Nigeria

Today marks a very exciting day for me. Today will be my 50th puzzle on this site, and as such, I've created a challenge the likes of which I have never done before. I hope it to be my most ...
20
votes
4answers
4k views

Assassination in an office (again)

Inspired by a puzzle posted not that long ago. A man was killed in an office. We have five suspects: Isaac - takes care of trash in the company Caleb - he once stole two dollars from a ...
20
votes
2answers
2k views

Not another one! ²

That's right, I have received yet another note! Who passed it to me this time?
20
votes
8answers
4k views

What is the cipher behind this circular cyphertext?

I have a cipher and I am wondering if - provided you have both the cipher-text and the clear text, given below, can you describe the cipher which was used? The cipher-text is in this image: I ...
20
votes
3answers
2k views

My Friend in Kanto

I have a friend in Kanto. He sent me a message and told me that he's looking for all sorts of creatures. Included was the following list of descriptions. I know there's a message hidden in there ...
20
votes
3answers
951 views

An Odd New Technology

Since it's Friday, and I'm really looking forward to the weekend, I've created yet another riddle for everyone to try and solve. The Puzzle I was in my chemistry class the other day, and I noticed ...
20
votes
1answer
890 views

How are my puzzles?

Today, I told my friend about Puzzling SE and sent him the link to some of my puzzles. His reply came, "Your puzzles are such a $50$ $96$ $5$". "What do you mean to say?" I asked. He sent me this: ...
20
votes
1answer
1k views

Always log off from your Facebook account

It began with a normal Saturday afternoon. Judy, driving off in a rush from the garage, forgot to log off from her Facebook account on the computer. Her husband Andrew took the chance to scan through ...
20
votes
2answers
540 views

Preparing for the end of term performance

It's the first full week of term at Farthingbottom School and Portia, Felix, Primula and Randolph have arrived in the music room for their lesson. Professor N. Igma is nowhere to be seen, but he has ...
20
votes
1answer
2k views

11 Harry Potter rebus puzzles which together spell a word

11 Harry Potter rebus puzzles. When you have solved them all, there is a word they are hiding. Hint:
20
votes
1answer
502 views

An encoded message for Nigel

Nigel came inside from his back garden carrying the peas he'd harvested, and dumped them onto the table to be sorted according to which were edible and which weren't. Just as he did so, he noticed a ...
20
votes
1answer
699 views

Aki's favorite game

After introducing you to my new little friend Aki, it's time to reveal what his favorite game is! What is the new hobby of the little Aki? Hint 1: Hint 2: Hint 3:
20
votes
1answer
740 views

Old code for the new year

Here is a question I posted on rec.puzzles back in 1998. So it's about twenty years on, and people seem to have stopped thinking about it. I'll refresh your memory by posting it again: I wrote a ...
20
votes
1answer
2k views

Ricky McCormick's Notes

On June 30 1999, Ricky McCormick was found dead in an isolated area, 15 miles away from his home. He didn't own a car, and the area was not subjected to public transport so it is a mystery how he got ...
19
votes
6answers
4k views

Who lives in 314?

You've been invited to room 314, but who lives in 314? Hint 1: Hint 2: Hint 3:
19
votes
3answers
3k views

End of the Maze

This the final installment of the Maze series. Here is Room 1 and here is the previous room. After you enter the answer from Room 5, you wait for the door to de materialize as usual, but nothing ...
19
votes
6answers
4k views

A weird and spooky clock

Out of nowhere, a clock appeared on my desktop: (you don't have to be able to view the GIF in order to solve it, I think the "preview" image gives you all the minor clues hidden in it. I ...
19
votes
1answer
2k views

What does this message say?

I have a very... odd... friend. We were talking the other day and I texted him asking him his favourite food. He replied with the following: ...
19
votes
4answers
2k views

Escape The Strange, Code-Filled Cave

You awake in a weird cave with something strange written on the wall. You find a small piece of paper on a rock. It says the following: Solving each code and entering it into the password entering ...
19
votes
3answers
2k views

V for Vendetta - Who am I?

This link here shows how many "Who am I?" riddles we already have on this site. Obviously, there are many of them and they're mostly riddles describing an object in some funny way. On checking the ...
19
votes
2answers
964 views

Why didn't this kid get any presents from Santa?

He counted the days until Christmas every morning, lunch and evening. He made a huge wishlist of presents; a RC car, flashy shoes and much more. He couldn't wait until the day that he could show off ...
19
votes
2answers
3k views

Murder of a Cryptologist

Your friend, the Cryptologist Mr. Toboggan, has been murdered in his house. You being a detective and a Cryptologist yourself have been asked to lend a hand in solving the murder. You arrive at the ...
19
votes
1answer
641 views

Monoalphabetic Geometry

This is a second puzzle from the Monoalphabetic Equation series, you can check out the previous one here. A set of letters has been replaced by $a$, $b$, $c$, and $d$ and one symbol has been replaced ...
19
votes
1answer
1k views

Sweet! Dream! Another hyper-modern art piece

This puzzle belongs to the puzzle series: hyper-modern art After cracking the door code of the last room, the two friends in the gallery of hyper-modern art are moving on to the next room. "Oh, look ...
19
votes
1answer
1k views

Oh God! help me

I have just fluffed my exam. See, Grades don't matter to me but it apparently does to my parents and the head teacher who has asked me to write a letter explaining the reasons of my disastrous results....
19
votes
1answer
516 views

Fun with Flags part 7: attention please

We are looking for an idiom. Hint 1: Hint 2: Other (independently solvable) puzzles of this type: 1, 2, 3, 4, 5, 6, 8, 9, 10.
19
votes
1answer
601 views

Flying pigs arrive

You’ve built pens for flying pigs. Being, well, flying pigs, they pick their own accommodation in full accordance to their preferences. Can you figure out what creature joined them? Pigs only occupy ...
19
votes
4answers
602 views

Baby don't hurt me no more

You've been taken captive by a spy organization who seems convinced you're an agent for the other side. You've already spent a miserable day of questioning and torture and have no wish to spend ...
19
votes
2answers
1k views

Pixel Cipher Puzzle

You are given the following plaintext/ciphertext pairs: they_got_my_contract_back_to_find_ to_their_alarm_a_dog_had_signed_ sonic_boom_sonic_boom_sonic_boom_ ...
19
votes
3answers
807 views

What force is more potent than love?

A few quotes about Love.... What force is more potent than love? True love is selfless. It is prepared to sacrifice. We are all born for love. It is the principle of existence, and its ...
19
votes
4answers
1k views

Six Series, Six Words

Update: I've just realized the image had a major flaw in it. I've added a new image and made sure it's correct. Nothing else has changed, only the image. Sorry for the inconvenience. I have six ...
19
votes
1answer
772 views

What lesson did he learn?

Kevin is a vegan. But not the good kind of vegan. The kind that insists everyone in his neighborhood needs to stop cooking meat at dinner time so he can run outside. Kevin pushed everyone around him ...
19
votes
1answer
1k views

Unknown transposition cypher puzzle

The text is: ...
18
votes
2answers
1k views

Box of text contains hidden message

I invented a novel encryption technique that hides a message in the below text box. ...

1 2
3
4 5
33