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Questions tagged [encryption]

This challenge is about or related to encoding a plaintext, usually with one or more keys.

12
votes
7answers
765 views

Let's Encrypt It!

Challenge The challenge is to encrypt a given string, using the rules as specified below. The string will only contain lowercase alphabets, digits, and/or blank spaces. Equivalent of a Character ...
8
votes
3answers
505 views

Secret Message Part 1, Elements

You and your friend want to send each other secret messages. However, because you are conspiracy theorists and think that the government has a quantum computer that can crack any standard encryption. ...
18
votes
5answers
631 views

Codebreakers and Codewriters

Let's say you have some text, and you want it to send it to your friend, but you don't want anyone else to read it. That probably means you want to encrypt it so that only you and your friend can ...
17
votes
10answers
799 views

Simple encryption for people on a byte budget

Overview Your goal is to implement RC4 encryption. RC4 encryption, invented by Ron Rivest (of RSA fame), was designed to be secure, yet simple enough to be implemented from memory by military ...
19
votes
16answers
1k views

Decrypt xor-encryption

Your task is to take an encrypted string as input, and output the string decrypted, to reveal it's hidden message. The strings, both the input and output, will contain characters from this list of 64 ...
5
votes
3answers
325 views

Straddling Checkerboard Cipher

The Straddling Checkerboard is a method for converting letters to numbers and was part of a pencil an paper cipher known as VIC To convert letters to numbers first you have to make a checkboard like ...
16
votes
2answers
718 views

Golfing end-to-end encryption

This challenge carries a bounty of 200 points for the first to answer and remain unbeaten for at least 3 days. Claimed by user3080953. There's a lot of talk lately about end-to-end encryption, and ...
3
votes
2answers
180 views

Keyboard Encryption [duplicate]

Challenge Given a string with any characters a-z or A-Z, return an 'encrypted' string, where all characters are replaced by the character next to it (assuming a QWERTY keyboard). Case (uppercase, ...
13
votes
19answers
1k views

Implement this key cipher

Implement this key cipher Goal Use the algorithm (explained in the Algorithm section) to implement a certain cipher. The program must read input from STDIN or the closest available equivalent, use ...
-1
votes
1answer
144 views

Encrypting and Decrypting Challenge [closed]

Encrypting Challenge Your encrypting program must be able to do following things: Input password Generate random key Encrypt random key with set key Then, the decrypting program must be able to ...
16
votes
1answer
1k views

Implement the Enigma Machine

The Enigma machine is a fairly complex cipher machine used by the Germans and others to encrypt their messages. It is your job to implement this machine*. Step 1, Rotation Our enigma machine has ...