Fun with cryptography
(Previous challenge: Programming Challenge 9: Writing a basic game)
Before you read on:
A huge disclaim needs to be made. NEVER EVER roll your own encryption ciphers. I can guarantee you that as smart and talented programmer as you may be, you will make a mistake somewhere that will leave your cipher vulnerable. The challenges here are just for fun. If anyone does have any questions about how securely encrypt data, then please feel free to ask.
How post your answers:
Do NOT post the complete decoded string because others might want to try the same challenge. Instead, post 1 word from the decoded string and it's word number. eg "word 2 = NOT" would be your reply if this paragraph was the answer. Also please post your source code inside [ code ] and [ spoiler ] tags as it keeps the thread tidy. eg:
Quote:
In the spoiler below, I've encoded an extract from my favourite book. Each ASCII character has been incrimented by one. So the letter A -> B. Decode the string; but don't post the entire answer (see How post your answers above)
Medium challenge:
In the spoiler below, I've encoded an extract from my favourite book. Each ASCII character has been incrimented by one (so the letter A -> B) and then converted to hex. Decode the string but don't post the entire answer (see How post your answers above)
Hard challenge:
I've encoded an extract from my favourite book. I've used a symmetric-key stream cipher, the key is my user name. Use this to decode the string in the spoiler below. I've deliberately kept things vague here to present a challenge, however I will give a hint in that the encryption is very basic.
I've kept all the challenges pretty basic, so that everyone has a chance to solve them.
Happy coding and please remember to post your answers using the etiquette outlined in How post your answers (above)
Bonus Challenges:
(Previous challenge: Programming Challenge 9: Writing a basic game)
Before you read on:
A huge disclaim needs to be made. NEVER EVER roll your own encryption ciphers. I can guarantee you that as smart and talented programmer as you may be, you will make a mistake somewhere that will leave your cipher vulnerable. The challenges here are just for fun. If anyone does have any questions about how securely encrypt data, then please feel free to ask.
How post your answers:
Do NOT post the complete decoded string because others might want to try the same challenge. Instead, post 1 word from the decoded string and it's word number. eg "word 2 = NOT" would be your reply if this paragraph was the answer. Also please post your source code inside [ code ] and [ spoiler ] tags as it keeps the thread tidy. eg:
Quote:
Easy challenge:
In the spoiler below, I've encoded an extract from my favourite book. Each ASCII character has been incrimented by one. So the letter A -> B. Decode the string; but don't post the entire answer (see How post your answers above)
Gbs!pvu!jo!uif!vodibsufe!cbdlxbufst!pg!uif!vogbtijpobcmf!foe!pg!uif!xftufso!tqjsbm!bsn!pg!uif!Hbmbyz!mjft!b!tnbmm!vosfhbsefe!zfmmpx!tvo/!Pscjujoh!uijt!bu!b!ejtubodf!pg!spvhimz!ojofuz.uxp!njmmjpo!njmft!jt!bo!vuufsmz!jotjhojgjdbou!mjuumf!cmvf!hsffo!qmbofu!xiptf!bqf.eftdfoefe!mjgf!gpsnt!bsf!tp!bnb{johmz!qsjnjujwf!uibu!uifz!tujmm!uijol!ejhjubm!xbudift!bsf!b!qsfuuz!ofbu!jefb/
Medium challenge:
In the spoiler below, I've encoded an extract from my favourite book. Each ASCII character has been incrimented by one (so the letter A -> B) and then converted to hex. Decode the string but don't post the entire answer (see How post your answers above)
55-69-66-21-49-6a-75-64-69-2e-49-6a-6c-66-73-28-74-21-48-76-6a-65-66-21-75-70-21-75-69-66-21-48-62-6d-62-79-7a-21-62-6d-74-70-21-6e-66-6f-75-6a-70-6f-74-21-62-6d-64-70-69-70-6d-2f-21-4a-75-21-74-62-7a-74-21-75-69-62-75-21-75-69-66-21-63-66-74-75-21-65-73-6a-6f-6c-21-6a-6f-21-66-79-6a-74-75-66-6f-64-66-21-6a-74-21-75-69-66-21-51-62-6f-21-48-62-6d-62-64-75-6a-64-21-48-62-73-68-6d-66-21-43-6d-62-74-75-66-73-2d-21-75-69-66-21-66-67-67-66-64-75-21-70-67-21-78-69-6a-64-69-21-6a-74-21-6d-6a-6c-66-21-69-62-77-6a-6f-68-21-7a-70-76-73-21-63-73-62-6a-6f-74-21-74-6e-62-74-69-66-65-21-70-76-75-21-78-6a-75-69-21-62-21-74-6d-6a-64-66-21-70-67-21-6d-66-6e-70-6f-21-78-73-62-71-71-66-65-21-73-70-76-6f-65-21-62-21-6d-62-73-68-66-21-68-70-6d-65-21-63-73-6a-64-6c-2f
Hard challenge:
I've encoded an extract from my favourite book. I've used a symmetric-key stream cipher, the key is my user name. Use this to decode the string in the spoiler below. I've deliberately kept things vague here to present a challenge, however I will give a hint in that the encryption is very basic.
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
I've kept all the challenges pretty basic, so that everyone has a chance to solve them.
Happy coding and please remember to post your answers using the etiquette outlined in How post your answers (above)
Bonus Challenges:
- Can you answer any challenges with 1 liners?
- 2 challenges using Block Transposition Cyphers (post #14) courtesy of hajile.