Barrel cypher

[admin]

The goal of this puzzle is to write a barrel cypher decoder with the smallest code size possible.

The cypher works with a key and a message. The key is a suite of numbers between 1 and 9, the message a space separated list of lower case words. To encrypt a message, we repeatedly travel through the numbers of the key from left to right and then from right to left and shift the letter in the alphabet by the corresponding number.

Example

• key 1595


• message hello world

We start processing the words and using the digits from the key from left to right:

h+1=i, e+5=j, l+9=u, l+5=q

Now that we used all the digits, we do it again from right to left:

o+5=t, the space is discarded, w+9=f, o+5=t, r+1=s

And finally we repeat the process, starting from left to right:

l+1=m, d+5=i

The encrypted message is: ijuqt ftsmi

Go to puzzle

[Radu Cruceru]

Something is not right:

[sample input]
123
xgofqnf vr fqeftfkcsuu

[output]
welcome to codercharts

x (ascii 120) + 1 -> y (ascii 121)

in your case, you substract the value.
From the problem description, i understood that you have to right-shift the letters. Please clarify this for me.

Thanks

[admin]

Hello Radu,

the description explains how to encode a message A and obtain a resulting message B.
The goal of the puzzle is to decode a message B and find the original message A.

Hope that clarifies

[bknarendra]

What is maximum size of the key?

[admin]

What is maximum size of the key?

As long as the text to be encrypted. The key is never longer than the text.

[octalc0de]

"The first 30 spaces, tabs and newlines are ignored, each additional one counts as one character."

How do I get tabs? My solution technique would benefit from tabs, but if I type a tab in the text box, it expands into spaces.

[admin]

"The first 30 spaces, tabs and newlines are ignored, each additional one counts as one character."

How do I get tabs? My solution technique would benefit from tabs, but if I type a tab in the text box, it expands into spaces.

The only way to enter a tab is by copy paste. In the editor, we overload the tab key to generate 4 spaces.

[Luis Palacios]

Hi I have a solution and want to test it.. I made my PHP code and want to try it here:
http://codercharts.com/puzzle/barrel-cypher
Whats the name of the file to be decripted?

[admin]

The file name is provided as a command line argument, it was discussed in the PHP section a while ago:
viewtopic.php?f=15&t=70

Hope it clarifies

[TheSageMage]

First time coder here... so I know the scoring is based on program length? Is the language take into account(All Java scores compared to other Java) or is it any language?