i want to decipher the message below using the key(κλειδι) . can you help me please?

[Walter Roberson]

http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags

[Walter Roberson]

Sorry, few of the regular volunteers can read the instructions in Greek, and as you posted an image rather than text, we cannot copy and paste into our favourite translation software to find out what the question is asking.

[stavros patsalidis]

key : ZOMBIESACDFGHJKLNPQRTUVWXY message : MKJSPZRQ XKT BCQMKUIPIB RAI HIQQZSI

Actually is just like this! i want to decipher the message using the key!

[Stephen23]

@stavros patsalidis: please stop posting multiple duplicate questions for every topic that you have. Duplicate questions do not get your problems resolved faster, they actually just make our (volunteer) lives harder to know what info you have provided and what answers you have been given.

http://www.mathworks.com/matlabcentral/answers/253732-i-want-to-decipher-the-message-below-using-the-key-can-you-help-me-please

Answer 1

[Geoff Hayes]

stavros - given that your key has all twenty six letters in the (modern) English alphabet, we can probably assume that the key is just a rearrangement or mapping of the ordered alphabet. For example,

 alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
 key      = 'ZOMBIESACDFGHJKLNPQRTUVWXY';

where A is mapped to Z, B is mapped to O, etc. If that is the case, then we can decrypt the message by reversing the mapping. For example, the first character of your message is M and that is in the third position of key. This could mean that the decrypted M is just C. So here is the pseudocode for your decryption algorithm

• iterate over each character in the message
• determine where (i.e. index) in the key this character is
• map this key to the original character in the alphabet

If you convert the above into MATLAB code, you will be able to decrypt the message. I was able to! :)