1
$\begingroup$

Part of an alphabet is given by the code:

Cipher

This code is used by Fred to send a message home to his mum. She receives the following signal which includes a parity check digit on each word.

000000110111101011111111010010101110000011010

I have to find the message? I have tried solving directly but runs out of combinations. I need some hint or is there is some standard way to solve this question.

$\endgroup$

migrated from crypto.stackexchange.com Mar 27 at 13:59

This question came from our site for software developers, mathematicians and others interested in cryptography.

4
$\begingroup$

Given that every fifth digit is for parity check, your initial knowledge is:

00000 01101 11101 01111 11110 10010 10111 00000 11010

That is

0000(0) S
0110(1)
1110(1) N
0111(1) D
1111(0) [space]
1001(0) C
1011(1) A
0000(0) S
1101(0)

But you know that the two missing lettes are wrong. You can suppose that their parity check digit are correct, so the first sum should be odd and the latter even. Therefore, I'd say that the first letter should be corrected in 0010 (i.e. E) and the latter in 0101 (i.e. H), obtaining the message SEND CASH.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.