• need a hint for 7 bit conversion

Question related to mission Bit Message



I got stuck in calculating a correct message content for the 7 bit case. Parsing the header is easy, however I did not manage to get the target message of the first assertion with the content 'message':

assert(checkio('002080629173148007EDF27C1E3E9701') == ['26 Aug 2002 19:37:41 GMT +2', 7, 'message']), "First Test"

The message has a length of 7, such that according to my understanding the following hex pairs contain the message:

ED -> m F2 -> e 7C -> s 1E -> s 3E -> a 97 -> g 01 -> e

According to the spec, the first bit of every hexpair, should be replaced by 0.

If the first bit of 0xED is replaced by 0, I get correctly the letter 'm' (0xED becomes 0x6D which is 109 in base10 and ord('m') == 109). However I can not get the letter e using this approach. Also, the letter 's' has two different hex pairs (7C and 1E).

Even when taking continuous blocks of 7 bits (without ignoring bits), there still seems no way to reconstruct the desired codes.

Maybe Im overlooking something ?

kind regards, Andreas