A simple secret sharing between 2 person

Hi.
I am a newbie in this and I wish to know if a idea of secret sharing
between 2 persons is good.
The ideea is:
1) encrypt the data using a block cipher (like AES)
2) give the even position bits to the first person and the odd position
bits to the second person.
Example: if the data encrypted is: 01011100, the first will receive the
bits 0010 (the first, the third, the fifth,etc... bits) and the second
will receive 1110 (the scond, the fourth, etc.. bits).

AFAIK the block cipher needs the whole block to decrypt the data.

How secure is this scheme in the case if the encrypt/decrypt key is
known by the both persons? Also, how secure this could be if the data
shared is big (like few MB or even GB)?
Thanks for answers.
Received on Thu Sep 29 21:41:28 2005