Re: Unbreakable code using XOR for one time pad?

Bill B <wrongaddress@xxxxxxx> writes:

Encoding data using the XOR function against a "one time pad" of the
same or longer length of the file seems to yield an unbreakable cypher
message since there is more than one solution using different keys.

For example, the message "The quick brown fox" can be encoded by
XORing each character against a key of say
"abcdefghijklmnopqrstuvwxyz" producing a cyphertext message of decimal
characters '"53,10,6,68,20,19,14,11,2,74,9,30,2,25,1,80,23,29,11"

Decoding this message using the original key produces the
original message of "The quick brown fox"

However, if the cyphertext is XORed against a different set of decimal
key characters of say;
"97,98,99,100,120,114,116,114,34,56,108,122,34,125,110,55,55,61,43,
116,117,118,119,120,121,122" the output will be:

"The lazy red dog"

So, it appears that using a one time pad (single use of key)
will yield an unbreakable code, since there are many solutions
to the problem. In other words, using the appropriate key will produce
whatever results are desired and the original message can never be
found without knowing the correct key.

Have I missed something?

Had you looked up "One Time Pad' you would have found a description
equivalent to what you state. And a proof of its security essentially the
same as yours.s. You would also have found out why it is problematic-- that
key can NEVER EVER be reused for anything which means that you have to
somehow securely exchange a key larger than any message or set of messages
you will ever transmit.



-Bill
.

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