as yet unanswered questions

Given my last thread, which was not informative at all, given that I
already knew what was discussed. I re-iterate my questions and in which my
questions were wholey ignored.

In this example I will assign arbitrary values to the variables IV and IV2
in the algorithm, which again has been modified since my last thread to the
group, hopefully assigning values will make it easier to read and calculate.

Some of you may remember that that in a previous thread I stated clearly
that for the mean time, I have given up on attempting to construct a block
cipher of any strength or mode. So I state again that this is a stream
cipher and an amateurish one at that.

IV = 110111112 which is the ascii value of the string 'nop'

IV2 = 112111110 which is the ascii value of the string 'pon'

IV = IV xor IV2

IV = IV mod 256

IV = IV ^ 2

This means that the value of IV is 20164

The maximum value allowed in a long integer data type is 2147483647 so K[i]
becomes

20164 Xor 2147483647 = 2147463483

2147463483 mod 256 = 59

I will assign the value of 78 to P[i]

So the equation C[i] = P[i] xor K[i] using these arbitrarily assigned
variables is C[i] = 78 xor 59, which means that C[i] = 117. This can be also
written as

C[i] = P[i] xor ((((IV xor IV2) mod 256) ^ 2) mod 256)

The attacker will know C[i], but can the attacker know K[i] without first
knowing IV and IV2. Or can the attacker derive IV or IV2 by any means other
than a brute force attack on either, as the only data contained within the
message is the MAC, the ciphertext and a ciphered nonce which when decoded
is used to defined the hashed nonce.


.

Relevant Pages

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