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The XOR cipher is often used in computer malware to make reverse engineering more difficult. If the key is random and is at least as long as the message, the XOR cipher is much more secure than when there is key repetition within a message. [4] When the keystream is generated by a pseudo-random number generator, the result is a stream cipher.
Using the XOR swap algorithm to exchange nibbles between variables without the use of temporary storage. In computer programming, the exclusive or swap (sometimes shortened to XOR swap) is an algorithm that uses the exclusive or bitwise operation to swap the values of two variables without using the temporary variable which is normally required.
On July 22, 1919, U.S. Patent 1,310,719 was issued to Gilbert Vernam for the XOR operation used for the encryption of a one-time pad. [7] Derived from his Vernam cipher, the system was a cipher that combined a message with a key read from a punched tape. In its original form, Vernam's system was vulnerable because the key tape was a loop, which ...
The bitwise XOR (exclusive or) performs an exclusive disjunction, which is equivalent to adding two bits and discarding the carry. The result is zero only when we have two zeroes or two ones. [3] XOR can be used to toggle the bits between 1 and 0. Thus i = i ^ 1 when used in a loop toggles its values between 1 and 0. [4]
The R2 register always contains the XOR of the address of current item C with the address of the predecessor item P: C⊕P. The Link fields in the records contain the XOR of the left and right successor addresses, say L⊕R. XOR of R2 (C⊕P) with the current link field (L⊕R) yields C⊕P⊕L⊕R.
0010 (decimal 2) XOR 1010 (decimal 10) = 1000 (decimal 8) This technique may be used to manipulate bit patterns representing sets of Boolean states. Assembly language programmers and optimizing compilers sometimes use XOR as a short-cut to setting the value of a register to zero. Performing XOR on a value against itself always yields zero, and ...
The stream cipher produces a string of bits C(K) the same length as the messages. The encrypted versions of the messages then are: E(A) = A xor C E(B) = B xor C. where xor is performed bit by bit. Say an adversary has intercepted E(A) and E(B). They can easily compute: E(A) xor E(B)
We are padding C n with zeros to help in step 3. X n = D n XOR C. Exclusive-OR D n with C to create X n. Looking at the first M bits, this step has the result of XORing C n (the first M bits of the encryption process' E n−1) with the (now decrypted) P n XOR Head (E n−1, M) (see steps 4-5 of the encryption process).