Questions tagged [xor]

XOR, often written ⊕, is one of the basic operations on bits and bit-sequences. It is a building block of many cryptographic primitives (and some higher-level algorithms, like modes of operations).

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Approach used with XOR cipher in black box scenery

What's the approach used in cryptanalysis to make an decrypter for a simple xor stream cipher in a Black Box scenery with only the output?
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What does a repeated byte between two XORed hexadecimal ciphers mean?

I have two different hexadecimal strings (of same length) that I think are encoded plain text strings. Out of curiosity I XORed them and I found a single hex byte repeated for the length of the two ...
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Key size of a repeating key XOR-encrypted message using Hamming distance

To find possible key sizes for an encrypted message, I break the message into blocks with length s, ...
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Secret Sharing between $x$ parties

So for an unknown number of parties $x$, I make $x-1$ random $n$-bit strings represented by {$r_1, r_2,...,r_{x-1}$}. Where $s$ is the complete string split up between $x$ parties (yes?). I then ...
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How to determine if a generalized $\sigma$ function (similar to what is defined in SHA-2) is invertible?

Let $ROTR^n(x)$ and $SHR^n(x)$ denote the rotate right (circular right shift) and the right shift operations, as defined in SHA-2 standard. Consider any function of the form $$f(x) = ROTR^{n_1}(x) \...
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Storing secrets on a peer-to-peer network by splitting up AONT data

I've come up with a way to transform a stream of bytes such that if any single bit is modified, it cannot be transformed back into its original state. Here's how it works: Encoding Get hash ...
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How can a XOR encryption be cracked systematically?

It's given that a string, encoded in hex format, is obtained by XOR encryption of a plain text and a key. The key is unknown (not even the length). What are the ...
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Name of specific cryptography property of XOR

Given $C$ = M $\oplus$ K1 $\oplus$ K2 $\oplus$ K3 One can decrypt $C$ in any sequence, like: $C$ $\oplus$ K1 = M $\oplus$ K2 $\oplus$ K3 $C$ $\oplus$ K1 $\oplus$ K3 = M $\oplus$ K2 $C$ $\...
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how to get secret keys in xor?

1) a = b ⊕ s1 2) b = a ⊕ s1 3) b ⊕ s2 = c Is there a way to find s1 and s2 if we know many different values of a and c? 4) a1 = b1 ⊕ s1 5) a1 ⊕ s1 ⊕ s2 = c1 I think it is possible if we analysis ...
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Decrypt simple CBC message with known IV using XOR encryption

I've been given a ciphertext message, encrypted using CBC. I know that the block size is 12 bytes and I know the plaintext value of the first block. I also know that the encryption function is a ...
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Is RC4 +XOR secure for small data?

I need to encrypt transmission between my device (with AVR processor) and base. I create packet data - it will be encrypted into string: ...
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Repeated XOR decryption [closed]

I have this message in Hex: ...
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Practical solution to store a highly valuable message: what am I missing? [closed]

The answers to my previous question (How safe is XOR with multiple independent but non random keys?) revealed quite a few problems, to a degree that a new approach had to be developed. I took the ...
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How to find the key of XOR encryption in Java?

I am trying to find the key of an XOR-encrypted string in Java. It is very probable that the key is eight characters long. I have the encrypted string. I do not understand how to go backwards and ...
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Looking for the inverse of the following equation

I am working on some image encryption algorithm and got stuck. I have plaintext data value of $256$ and perform the following (all values in decimal): $$[256 \oplus 2] mod (256) = 0$$ What will be ...
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Is there any vulnerability in this scheme?

We want to design a symmetric encryption scheme. Note that the following things are true for our system: The plaintext P will change every time for a given user. A user will choose a password which ...
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XOR = Best encryption? [duplicate]

If you have a TRULY random key (in binary) and you have a text (in binary) that you want to encrypt. Can you simple XOR the key and the text? Is that secure? How secure?
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How to decode function that returns number of 1s of the XOR of (target, a number you choose, and a biased random value)?

I received this problem and unsure how to figure it out. Apparently it is possible to decode the value correctly 99% of the time. An example: Suppose the target is 20, and there is a function (let's ...
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Practical perfect security in bitwise XOR vs integer addition/subtraction cipher

XOR already provides perfect security in theory but it's hard to apply it in practice due to strict requirements. I was thinking about whether simple addition/subtraction in integer format would not ...
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Why the AES perform encryption in 10 rounds Instead of one?

I'm a Master's Degree student and researching about AES-128 encryption. My Advisor asked me a question about necessity of iterative rounds in AES. he asked:"why we couldn't encrypt a 128-bit plaintext ...

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