38 lines
603 B
C++
38 lines
603 B
C++
#pragma once
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#include <cstdint>
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#include <cstddef>
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#include <algorithm>
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class RC4 {
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public:
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void init(const uint8_t* key, size_t keyLen) {
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for (int k = 0; k < 256; ++k)
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S[k] = static_cast<uint8_t>(k);
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uint8_t j = 0;
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for (int k = 0; k < 256; ++k) {
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j += S[k] + key[k % keyLen];
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std::swap(S[k], S[j]);
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}
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i = 0;
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j = 0;
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}
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void process(uint8_t* data, size_t len) {
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for (size_t n = 0; n < len; ++n) {
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i += 1;
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j += S[i];
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std::swap(S[i], S[j]);
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uint8_t k = S[(S[i] + S[j]) & 0xFF];
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data[n] ^= k;
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}
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}
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private:
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uint8_t S[256];
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uint8_t i = 0;
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uint8_t j = 0;
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};
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