52 lines
1.7 KiB
Markdown
52 lines
1.7 KiB
Markdown
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# Portable C++ Hashing Library
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This is a mirror of my library hosted at https://create.stephan-brumme.com/hash-library/
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In a nutshell:
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- computes CRC32, MD5, SHA1 and SHA256 (most common member of the SHA2 functions), Keccak and its SHA3 sibling
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- optional HMAC (keyed-hash message authentication code)
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- no external dependencies, small code size
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- can work chunk-wise (for example when reading streams block-by-block)
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- portable: supports Windows and Linux, tested on Little Endian and Big Endian CPUs
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- roughly as fast as Linux core hashing functions
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- open source, zlib license
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You can find code examples, benchmarks and much more on my website https://create.stephan-brumme.com/hash-library/
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# How to use
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This example computes SHA256 hashes but the API is more or less identical for all hash algorithms:
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``` cpp
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// SHA2 test program
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#include "sha256.h"
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#include <iostream> // for std::cout only, not needed for hashing library
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int main(int, char**)
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{
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// create a new hashing object
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SHA256 sha256;
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// hashing an std::string
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std::cout << sha256("Hello World") << std::endl;
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// => a591a6d40bf420404a011733cfb7b190d62c65bf0bcda32b57b277d9ad9f146e
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// hashing a buffer of bytes
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const char* buffer = "How are you";
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std::cout << sha256(buffer, 11) << std::endl;
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// => 9c7d5b046878838da72e40ceb3179580958df544b240869b80d0275cc07209cc
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// or in a streaming fashion (re-use "How are you")
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SHA256 sha256stream;
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const char* url = "create.stephan-brumme.com"; // 25 bytes
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int step = 5;
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for (int i = 0; i < 25; i += step)
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sha256stream.add(url + i, step); // add five bytes at a time
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std::cout << sha256stream.getHash() << std::endl;
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// => 82aa771f1183c52f973c798c9243a1c73833ea40961c73e55e12430ec77b69f6
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return 0;
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}
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```
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