Matthew Gretton-Dann
802adbb317
We're not using OpenSSL3 on Linux so use EVP_DigestInit_Ex and not EVP_DigestInit_Ex2.
60 lines
1.3 KiB
C++
60 lines
1.3 KiB
C++
#include <algorithm>
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#include <array>
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#include <cassert>
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#include <iostream>
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#include <string>
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#include <openssl/evp.h>
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using MD5Digest = std::array<unsigned char, EVP_MAX_MD_SIZE>;
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auto md5(MD5Digest& digest, std::string const& s) -> unsigned int
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{
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EVP_MD const* md{EVP_md5()};
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unsigned int md_len{0};
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EVP_MD_CTX* md_context{EVP_MD_CTX_new()};
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assert(md_context != nullptr);
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EVP_DigestInit_ex(md_context, md, nullptr);
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EVP_DigestUpdate(md_context, s.data(), s.length());
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EVP_DigestFinal_ex(md_context, digest.data(), &md_len);
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return md_len;
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}
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auto get_letter(std::string const& s) -> unsigned
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{
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MD5Digest digest;
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auto len = md5(digest, s);
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assert(len >= 3);
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if (digest[0] == 0 && digest[1] == 0 && (digest[2] & 0xf0) == 0) {
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return digest[2] & 0xf;
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}
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return 16;
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}
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auto main() -> int
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{
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constexpr std::string_view characters{"0123456789abcdef"};
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constexpr unsigned password_length{8};
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std::string result;
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std::string line;
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if (!std::getline(std::cin, line)) {
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std::cerr << "Unable to read from stdin.\n";
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return 1;
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}
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std::uint64_t i{0};
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for (unsigned letter = 0; letter < password_length; ++letter) {
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unsigned c{0};
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while ((c = get_letter(line + std::to_string(i))) == 16) {
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++i;
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}
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result += characters.at(c);
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++i;
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}
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std::cout << "Password: " << result << '\n';
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return 0;
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}
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