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gfd2
Asked:2022-04-15 18:09:12 +0000 UTC2022-04-15 18:09:12 +0000 UTC

使用 Apache 特定的 salted MD5 算法生成密码哈希

  • 772

您需要从 C# 中的登录名和密码中获取此字符串。

test:$apr1$zg40inu2$fb4NUdl7Gj4yfKIwWJFt//

此行包含用户名和密码test。想不通。

c#

1 个回答

  1. Best Answer

    这是一次伟大的冒险，谢谢。为什么 Apache 开发人员这样做并不完全清楚，但可能是为了保护不安全的 MD5。

    文档：

    Apache 特定算法使用随机 32 位盐和密码的各种组合的迭代（1,000 次）MD5 摘要。有关算法的详细信息，请参见 APR 源文件apr_md5.c。

    我通过将源代码转换为 PHP收到了此代码。

    static void Main(string[] args)
{
    string src = "$apr1$zg40inu2$fb4NUdl7Gj4yfKIwWJFt//";
    string[] hashed = src.Split('$');
    string pass = "test";
    string salt = hashed[2];
    Console.WriteLine(src);
    Console.WriteLine(CryptApr1MD5(pass, salt));
    Console.ReadKey();
}

static string CryptApr1MD5(string password, string salt = null)
{
    const string base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    const string outputChars = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    if (salt is null)
    {
        Random rnd = new Random();
        salt = string.Concat(Enumerable.Range(0, 8).Select(_ => outputChars[rnd.Next(0, outputChars.Length)]));
    }

    byte[] saltBytes = Encoding.ASCII.GetBytes(salt);
    byte[] passBytes = Encoding.ASCII.GetBytes(password);

    List<byte> tmp = new List<byte>(Encoding.ASCII.GetBytes($"{password}$apr1${salt}"));
    MD5 md5 = MD5.Create();
    byte[] hashBytes = md5.ComputeHash(Encoding.ASCII.GetBytes(password + salt + password));
    for (int i = password.Length; i > 0; i -= 16) 
        tmp.AddRange(hashBytes.Take(Math.Min(16, i)));
    for (int i = password.Length; i > 0; i >>= 1) 
        tmp.Add((i & 1) == 1 ? (byte)0 : passBytes[0]);
    hashBytes = md5.ComputeHash(tmp.ToArray());
    tmp.Clear();

    for (int i = 0; i < 1000; i++)
    {
        tmp.AddRange((i & 1) == 1 ? passBytes : hashBytes);
        if (i % 3 != 0)
            tmp.AddRange(saltBytes);
        if (i % 7 != 0)
            tmp.AddRange(passBytes);
        tmp.AddRange((i & 1) == 1 ? hashBytes : passBytes);
        hashBytes = md5.ComputeHash(tmp.ToArray());
        tmp.Clear();
    }

    tmp.Add(0);
    tmp.Add(0);
    tmp.Add(hashBytes[11]);
    for (int i = 4; i >= 0; i--)
    {
        tmp.Add(hashBytes[i]);
        tmp.Add(hashBytes[i + 6]);
        tmp.Add(hashBytes[i == 4 ? 5 : i + 12]);
    }

    string result = string.Concat(Convert.ToBase64String(tmp.ToArray()).Skip(2).Reverse().Select(c => outputChars[base64Chars.IndexOf(c)]));

    return $"$apr1${salt}${result}";
}

    控制台输出

    $apr1$zg40inu2$fb4NUdl7Gj4yfKIwWJFt//
$apr1$zg40inu2$fb4NUdl7Gj4yfKIwWJFt//

    替代实现，大约快 20%，需要 C# 8.0。

    static string CryptApr1MD52(string password, string salt = null)
{
    const string base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    const string outputChars = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    const string signature = "$apr1$";

    if (salt is null)
    {
        salt = string.Create(8, new Random(), (span, rnd) =>
        {
            for (int i = 0; i < span.Length; i++)
                span[i] = outputChars[rnd.Next(0, outputChars.Length)];
        });
    }

    byte[] saltBytes = Encoding.ASCII.GetBytes(salt);
    byte[] passBytes = Encoding.ASCII.GetBytes(password);
    byte[] signBytes = Encoding.ASCII.GetBytes(signature);

    using var ms = new MemoryStream();
    MD5 md5 = MD5.Create();
            
    ms.Write(passBytes);
    ms.Write(saltBytes);
    ms.Write(passBytes);
    byte[] hashBytes = md5.ComputeHash(ms.GetBuffer(), 0, (int)ms.Position);
    ms.SetLength(passBytes.Length);

    ms.Write(signBytes);
    ms.Write(saltBytes);
    for (int i = 0; i < passBytes.Length; i += 16)
        ms.Write(hashBytes, 0, Math.Min(passBytes.Length - i, 16));
    for (int i = passBytes.Length; i > 0; i >>= 1)
        ms.WriteByte((i & 1) == 1 ? (byte)0 : passBytes[0]);
    hashBytes = md5.ComputeHash(ms.GetBuffer(), 0, (int)ms.Position);
    ms.SetLength(0);

    for (int i = 0; i < 1000; i++)
    {
        ms.Write((i & 1) == 1 ? passBytes : hashBytes);
        if (i % 3 != 0)
            ms.Write(saltBytes);
        if (i % 7 != 0)
            ms.Write(passBytes);
        ms.Write((i & 1) == 1 ? hashBytes : passBytes);
        hashBytes = md5.ComputeHash(ms.GetBuffer(), 0, (int)ms.Position);
        ms.SetLength(0);
    }

    ms.WriteByte(0);
    ms.WriteByte(0);
    ms.WriteByte(hashBytes[11]);
    for (int i = 4; i >= 0; i--)
    {
        ms.WriteByte(hashBytes[i]);
        ms.WriteByte(hashBytes[i + 6]);
        ms.WriteByte(hashBytes[i == 4 ? 5 : i + 12]);
    }

    return string.Create(37, (ms, salt), (span, t) =>
    {
        signature.AsSpan().CopyTo(span);
        t.salt.AsSpan().CopyTo(span[6..]);
        span[14] = '$';
        ReadOnlySpan<char> buffer = Convert.ToBase64String(t.ms.GetBuffer(), 0, (int)t.ms.Position);
        for (int i = 15; i < span.Length; i++)
            span[i] = outputChars[base64Chars.IndexOf(buffer[^(i - 14)])];
    });
}
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