下面是如何默认实现(ASP。NET Framework或ASP。NET Core)工作。它使用带有随机盐的键派生函数来生成散列。盐是KDF输出的一部分。因此，每次你“哈希”相同的密码，你将得到不同的哈希。为了验证散列，输出将被分割回盐和其他部分，并且使用指定的盐再次对密码运行KDF。如果结果与初始输出的其余部分匹配，则验证散列。

散列:

public static string HashPassword(string password)
{
    byte[] salt;
    byte[] buffer2;
    if (password == null)
    {
        throw new ArgumentNullException("password");
    }
    using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, 0x10, 0x3e8))
    {
        salt = bytes.Salt;
        buffer2 = bytes.GetBytes(0x20);
    }
    byte[] dst = new byte[0x31];
    Buffer.BlockCopy(salt, 0, dst, 1, 0x10);
    Buffer.BlockCopy(buffer2, 0, dst, 0x11, 0x20);
    return Convert.ToBase64String(dst);
}

验证:

public static bool VerifyHashedPassword(string hashedPassword, string password)
{
    byte[] buffer4;
    if (hashedPassword == null)
    {
        return false;
    }
    if (password == null)
    {
        throw new ArgumentNullException("password");
    }
    byte[] src = Convert.FromBase64String(hashedPassword);
    if ((src.Length != 0x31) || (src[0] != 0))
    {
        return false;
    }
    byte[] dst = new byte[0x10];
    Buffer.BlockCopy(src, 1, dst, 0, 0x10);
    byte[] buffer3 = new byte[0x20];
    Buffer.BlockCopy(src, 0x11, buffer3, 0, 0x20);
    using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, dst, 0x3e8))
    {
        buffer4 = bytes.GetBytes(0x20);
    }
    return ByteArraysEqual(buffer3, buffer4);
}

对于像我这样的新手来说，这里是带有const的代码和比较byte[]的实际方法。我从stackoverflow得到了所有这些代码，但定义了consts，所以值可以被改变

// 24 = 192 bits
    private const int SaltByteSize = 24;
    private const int HashByteSize = 24;
    private const int HasingIterationsCount = 10101;


    public static string HashPassword(string password)
    {
        // http://stackoverflow.com/questions/19957176/asp-net-identity-password-hashing

        byte[] salt;
        byte[] buffer2;
        if (password == null)
        {
            throw new ArgumentNullException("password");
        }
        using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, SaltByteSize, HasingIterationsCount))
        {
            salt = bytes.Salt;
            buffer2 = bytes.GetBytes(HashByteSize);
        }
        byte[] dst = new byte[(SaltByteSize + HashByteSize) + 1];
        Buffer.BlockCopy(salt, 0, dst, 1, SaltByteSize);
        Buffer.BlockCopy(buffer2, 0, dst, SaltByteSize + 1, HashByteSize);
        return Convert.ToBase64String(dst);
    }

    public static bool VerifyHashedPassword(string hashedPassword, string password)
    {
        byte[] _passwordHashBytes;

        int _arrayLen = (SaltByteSize + HashByteSize) + 1;

        if (hashedPassword == null)
        {
            return false;
        }

        if (password == null)
        {
            throw new ArgumentNullException("password");
        }

        byte[] src = Convert.FromBase64String(hashedPassword);

        if ((src.Length != _arrayLen) || (src[0] != 0))
        {
            return false;
        }

        byte[] _currentSaltBytes = new byte[SaltByteSize];
        Buffer.BlockCopy(src, 1, _currentSaltBytes, 0, SaltByteSize);

        byte[] _currentHashBytes = new byte[HashByteSize];
        Buffer.BlockCopy(src, SaltByteSize + 1, _currentHashBytes, 0, HashByteSize);

        using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, _currentSaltBytes, HasingIterationsCount))
        {
            _passwordHashBytes = bytes.GetBytes(SaltByteSize);
        }

        return AreHashesEqual(_currentHashBytes, _passwordHashBytes);

    }

    private static bool AreHashesEqual(byte[] firstHash, byte[] secondHash)
    {
        int _minHashLength = firstHash.Length <= secondHash.Length ? firstHash.Length : secondHash.Length;
        var xor = firstHash.Length ^ secondHash.Length;
        for (int i = 0; i < _minHashLength; i++)
            xor |= firstHash[i] ^ secondHash[i];
        return 0 == xor;
    }

在您的自定义ApplicationUserManager中，您将PasswordHasher属性设置为包含上述代码的类的名称。

我理解公认的答案，并对其进行了投票，但我认为我应该在这里抛弃我的外行答案…

创建散列

The salt is randomly generated using the function Rfc2898DeriveBytes which generates a hash and a salt. Inputs to Rfc2898DeriveBytes are the password, the size of the salt to generate and the number of hashing iterations to perform. https://msdn.microsoft.com/en-us/library/h83s4e12(v=vs.110).aspx The salt and the hash are then mashed together(salt first followed by the hash) and encoded as a string (so the salt is encoded in the hash). This encoded hash (which contains the salt and hash) is then stored (typically) in the database against the user.

根据散列检查密码

检查用户输入的密码。

盐是从存储的散列密码中提取的。 salt使用重载Rfc2898DeriveBytes对用户输入的密码进行哈希，Rfc2898DeriveBytes接受salt而不是生成一个。https://msdn.microsoft.com/en-us/library/yx129kfs (v = vs.110) . aspx 然后比较存储的哈希和测试哈希。

哈希

在封面下，哈希是使用SHA1哈希函数(https://en.wikipedia.org/wiki/SHA-1)生成的。 这个函数被迭代调用1000次(在默认的Identity实现中)

为什么这是安全的

Random salts means that an attacker can’t use a pre-generated table of hashs to try and break passwords. They would need to generate a hash table for every salt. (Assuming here that the hacker has also compromised your salt) If 2 passwords are identical they will have different hashes. (meaning attackers can’t infer ‘common’ passwords) Iteratively calling SHA1 1000 times means that the attacker also needs to do this. The idea being that unless they have time on a supercomputer they won’t have enough resource to brute force the password from the hash. It would massively slow down the time to generate a hash table for a given salt.

请听安德鲁·萨维尼克的回答 我做了以下更改。 我使用Dapper与一个现有的数据库配置了AspNet身份。

请注意PasswordHasherCompatibilityMode。IdentityV2作品 如果你正在使用AspNet身份认证，那就太好了。尚未测试AspNetCore 的身份。

这是完整类的GitHub Gist。

我写我的类PasswordHasher基于。net6 PasswordHasher文档的最新版本(V3) https://github.com/dotnet/aspnetcore/blob/b56bb17db3ae73ce5a8664a2023a9b9af89499dd/src/Identity/Extensions.Core/src/PasswordHasher.cs

namespace Utilities;

public class PasswordHasher
{
    public const int Pbkdf2Iterations = 1000;


    public static string HashPasswordV3(string password)
    {
        return Convert.ToBase64String(HashPasswordV3(password, RandomNumberGenerator.Create()
            , prf: KeyDerivationPrf.HMACSHA512, iterCount: Pbkdf2Iterations, saltSize: 128 / 8
            , numBytesRequested: 256 / 8));
    }


    public static bool VerifyHashedPasswordV3(string hashedPasswordStr, string password)
    {
        byte[] hashedPassword = Convert.FromBase64String(hashedPasswordStr);
        var iterCount = default(int);
        var prf = default(KeyDerivationPrf);

        try
        {
            // Read header information
            prf = (KeyDerivationPrf)ReadNetworkByteOrder(hashedPassword, 1);
            iterCount = (int)ReadNetworkByteOrder(hashedPassword, 5);
            int saltLength = (int)ReadNetworkByteOrder(hashedPassword, 9);

            // Read the salt: must be >= 128 bits
            if (saltLength < 128 / 8)
            {
                return false;
            }
            byte[] salt = new byte[saltLength];
            Buffer.BlockCopy(hashedPassword, 13, salt, 0, salt.Length);

            // Read the subkey (the rest of the payload): must be >= 128 bits
            int subkeyLength = hashedPassword.Length - 13 - salt.Length;
            if (subkeyLength < 128 / 8)
            {
                return false;
            }
            byte[] expectedSubkey = new byte[subkeyLength];
            Buffer.BlockCopy(hashedPassword, 13 + salt.Length, expectedSubkey, 0, expectedSubkey.Length);

            // Hash the incoming password and verify it
            byte[] actualSubkey = KeyDerivation.Pbkdf2(password, salt, prf, iterCount, subkeyLength);
#if NETSTANDARD2_0 || NETFRAMEWORK
            return ByteArraysEqual(actualSubkey, expectedSubkey);
#elif NETCOREAPP
            return CryptographicOperations.FixedTimeEquals(actualSubkey, expectedSubkey);
#else
#error Update target frameworks
#endif
        }
        catch
        {
            // This should never occur except in the case of a malformed payload, where
            // we might go off the end of the array. Regardless, a malformed payload
            // implies verification failed.
            return false;
        }
    }


    // privates
    private static byte[] HashPasswordV3(string password, RandomNumberGenerator rng, KeyDerivationPrf prf, int iterCount, int saltSize, int numBytesRequested)
    {
        byte[] salt = new byte[saltSize];
        rng.GetBytes(salt);
        byte[] subkey = KeyDerivation.Pbkdf2(password, salt, prf, iterCount, numBytesRequested);
        var outputBytes = new byte[13 + salt.Length + subkey.Length];
        outputBytes[0] = 0x01; // format marker
        WriteNetworkByteOrder(outputBytes, 1, (uint)prf);
        WriteNetworkByteOrder(outputBytes, 5, (uint)iterCount);
        WriteNetworkByteOrder(outputBytes, 9, (uint)saltSize);
        Buffer.BlockCopy(salt, 0, outputBytes, 13, salt.Length);
        Buffer.BlockCopy(subkey, 0, outputBytes, 13 + saltSize, subkey.Length);
        return outputBytes;
    }

    private static void WriteNetworkByteOrder(byte[] buffer, int offset, uint value)
    {
        buffer[offset + 0] = (byte)(value >> 24);
        buffer[offset + 1] = (byte)(value >> 16);
        buffer[offset + 2] = (byte)(value >> 8);
        buffer[offset + 3] = (byte)(value >> 0);
    }

    private static uint ReadNetworkByteOrder(byte[] buffer, int offset)
    {
        return ((uint)(buffer[offset + 0]) << 24)
            | ((uint)(buffer[offset + 1]) << 16)
            | ((uint)(buffer[offset + 2]) << 8)
            | ((uint)(buffer[offset + 3]));
    }

}

在UserController中使用:

namespace WebApi.Controllers.UserController;

[Route("api/[controller]/[action]")]
[ApiController]
public class UserController : ControllerBase
{
    private readonly IUserService _userService;
    public UserController(IUserService userService)
    {
        _userService = userService;
    }


[HttpPost]
public async Task<IActionResult> Register(VmRegister model)
{
    var user = new User
    {
        UserName = model.UserName,
        PasswordHash = PasswordHasher.HashPasswordV3(model.Password),
        FirstName = model.FirstName,
        LastName = model.LastName,
        Mobile = model.Mobile,
        Email = model.Email,
    };
    await _userService.Add(user);
    return StatusCode(201, user.Id);
}


[HttpPost]
public async Task<IActionResult> Login(VmLogin model)
{
    var user = await _userService.GetByUserName(model.UserName);

    if (user is null || !PasswordHasher.VerifyHashedPasswordV3(user.PasswordHash, model.Password))
        throw new Exception("The UserName or Password is wrong.");
    // generate token
    return Ok();
}

}

https://github.com/mammadkoma/WebApi/tree/master/WebApi

因为这些天ASP。NET是开源的，你可以在GitHub上找到它: AspNet。Identity 3.0和AspNet。2.0身份。

评论如下:

/* =======================
 * HASHED PASSWORD FORMATS
 * =======================
 * 
 * Version 2:
 * PBKDF2 with HMAC-SHA1, 128-bit salt, 256-bit subkey, 1000 iterations.
 * (See also: SDL crypto guidelines v5.1, Part III)
 * Format: { 0x00, salt, subkey }
 *
 * Version 3:
 * PBKDF2 with HMAC-SHA256, 128-bit salt, 256-bit subkey, 10000 iterations.
 * Format: { 0x01, prf (UInt32), iter count (UInt32), salt length (UInt32), salt, subkey }
 * (All UInt32s are stored big-endian.)
 */