edamtoft

public static class HexUtils
{
  private const string HexAlphabet = "0123456789abcdef";

  public static string ToHexString(byte[] bytes)
  {
    return string.Create(bytes.Length * 2, bytes, (chars, buffer) =>
    {
      var charIndex = 0;
      var bufferIndex = 0;

edamtoft

public static class HexUtils
{
  public static string ToHexString(byte[] bytes)
  {
    return string.Create(bytes.Length * 2, bytes, (chars, buffer) =>
    {
      for (var i = 0; i < buffer.Length; i += 2)
      {
        var b = buffer[i / 2];
        chars[i] = GetHexChar(b / 16);

edamtoft

public static class Match
{
  public static Matcher<T, TResult> From<T, TResult>() => new Matcher<T, TResult>();
}

public sealed class Matcher<T, TResult>
{
  public TResult DefaultValue { get; set; }

  public List<(TResult Value, Func<T,bool> Test)> Tests { get; } = new List<(TResult Value, Func<T,bool> Test)>();

edamtoft

public sealed class PasswordHasher : IPasswordHasher
{
  private const int SaltSize = 16; // 128 bit 
  private const int KeySize = 32; // 256 bit

  public PasswordHasher(IOptions<HashingOptions> options)
  {
    Options = options.Value;
  }

edamtoft

public (bool Verified, bool NeedsUpgrade) Check(string hash, string password)
{
  var parts = hash.Split('.', 3);

  if (parts.Length != 3)
  {
    throw new FormatException("Unexpected hash format. " + 
      "Should be formatted as `{iterations}.{salt}.{hash}`");
  }

edamtoft

public string Hash(string password)
{
  using (var algorithm = new Rfc2898DeriveBytes(
    password,
    SaltSize,
    Options.Iterations,
    HashAlgorithmName.SHA256))
  {
    var key = Convert.ToBase64String(algorithm.GetBytes(KeySize));
    var salt = Convert.ToBase64String(algorithm.Salt);

edamtoft

public sealed class PasswordHasher : IPasswordHasher
{
  private const int SaltSize = 16; // 128 bit 
  private const int KeySize = 32; // 256 bit

  public PasswordHasher(IOptions<HashingOptions> options)
  {
    Options = options.Value;
  }

edamtoft

public sealed class HashingOptions
{
  public int Iterations { get; set; } = 10000;
}

edamtoft

public interface IPasswordHasher
{
  string Hash(string password);
  
  (bool Verified, bool NeedsUpgrade) Check(string hash, string password);
}

edamtoft

public interface IRateLimiter
{
  Task<T> RunRateLimited<T>(Func<Task<T>> func);
}