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// SPDX-FileCopyrightText: 2026 Progmasoft <support@progmasoft.com>
// SPDX-License-Identifier: AGPL-3.0-or-later WITH AdditionRef-Progmasoft-Patent-Grant-1.1
namespace Progmasoft.Progmaweb.Api.Accounts;
/// <summary>Rules for passwords.</summary>
/// <remarks>
/// Only length is constrained, so long passphrases are welcome. The upper bound keeps hashing cost bounded for a
/// request that an anonymous caller can send.
/// </remarks>
internal static class PasswordPolicy
{
/// <summary>Fewest characters a password may have.</summary>
public const int MinimumLength = 12;
/// <summary>Most characters a password may have.</summary>
public const int MaximumLength = 256;
/// <summary>Validates a new password.</summary>
/// <param name="password">The password in plain text.</param>
/// <param name="error">Message for the user when the password is refused; empty otherwise.</param>
/// <returns><see langword="true"/> when the password may be used.</returns>
public static bool TryValidate(string? password, out string error)
{
if (password is null || password.Length < MinimumLength)
{
error = $"Passwords must contain at least {MinimumLength} characters.";
return false;
}
if (password.Length > MaximumLength)
{
error = $"Passwords cannot exceed {MaximumLength} characters.";
return false;
}
if (password.Contains('\0'))
{
error = "Passwords cannot contain a null character.";
return false;
}
error = string.Empty;
return true;
}
}
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