tiku-backend.net/Tiku.Infrastructure/Auth/SmsCodeHashing.cs

using System.Security.Cryptography;
using System.Text;
using Tiku.Domain.Tenancy;

namespace Tiku.Infrastructure.Auth;

public static class SmsCodeHashing
{
    public static string Hash(
        Guid tenantId,
        string phone,
        SmsPurpose purpose,
        string code,
        string pepper)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(pepper);

        var normalized = $"{tenantId:N}:{NormalizePhone(phone)}:{purpose}:{code.Trim()}";
        var hash = HMACSHA256.HashData(
            Encoding.UTF8.GetBytes(pepper),
            Encoding.UTF8.GetBytes(normalized));
        return Convert.ToHexString(hash).ToLowerInvariant();
    }

    public static string HashScope(string value, string pepper)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(pepper);

        var hash = HMACSHA256.HashData(
            Encoding.UTF8.GetBytes(pepper),
            Encoding.UTF8.GetBytes(value.Trim().ToLowerInvariant()));
        return Convert.ToHexString(hash).ToLowerInvariant();
    }

    public static string NormalizePhone(string phone)
    {
        return phone.Trim();
    }
}