37 lines
1.0 KiB
C#
37 lines
1.0 KiB
C#
using System.Security.Cryptography;
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using System.Text;
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namespace backend.Devices;
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public class DeviceTokenService
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{
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public (string Plaintext, string Hash) Generate()
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{
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Span<byte> bytes = stackalloc byte[32];
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RandomNumberGenerator.Fill(bytes);
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var plaintext = Base64UrlEncode(bytes);
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return (plaintext, Hash(plaintext));
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}
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public string Hash(string plaintext)
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{
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Span<byte> hash = stackalloc byte[32];
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SHA256.HashData(Encoding.UTF8.GetBytes(plaintext), hash);
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return Convert.ToHexString(hash);
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}
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public bool Verify(string plaintext, string expectedHash)
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{
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var actual = Hash(plaintext);
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return CryptographicOperations.FixedTimeEquals(
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Encoding.UTF8.GetBytes(actual),
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Encoding.UTF8.GetBytes(expectedHash));
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}
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private static string Base64UrlEncode(ReadOnlySpan<byte> bytes)
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=> Convert.ToBase64String(bytes)
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.TrimEnd('=')
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.Replace('+', '-')
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.Replace('/', '_');
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}
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