83 lines
2.6 KiB
C#
83 lines
2.6 KiB
C#
using System.Security.Cryptography;
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using System.Text;
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namespace Landmark.OLA.Application.Common.Security
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{
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public static class CookieCryptor
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{
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private static byte[] RandomBytes(int len)
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{
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var b = new byte[len];
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RandomNumberGenerator.Fill(b);
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return b;
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}
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private static byte[] DeriveKey(string pass, byte[] salt, int keyBytes = 32, int iterations = 100_000)
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=> new Rfc2898DeriveBytes(pass, salt, iterations, HashAlgorithmName.SHA256).GetBytes(keyBytes);
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public static string EncryptJwt(string jwt, string key)
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{
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var salt = RandomBytes(32);
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using var aes = Aes.Create();
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aes.KeySize = 256;
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aes.BlockSize = 128;
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aes.Mode = CipherMode.CBC;
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aes.Padding = PaddingMode.PKCS7;
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aes.GenerateIV();
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aes.Key = DeriveKey(key, salt, 32);
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using var ms = new MemoryStream();
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ms.Write(salt, 0, salt.Length);
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ms.Write(aes.IV, 0, aes.IV.Length);
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using (var crypto = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write))
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using (var writer = new StreamWriter(crypto, Encoding.UTF8))
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{
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writer.Write(jwt);
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writer.Flush();
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crypto.FlushFinalBlock();
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}
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return Convert.ToBase64String(ms.ToArray());
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}
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public static string DecryptJwt(string cipherText, string passPhrase)
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{
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var all = Convert.FromBase64String(cipherText);
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var saltLen = 32;
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var ivLen = 16;
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if (all.Length < saltLen + ivLen)
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throw new CryptographicException("Ciphertext too short.");
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var salt = new byte[saltLen];
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Buffer.BlockCopy(all, 0, salt, 0, saltLen);
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var iv = new byte[ivLen];
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Buffer.BlockCopy(all, saltLen, iv, 0, ivLen);
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var cipher = new byte[all.Length - saltLen - ivLen];
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Buffer.BlockCopy(all, saltLen + ivLen, cipher, 0, cipher.Length);
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using var aes = Aes.Create();
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aes.KeySize = 256;
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aes.BlockSize = 128;
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aes.Mode = CipherMode.CBC;
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aes.Padding = PaddingMode.PKCS7;
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aes.Key = DeriveKey(passPhrase, salt, 32);
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aes.IV = iv;
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using var ms = new MemoryStream(cipher);
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using var crypto = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Read);
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using var reader = new StreamReader(crypto, Encoding.UTF8);
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return reader.ReadToEnd();
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}
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}
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}
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