55 lines
1.8 KiB
C#
55 lines
1.8 KiB
C#
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using System;
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using System.IO;
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using System.Security.Cryptography;
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namespace PCL.Core.Utils.Encryption
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{
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[Obsolete("Do not use this AES mode for Encryption")]
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public sealed class AesCbcProvider : IEncryptionProvider
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{
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public static AesCbcProvider Instance { get; } = new();
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private const int SaltSize = 32;
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private const int IvSize = 16;
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public byte[] Decrypt(ReadOnlySpan<byte> data, ReadOnlySpan<byte> key)
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{
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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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var salt = data[..SaltSize];
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var iv = data[SaltSize..(SaltSize + IvSize)];
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aes.IV = iv.ToArray();
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if (data.Length < salt.Length + iv.Length)
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{
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throw new ArgumentException("AES-CBC: Can not decrypt data, the encrypted data is broken");
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}
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#pragma warning disable SYSLIB0041
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using (var deriveBytes = new Rfc2898DeriveBytes(key.ToArray(), salt.ToArray(), 1000))
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{
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aes.Key = deriveBytes.GetBytes(aes.KeySize / 8);
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}
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#pragma warning restore SYSLIB0041
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using var ret = new MemoryStream();
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using var ms = new MemoryStream(data[(SaltSize + IvSize)..].ToArray());
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using var cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Read);
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cs.CopyTo(ret);
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return ret.ToArray();
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}
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public byte[] Encrypt(ReadOnlySpan<byte> data, ReadOnlySpan<byte> key)
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{
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throw new NotSupportedException("You should no longer use AES-CBC as your encryption method");
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}
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public bool IsSupported { get => false; }
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}
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}
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