如何在ASP.NET核心web API中对文件进行加密和解密

using System.IO;
using System.Security.Cryptography;

byte[] key = new byte[32]; // 256位密钥
using (var rng = RandomNumberGenerator.Create())
{
    rng.GetBytes(key);
}

public byte[] EncryptFile(string filePath, byte[] key)
{
    byte[] encryptedBytes;
    using (Aes aes = Aes.Create())
    {
        aes.Key = key;
        aes.GenerateIV();

        using (var encryptor = aes.CreateEncryptor())
        {
            using (var inputFileStream = File.OpenRead(filePath))
            using (var memoryStream = new MemoryStream())
            using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
            {
                inputFileStream.CopyTo(cryptoStream);
                cryptoStream.FlushFinalBlock();
                encryptedBytes = memoryStream.ToArray();
            }
        }
    }
    return encryptedBytes;
}

public byte[] DecryptFile(byte[] encryptedBytes, byte[] key)
{
    byte[] decryptedBytes;
    using (Aes aes = Aes.Create())
    {
        aes.Key = key;
        aes.GenerateIV();

        using (var decryptor = aes.CreateDecryptor())
        {
            using (var memoryStream = new MemoryStream(encryptedBytes))
            using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
            using (var outputStream = new MemoryStream())
            {
                cryptoStream.CopyTo(outputStream);
                decryptedBytes = outputStream.ToArray();
            }
        }
    }
    return decryptedBytes;
}

[HttpPost]
public IActionResult EncryptFile()
{
    // 从请求中获取文件
    var file = Request.Form.Files[0];

    // 将文件转换为字节数组
    byte[] fileBytes;
    using (var memoryStream = new MemoryStream())
    {
        file.CopyTo(memoryStream);
        fileBytes = memoryStream.ToArray();
    }

    // 加密文件
    byte[] encryptedBytes = EncryptFile(fileBytes, key);

    // 返回加密后的文件
    return File(encryptedBytes, "application/octet-stream", "encrypted_file");
}

[HttpPost]
public IActionResult DecryptFile()
{
    // 从请求中获取加密文件
    var file = Request.Form.Files[0];

    // 将文件转换为字节数组
    byte[] fileBytes;
    using (var memoryStream = new MemoryStream())
    {
        file.CopyTo(memoryStream);
        fileBytes = memoryStream.ToArray();
    }

    // 解密文件
    byte[] decryptedBytes = DecryptFile(fileBytes, key);

    // 返回解密后的文件
    return File(decryptedBytes, "application/octet-stream", "decrypted_file");
}