我有一个关于RSA和AES加密算法的混合实现的内存使用问题。我编写了一个简单的控制台程序（.net核心和C＃8.0 beta），该程序生成一个随机证书并加密/解密文件。执行时间似乎还可以。
以1000次迭代测量的时间
问题似乎出在内存使用上。有了230 KB的文件，程序占用了约20 MB的内存。对于28 MB的文件，程序使用约490 MB。 92 MB的文件最多可增加2 GB，并使用约1.8 GB的内存。
这些数字是否被视为“正常”用法，或者我的代码有问题吗？
这是我对AES加密的实现
static byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
{
// Salt not modified for sample
byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using MemoryStream ms = new MemoryStream();
using RijndaelManaged AES = new RijndaelManaged();
AES.KeySize = 256;
AES.BlockSize = 128;
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using ICryptoTransform csTf = AES.CreateEncryptor();
using CryptoStream cs = new CryptoStream(ms, csTf, CryptoStreamMode.Write);
cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
cs.Close();
return ms.ToArray();
}
static byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
{
// Salt not modified for sample
byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using MemoryStream ms = new MemoryStream();
using RijndaelManaged AES = new RijndaelManaged();
AES.KeySize = 256;
AES.BlockSize = 128;
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using ICryptoTransform csTf = AES.CreateDecryptor();
using CryptoStream cs = new CryptoStream(ms, csTf, CryptoStreamMode.Write);
cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
cs.Close();
return ms.ToArray();
}
static string EncryptString(string text, string password)
{
byte[] baEncrypted = new byte[GetSaltLength() + Encoding.UTF8.GetByteCount(text)];
Array.Copy(GetRandomBytes(), 0, baEncrypted, 0, GetSaltLength());
Array.Copy(Encoding.UTF8.GetBytes(text), 0, baEncrypted, GetSaltLength(), Encoding.UTF8.GetByteCount(text));
return Convert.ToBase64String(AES_Encrypt(baEncrypted, SHA256Managed.Create().ComputeHash(Encoding.UTF8.GetBytes(password))));
}
static string DecryptString(string text, string password)
{
byte[] baDecrypted = AES_Decrypt(Convert.FromBase64String(text), SHA256Managed.Create().ComputeHash(Encoding.UTF8.GetBytes(password)));
byte[] baResult = new byte[baDecrypted.Length - GetSaltLength()];
Array.Copy(baDecrypted, GetSaltLength(), baResult, 0, baResult.Length);
return Encoding.UTF8.GetString(baResult);
}
static byte[] GetRandomBytes()
{
byte[] ba = new byte[GetSaltLength()];
RNGCryptoServiceProvider.Create().GetBytes(ba);
return ba;
}
static int GetSaltLength()
{
return 8;
}
调用方法并重复调用
static void Main(string[] args)
{
CertificateRequest certificateRequest = new CertificateRequest("cn=random_cert", RSA.Create(4096), HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
X509Certificate2 certificate = certificateRequest.CreateSelfSigned(DateTimeOffset.Now, DateTimeOffset.Now.AddYears(2));
String data = File.ReadAllText(@"PATH TO FILE");
Int64 AESenc, RSAenc, AESdec, RSAdec;
List<Int64> aesEncTime = new List<Int64>();
List<Int64> aesDecTime = new List<Int64>();
List<Int64> rsaEncTime = new List<Int64>();
List<Int64> rsaDecTime = new List<Int64>();
for (int i = 0; i < 1000; i++)
{
encryptData(ref certificate, ref data, out AESenc, out RSAenc, out AESdec, out RSAdec);
aesEncTime.Add(AESenc);
aesDecTime.Add(AESdec);
rsaEncTime.Add(RSAenc);
rsaDecTime.Add(RSAdec);
Console.Clear();
Console.WriteLine($"data.Length:\t{data.Length:n0} b");
Console.WriteLine($"UTF8 Bytes:\t{Encoding.UTF8.GetByteCount(data):n0} b");
Console.WriteLine($"Loop:\t\t{i + 1}");
Console.WriteLine("---------------------------------------------------------");
Console.WriteLine($"|AES Enc|Avg: {aesEncTime.Average():0000.00} ms|Max: {aesEncTime.Max():0000.00} ms|Min: {aesEncTime.Min():0000.00} ms|");
Console.WriteLine("|-------|---------------|---------------|---------------|");
Console.WriteLine($"|AES Dec|Avg: {aesDecTime.Average():0000.00} ms|Max: {aesDecTime.Max():0000.00} ms|Min: {aesDecTime.Min():0000.00} ms|");
Console.WriteLine("|-------|---------------|---------------|---------------|");
Console.WriteLine($"|RSA Enc|Avg: {rsaEncTime.Average():0000.00} ms|Max: {rsaEncTime.Max():0000.00} ms|Min: {rsaEncTime.Min():0000.00} ms|");
Console.WriteLine("|-------|---------------|---------------|---------------|");
Console.WriteLine($"|RSA Dec|Avg: {rsaDecTime.Average():0000.00} ms|Max: {rsaDecTime.Max():0000.00} ms|Min: {rsaDecTime.Min():0000.00} ms|");
Console.WriteLine("---------------------------------------------------------");
// Moving GC.Collect outside of the for-loop increases the memory usage
GC.Collect();
}
Console.ReadKey();
}
static void encryptData(ref X509Certificate2 certificate, ref String data, out Int64 AESenc, out Int64 RSAenc, out Int64 AESdec, out Int64 RSAdec)
{
Stopwatch stopwatch = new Stopwatch();
String hash = getSha256(ref data);
stopwatch.Start();
String encryptedData = EncryptString(data, hash);
stopwatch.Stop();
AESenc = stopwatch.ElapsedMilliseconds;
stopwatch.Restart();
String encryptedKey = Convert.ToBase64String(certificate.GetRSAPublicKey().Encrypt(Encoding.UTF8.GetBytes(hash), RSAEncryptionPadding.Pkcs1));
stopwatch.Stop();
RSAenc = stopwatch.ElapsedMilliseconds;
stopwatch.Restart();
String decryptedKey = Encoding.UTF8.GetString(certificate.GetRSAPrivateKey().Decrypt(Convert.FromBase64String(encryptedKey), RSAEncryptionPadding.Pkcs1));
stopwatch.Stop();
RSAdec = stopwatch.ElapsedMilliseconds;
stopwatch.Restart();
String decryptedData = DecryptString(encryptedData, decryptedKey);
stopwatch.Stop();
encryptedData = null;
decryptedData = null;
AESdec = stopwatch.ElapsedMilliseconds;
}
static String getSha256(ref String value)
{
String hash = String.Empty;
Byte[] data = Encoding.UTF8.GetBytes(value);
using SHA256Managed sHA256Managed = new SHA256Managed();
Byte[] hashData = sHA256Managed.ComputeHash(data);
foreach (Byte item in hashData)
{
hash += $"{item:x2}";
}
return hash;
}
可以在没有任何外部资源（不包括要加密的文件）的情况下执行代码。
答案 0 :(得分：0)
您可以通过从FileStream读取数据来将数据流式传输到固定大小的缓冲区中，然后使用CryptoStream通过在文件中放入FileStream在文件中创建密文。而不是MemoryStream来输出。
要解密，请在CryptoStream前面创建一个FileStream以进行读取，然后将缓冲区中的数据写入FileStream以进行写入。
如果您有用于明文或密文的字节数组，或者您使用的是MemoryStream，则说明这样做是错误的。