(C#) Streaming Encryption

Encrypt and decrypt using a stream.

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// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Chilkat.Crypt2 crypt = new Chilkat.Crypt2();

// Setup encryption using the chacha20 algorithm...
crypt.CryptAlgorithm = "chacha20";
crypt.KeyLength = 256;
crypt.EncodingMode = "hex";
string ivHex = "000000000000000000000002";
crypt.SetEncodedIV(ivHex,"hex");
crypt.InitialCount = 42;
string keyHex = "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0";
crypt.SetEncodedKey(keyHex,"hex");

string plainText = "The quick brown fox jumped over the lazy dog.\r\n";

Chilkat.Stream stream = new Chilkat.Stream();

// We'll save the encrypted output in eStrings to demonstrate streaming decryption next.
Chilkat.StringArray eStrings = new Chilkat.StringArray();

// Start a background task that will encrypt a stream.
Chilkat.Task task = crypt.EncryptStreamAsync(stream);
bool success = task.Run();

// Write plainText to the stream, and read chacha20 encrypted text..
string cipherText;
int i;
for (i = 1; i <= 10; i++) {
    // Note: An encryption algorithm's block size will cause buffering,
    // and therefore not every loop iteration will produce output.
    success = stream.WriteString(plainText);
    if (stream.DataAvailable == true) {
        cipherText = stream.ReadBytesENC("hex");
        Debug.WriteLine(cipherText);
        success = eStrings.Append(cipherText);
    }

}

// Tell the background task that the stream has ended.
success = stream.WriteClose();

// Let's make sure the background task finished.
// It should already be the case that the task is finished.
while ((task.Finished != true)) {
    task.SleepMs(20);
}

// Get any remaining data available from the stream.
if (stream.DataAvailable == true) {
    cipherText = stream.ReadBytesENC("hex");
    Debug.WriteLine(cipherText);
    success = eStrings.Append(cipherText);
}

if (task.TaskSuccess != true) {
    Debug.WriteLine("async encryption failed:");
    Debug.WriteLine(task.ResultErrorText);
    success = false;
}

Debug.WriteLine("-- encrypt finished --");

// Now decrypt to return the original.

// Reset the stream object so it can be used again.
stream.Reset();

// Start a background task that will decrypt a stream.
task = crypt.DecryptStreamAsync(stream);
success = task.Run();

int n = eStrings.Count;
for (i = 0; i <= n - 1; i++) {
    success = stream.WriteBytesENC(eStrings.GetString(i),"hex");
    if (stream.DataAvailable == true) {
        plainText = stream.ReadString();
        Debug.WriteLine(plainText);
    }

}

// Tell the background task that the stream has ended.
success = stream.WriteClose();

// Let's make sure the background task finished.
// It should already be the case that the task is finished.
while ((task.Finished != true)) {
    task.SleepMs(20);
}

// Get any remaining data available from the stream.
if (stream.DataAvailable == true) {
    plainText = stream.ReadString();
    Debug.WriteLine(plainText);
}

if (task.TaskSuccess != true) {
    Debug.WriteLine("async decryption failed:");
    Debug.WriteLine(task.ResultErrorText);
    success = false;
}

Debug.WriteLine("-- decrypt finished --");