/// <summary>
/// Returns document.
/// </summary>
/// <param name="stream">Stream.</param>
/// <param name="password">Password.</param>
/// <exception cref="FormatException">Cannot parse document.</exception>
public static BimilDocument Open(Stream stream, string password)
{
try {
using (var timer = new Medo.Diagnostics.LifetimeWatch("Open")) {
var doc = new BimilDocument();
var salt = new byte[16];
stream.Read(salt, 0, 16);
doc.PasswordSalt = salt;
var deriveBytes = new Rfc2898DeriveBytes(UTF8Encoding.UTF8.GetBytes(password), doc.PasswordSalt, 4096);
doc.Crypto.Key = deriveBytes.GetBytes(16);
doc.Crypto.IV = deriveBytes.GetBytes(16);
var encBuffer = new byte[stream.Length - 16];
stream.Read(encBuffer, 0, encBuffer.Length);
byte[] decBuffer;
using (var dec = doc.Crypto.CreateDecryptor()) {
decBuffer = dec.TransformFinalBlock(encBuffer, 0, encBuffer.Length);
}
if ((decBuffer[0] == 0x41) && (decBuffer[1] == 0x31) && (decBuffer[2] == 0x32) && (decBuffer[3] == 0x38))
{
if ((decBuffer[decBuffer.Length - 4] != 0x41) || (decBuffer[decBuffer.Length - 3] != 0x31) || (decBuffer[decBuffer.Length - 2] != 0x32) || (decBuffer[decBuffer.Length - 1] != 0x38))
{
throw new FormatException("Invalid secondary identifier.");
}
doc.Id = "A128";
}
else
{
throw new FormatException("Invalid primary identifier.");
}
var currOffset = 4;
while (currOffset < (decBuffer.Length - 4))
{
var itemLen = GetInt32(decBuffer, currOffset);
var item = BimilItem.Parse(doc, decBuffer, currOffset + 4, itemLen);
doc.Items.Add(item);
currOffset += 4 + itemLen;
}
return(doc);
}
} catch (CryptographicException ex) {
throw new FormatException("Cannot parse document.", ex);
} catch (OverflowException ex) {
throw new FormatException("Cannot parse document.", ex);
} catch (SecurityException ex) {
throw new FormatException("Cannot parse document.", ex);
}
}
/// <summary>
/// Saves current document to stream.
/// </summary>
/// <param name="stream">Stream.</param>
public void Save(Stream stream)
{
using (var timer = new Medo.Diagnostics.LifetimeWatch("Save")) {
stream.Write(this.PasswordSalt, 0, this.PasswordSalt.Length);
var buffer = new List <byte>(65536);
buffer.AddRange(new byte[] { 0x41, 0x31, 0x32, 0x38 });
foreach (var item in this.Items)
{
var bytes = item.GetBytes();
buffer.AddRange(GetInt32Bytes(bytes.Length));
buffer.AddRange(bytes);
}
buffer.AddRange(new byte[] { 0x41, 0x31, 0x32, 0x38 });
byte[] encBuffer;
using (var enc = this.Crypto.CreateEncryptor()) {
encBuffer = enc.TransformFinalBlock(buffer.ToArray(), 0, buffer.Count);
}
stream.Write(encBuffer, 0, encBuffer.Length);
}
}
