/// <summary>
/// Write password data with filtering original data. Available filters must be added to instance before this method is called.
/// </summary>
public virtual void WritePasswordToFile(byte[] masterPasswordHash, PasswordFileBody passwordData)
{
if (!PasswordFile.CheckDirectoryWritable(Directory.GetParent(this.Filepath).FullName))
{
throw new IOException();
}
MemoryStream decryptedData = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();
// Apply data filters
FilteredData filteredData = IOFilterProcessor.ApplyFilter(passwordData, this.FilterOrder);
// Convert FilteredData object into MemoryStream
formatter.Serialize(decryptedData, filteredData);
decryptedData.Position = 0;
// Get token
byte[] token = Utility.Get16BytesHash(DateTime.Now);
// Do encryption here
byte[] encryptedBytes = Utility.Encrypt(decryptedData.ToArray(), masterPasswordHash, token);
// Construct header
PasswordHeader header = new PasswordHeader();
header.Token = token;
header.CombinedMasterPasswordHash = Utility.Scramble(masterPasswordHash, token, LocalConfig.MasterPasswordHashedKeySize);
// Write filtered data to the file
using (FileStream fs = new FileStream(this.Filepath, FileMode.Create, FileAccess.Write))
{
// Write header
using (BinaryWriter writer = new BinaryWriter(fs))
{
writer.Write(header.Token); // Write token
writer.Write(header.CombinedMasterPasswordHash); // Write hash
// Write Filtered data which has been encrypted
writer.Write(encryptedBytes);
}
}
}
/// <summary>
/// Check whether password hash is valid for specified password file.
/// </summary>
/// <param name="filePath"></param>
/// <returns></returns>
public static bool ChallengeHashedMasterPassword(string filePath, byte[] challengingPasswordHash)
{
// When password file does not exist, throw an exception.
if (!File.Exists(filePath))
{
throw new FileNotFoundException(filePath);
}
// Parse file header
using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
using (BinaryReader reader = new BinaryReader(fs))
{
PasswordHeader header = new PasswordHeader();
header.Token = reader.ReadBytes(LocalConfig.HeaderTokenSize);
header.CombinedMasterPasswordHash = reader.ReadBytes(LocalConfig.MasterPasswordHashedKeySize);
return CompareHashes(header.CombinedMasterPasswordHash, Utility.Scramble(challengingPasswordHash, header.Token, LocalConfig.MasterPasswordHashedKeySize));
}
}
}
/// <summary>
/// Read password file with removing data filter. Available filters must be added to instance before this method is called.
/// </summary>
/// <exception cref="FileNotFoundException">Password file does not exist</exception>
/// <exception cref="InvalidMasterPasswordException">Master password is invalid</exception>
public virtual PasswordFileBody ReadPasswordFromFile(byte[] masterPasswordHash, PasswordFileBody defaultPasswordFileBody = null)
{
if (masterPasswordHash.Length != LocalConfig.MasterPasswordHashedKeySize)
{
throw new ArgumentException();
}
// When password file does not exist, throw an exception.
if (!File.Exists(this.Filepath))
{
throw new FileNotFoundException(this.Filepath);
}
FilteredData filteredData;
// Parse file header
using (FileStream fs = new FileStream(this.Filepath, FileMode.Open, FileAccess.Read))
{
using (BinaryReader reader = new BinaryReader(fs))
{
PasswordHeader header = new PasswordHeader();
header.Token = reader.ReadBytes(LocalConfig.HeaderTokenSize);
header.CombinedMasterPasswordHash = reader.ReadBytes(LocalConfig.MasterPasswordHashedKeySize);
// Check masterPasswordHash is valid
if (!CheckMasterPasswordHash(header.CombinedMasterPasswordHash, masterPasswordHash, header.Token))
{
throw new InvalidMasterPasswordException();
}
MemoryStream encryptedData = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();
encryptedData = Utility.GetMemoryStream(reader);
encryptedData.Position = 0;
// Do decryption against loaded MemoryStream
byte[] decryptedBytes = Utility.Decrypt(encryptedData.ToArray(), masterPasswordHash, header.Token);
MemoryStream decryptedData = new MemoryStream(decryptedBytes);
decryptedData.Position = 0;
// Get filtered data
filteredData = (FilteredData)formatter.Deserialize(decryptedData);
}
}
// Parse filter data
return (PasswordFileBody)IOFilterProcessor.RemoveFilter(filteredData);
}