/// <summary>
/// Loads a <see cref="AegisBondArchive"/> from disk. This operation does not unlock the archive.
/// </summary>
/// <param name="fileSettings">Settings for where the archive and related files are stored.</param>
/// <returns>The loaded <see cref="AegisBondArchive"/>.</returns>
public static AegisArchive Load(SecureArchiveFileSettings fileSettings)
{
ArgCheck.IsValid(fileSettings, nameof(fileSettings));
ZipArchive tempSecureArchive = null;
AegisArchive archive = null;
try
{
// Open the secure archive and read the metadata entry.
tempSecureArchive = OpenSecureArchiveFile(fileSettings);
var metadataEntry = tempSecureArchive.GetEntry(AegisConstants.SecureArchiveMetadataEntryName);
if (metadataEntry is null)
{
throw new ArchiveCorruptedException("The secure archive does not contain any internal metadata!");
}
using var metadataReader = new StreamReader(metadataEntry.Open());
var metadataJson = metadataReader.ReadToEnd();
var metadata = JsonSerializer.Deserialize <SecureArchiveMetadata>(metadataJson);
if (metadata is null)
{
throw new ArchiveCorruptedException("Unable to parse the archive internal metadata!");
}
archive = new AegisArchive
{
ArchiveMetadata = metadata,
FileSettings = fileSettings,
SecureArchive = tempSecureArchive,
};
// We've transfered dispose ownership of tempSecureArchive to the archive.
tempSecureArchive = null;
}
finally
{
tempSecureArchive?.Dispose();
}
return(archive);
}
/// <summary>
/// Opens a secure archive (zip) file on disk.
/// </summary>
/// <param name="fileSettings">The <see cref="SecureArchiveFileSettings"/> for the archive to open.</param>
/// <param name="createNewArchive">Indicates whether we expect to be creating a new secure archive.</param>
private static ZipArchive OpenSecureArchiveFile(SecureArchiveFileSettings fileSettings, bool createNewArchive = false)
{
if (createNewArchive)
{
// Create the output directory if it doesn't already exist.
var directoryPath = Path.GetDirectoryName(fileSettings.Path);
if (!string.IsNullOrWhiteSpace(directoryPath) && !Directory.Exists(directoryPath))
{
Directory.CreateDirectory(directoryPath);
}
}
else if (!File.Exists(fileSettings.Path))
{
throw new FileNotFoundException($"No archive file was found at {fileSettings.Path}", fileSettings.Path);
}
return(ZipFile.Open(fileSettings.Path, ZipArchiveMode.Update));
}
/// <summary>
/// Creates a new <see cref="AegisArchive"/> that contains no files.
/// </summary>
/// <param name="fileSettings">Settings for where the archive and related files are stored.</param>
/// <param name="creationParameters">The <see cref="SecureArchiveCreationParameters"/> to use when creating the archive.</param>
/// <returns>A new <see cref="AegisArchive"/> that is opened but not yet persisted to disk.</returns>
public static AegisArchive CreateNew(
SecureArchiveFileSettings fileSettings,
SecureArchiveCreationParameters creationParameters)
{
ArgCheck.IsValid(fileSettings, nameof(fileSettings));
ArgCheck.IsValid(creationParameters, nameof(creationParameters));
var currentTime = DateTimeOffset.UtcNow;
var archiveId = Guid.NewGuid();
ArchiveKey tempArchiveKey = null;
AegisArchive tempArchive = null;
AegisArchive archive = null;
try
{
tempArchiveKey = ArchiveKey.CreateNew(creationParameters.SecuritySettings);
// Derive and authorize the first user key.
var keyDerivationSalt = CryptoHelpers.GetRandomBytes(creationParameters.KeyDerivationSaltSizeInBytes);
var firstUserKeyAuthorization = UserKeyAuthorizationExtensions.CreateNewAuthorization(
creationParameters.FirstKeyAuthorizationParams,
keyDerivationSalt,
tempArchiveKey,
creationParameters.SecuritySettings);
var authCanary = tempArchiveKey.Encrypt(
CryptoHelpers.GetCryptoStrategy(creationParameters.SecuritySettings.EncryptionAlgo),
archiveId.ToByteArray());
var archiveMetadata = new SecureArchiveMetadata
{
Id = archiveId,
SecuritySettings = creationParameters.SecuritySettings,
CreateTime = currentTime,
LastModifiedTime = currentTime,
KeyDerivationSalt = new List <byte>(keyDerivationSalt),
AuthCanary = authCanary,
UserKeyAuthorizations = new List <UserKeyAuthorization> {
firstUserKeyAuthorization
},
};
tempArchive = new AegisArchive
{
ArchiveMetadata = archiveMetadata,
ArchiveKey = tempArchiveKey,
FileSettings = fileSettings,
FileIndex = new FileIndex(),
SecureArchive = OpenSecureArchiveFile(fileSettings, createNewArchive: true),
};
tempArchive.PersistMetadata();
// Transfer the archive reference to the return variable.
archive = tempArchive;
tempArchive = null;
// Dispose ownership of the archive key now belongs to the archive.
tempArchiveKey = null;
}
finally
{
tempArchive?.Dispose();
tempArchiveKey?.Dispose();
}
return(archive);
}