/// <summary>
/// Decrypts authentication <see cref="Credentials" /> from a
/// byte array using the specified public asymmetric private key and
/// algorithm.
/// </summary>
/// <param name="encrypted">The encrypted credential bytes.</param>
/// <param name="algorithm">The encryption algorithm.</param>
/// <param name="key">The private key.</param>
/// <returns>The decrypted <see cref="Credentials" />.</returns>
/// <remarks>
/// <note>
/// The current implementation supports only the "RSA" provider.
/// </note>
/// </remarks>
/// <exception cref="SecurityException">Thrown if the credentials are corrupt.</exception>
public static Credentials DecryptCredentials(byte[] encrypted, string algorithm, string key)
{
try
{
var decrypted = Decrypt(algorithm, key, encrypted);
using (var ms = new EnhancedMemoryStream(decrypted))
{
string realm;
string account;
string password;
if (ms.ReadInt32() != Crypto.CredentialMagic)
{
throw new SecurityException(Crypto.CorruptCredentialsMsg);
}
realm = ms.ReadString16();
account = ms.ReadString16();
password = ms.ReadString16();
return(new Credentials(realm, account, password));
}
}
catch (Exception e)
{
throw new SecurityException(Crypto.CorruptCredentialsMsg, e);
}
}
public void EnhancedMemoryStream_String()
{
var es = new EnhancedMemoryStream();
es.WriteString16(null);
es.WriteString16("Hello World!");
es.WriteString16(new String('a', 45000));
es.Seek(0, SeekOrigin.Begin);
Assert.IsNull(es.ReadString16());
Assert.AreEqual("Hello World!", es.ReadString16());
Assert.AreEqual(new String('a', 45000), es.ReadString16());
}
/// <summary>
/// Decrypts and deserializes a message from a byte buffer.
/// </summary>
/// <param name="buffer">The buffer.</param>
/// <param name="sharedKey">The shared encryption key.</param>
/// <exception cref="FormatException">Thrown if the buffer does not contain a valid message.</exception>
public DynDnsMessage(byte[] buffer, SymmetricKey sharedKey)
{
try
{
using (var ms = new EnhancedMemoryStream(Crypto.Decrypt(buffer, sharedKey)))
{
if (ms.ReadInt32Le() != Magic)
{
throw new Exception();
}
this.Version = ms.ReadByte();
if (this.Version < FormatVer)
{
throw new FormatException(string.Format("DynDnsMessage version [{0}] is not supported.", this.Version));
}
this.TimeStampUtc = new DateTime(ms.ReadInt64Le());
this.Flags = (DynDnsMessageFlag)ms.ReadInt32Le();
this.HostEntry = new DynDnsHostEntry(ms.ReadString16());
}
}
catch (Exception e)
{
throw new FormatException("Invalid Dynamic DNS message.", e);
}
}
/// <summary>
/// Constructs a key chain by decrypting bytes returned by a previous
/// call to <see cref="Encrypt" />.
/// </summary>
/// <param name="key">The <see cref="SymmetricKey" /> to be used for decrypting.</param>
/// <param name="encrypted">The encrypted key chain.</param>
/// <exception cref="CryptographicException">Thrown if the decrypted key chain is malformed.</exception>
public KeyChain(SymmetricKey key, byte[] encrypted)
{
try
{
using (var ms = new EnhancedMemoryStream(Crypto.Decrypt(encrypted, key)))
{
if (ms.ReadInt32() != Magic)
{
throw new Exception();
}
int count;
count = ms.ReadInt32();
keys = new Dictionary <string, string>(count);
for (int i = 0; i < count; i++)
{
Add(ms.ReadString16());
}
}
}
catch (Exception e)
{
throw new CryptographicException("Key chain is malformed.", e);
}
}
/// <summary>
/// Decrypts the password change parameters encrypted by <see cref="EncryptPasswordChange" />.
/// </summary>
/// <param name="encryptedPasswords">The encryoted password change parameters.</param>
/// <param name="originalPassword">Returns as the original password.</param>
/// <param name="newPassword">Returns as the new password.</param>
/// <remarks>
/// <note>
/// This method is designed to provide a low level of security during development
/// and testing, when the overhead of configuring SSL certificates is not worth
/// the trouble. Do not rely on this method as your only mechanism for securing
/// credentials during transmission in production environments.
/// </note>
/// </remarks>
/// <exception cref="SecurityException">Thrown if the parameters are corrupt.</exception>
public static void DecryptPasswordChange(byte[] encryptedPasswords, out string originalPassword, out string newPassword)
{
try
{
var decrypted = DecryptWithSalt8(encryptedPasswords, credentialsKey);
using (var ms = new EnhancedMemoryStream(decrypted))
{
if (ms.ReadInt32() != CredentialMagic)
{
throw new SecurityException(CorruptCredentialsMsg);
}
originalPassword = ms.ReadString16();
newPassword = ms.ReadString16();
}
}
catch (Exception e)
{
throw new SecurityException(CorruptCredentialsMsg, e);
}
}
public void EnhancedMemoryStream_VerifyBufLength()
{
var es = new EnhancedMemoryStream();
es.WriteInt16(5000);
es.Seek(0, SeekOrigin.Begin);
try
{
es.ReadBytes16();
Assert.Fail();
}
catch
{
}
es.Seek(0, SeekOrigin.Begin);
try
{
es.ReadString16();
Assert.Fail();
}
catch
{
}
es.Seek(0, SeekOrigin.Begin);
es.WriteInt32(500000);
try
{
es.ReadBytes32();
Assert.Fail();
}
catch
{
}
es.Seek(0, SeekOrigin.Begin);
try
{
es.ReadString32();
Assert.Fail();
}
catch
{
}
}
/// <summary>
/// Attempts to acquire the global application lock.
/// </summary>
/// <remarks>
/// <note>
/// <see cref="Release" /> should be called promptly when the
/// application terminates to release the lock.
/// </note>
/// </remarks>
/// <exception cref="GlobalLockException">Thrown when there's a problem acquiring the lock.</exception>
public unsafe void Lock()
{
EnhancedMemoryStream ms;
byte *pMem;
byte[] buf;
Assembly assembly;
string path;
lock (syncLock)
{
if (initLock != null)
{
cLock++; // The lock is already acquired
return;
}
try
{
// Use a global shared memory block to enforce the lock.
assembly = Assembly.GetEntryAssembly();
if (assembly == null)
{
assembly = Assembly.GetCallingAssembly();
}
path = Helper.StripFileScheme(assembly.CodeBase);
ms = new EnhancedMemoryStream(4096);
ms.WriteString16(path);
initLock = new SharedMem();
initLock.Open("LT.Lock." + appName, 4096, SharedMem.OpenMode.CREATE_OPEN);
pMem = initLock.Lock();
if (pMem[0] != 0 || pMem[1] != 0)
{
buf = new byte[initLock.Size];
for (int i = 0; i < buf.Length; i++)
{
buf[i] = pMem[i];
}
ms = new EnhancedMemoryStream(buf);
initLock.Unlock();
initLock.Close();
initLock = null;
throw new GlobalLockException("Global lock is already acquired by [{0}].", ms.ReadString16());
}
buf = ms.ToArray();
for (int i = 0; i < buf.Length; i++)
{
pMem[i] = buf[i];
}
initLock.Unlock();
}
catch (Exception e)
{
throw new GlobalLockException(e);
}
}
cLock++;
}
/// <summary>
/// Decrypts a byte array encrypted using <see cref="Encrypt(string ,byte[],string,int,int,out SymmetricKey)" />.
/// </summary>
/// <param name="rsaKey">The decrypting RSA key as XML or as a secure key container name.</param>
/// <param name="cipherText">The encrypted data.</param>
/// <param name="symmetricKey">Returns as the symmetric encryption algorithm arguments.</param>
/// <returns>The decrypted data.</returns>
/// <exception cref="CryptographicException">Thrown is the encrypted data block is incorrectly formatted.</exception>
/// <remarks>
/// Note that applications should take some care to ensure that the <paramref name="symmetricKey" />
/// value return is disposed so that the symmetric encryption key will be cleared.
/// </remarks>
public static byte[] Decrypt(string rsaKey, byte[] cipherText, out SymmetricKey symmetricKey)
{
EnhancedMemoryStream input = new EnhancedMemoryStream(cipherText);
EnhancedMemoryStream ms = new EnhancedMemoryStream(cipherText.Length);
BlockDecryptor decryptor = null;
byte[] symKey;
byte[] symIV;
string algorithm;
try
{
// Read the header fields
if (input.ReadInt32() != Magic)
{
throw new CryptographicException(BadFormatMsg);
}
if (input.ReadInt32() != 0)
{
throw new CryptographicException("Unsupported secure data format version.");
}
// Decrypt the encryption info
ms.WriteBytesNoLen(AsymmetricCrypto.Decrypt(CryptoAlgorithm.RSA, rsaKey, input.ReadBytes16()));
ms.Position = 0;
algorithm = ms.ReadString16();
symKey = ms.ReadBytes16();
symIV = ms.ReadBytes16();
symmetricKey = new SymmetricKey(algorithm, symKey, symIV);
decryptor = new BlockDecryptor(algorithm, symKey, symIV);
// Decrypt the contents
ms.SetLength(0);
ms.WriteBytesNoLen(decryptor.Decrypt(input.ReadBytes32()));
ms.Position = 0;
if (ms.ReadInt32() != Magic)
{
throw new CryptographicException("Secure data content is corrupt.");
}
ms.Position += 8; // Skip over the salt
return(ms.ReadBytes32());
}
finally
{
if (decryptor != null)
{
decryptor.Dispose();
}
input.Close();
ms.Close();
}
}
