internal byte[] DecryptInternal(string password, byte[] encryptionInfo, byte[] encryptedPackage)
{
#region Parse the encryption info data
using (System.IO.MemoryStream ms = new System.IO.MemoryStream(encryptionInfo))
{
System.IO.BinaryReader reader = new System.IO.BinaryReader(ms);
versionMajor = reader.ReadUInt16();
versionMinor = reader.ReadUInt16();
encryptionFlags = (EncryptionFlags)reader.ReadUInt32();
if (encryptionFlags == EncryptionFlags.fExternal)
throw new Exception("An external cryptographic provider is not supported");
// Encryption header
uint headerLength = reader.ReadUInt32();
int skipFlags = reader.ReadInt32(); headerLength -= 4;
sizeExtra = reader.ReadUInt32(); headerLength -= 4;
algId = (AlgId)reader.ReadUInt32(); headerLength -= 4;
algHashId = (AlgHashId)reader.ReadUInt32(); headerLength -= 4;
keySize = reader.ReadInt32(); headerLength -= 4;
providerType = (ProviderType)reader.ReadUInt32(); headerLength -= 4;
reader.ReadUInt32(); headerLength -= 4; // Reserved 1
reader.ReadUInt32(); headerLength -= 4; // Reserved 2
CSPName = System.Text.UnicodeEncoding.Unicode.GetString(reader.ReadBytes((int)headerLength));
// Encryption verifier
saltSize = reader.ReadInt32();
salt = reader.ReadBytes(saltSize);
encryptedVerifier = reader.ReadBytes(0x10);
verifierHashSize = reader.ReadInt32();
encryptedVerifierHash = reader.ReadBytes(providerType == ProviderType.RC4 ? 0x14 : 0x20);
}
#endregion
#region Encryption key generation
Console.WriteLine("Encryption key generation");
byte[] encryptionKey = GeneratePasswordHashUsingSHA1(password);
if (encryptionKey == null) return null;
#endregion
#region Password verification
Console.WriteLine("Password verification");
if (PasswordVerifier(encryptionKey))
{
Console.WriteLine("Password verification succeeded");
}
else
{
Console.WriteLine("Password verification failed");
throw new InvalidPasswordException("The password is not valid");
}
#endregion
#region Decrypt
// First 8 bytes hold the size of the stream
long length = BitConverter.ToInt64(encryptedPackage, 0);
// Decrypt the stream using the generated and validated key
Console.WriteLine("Decrypt the stream using the generated and validated key");
encryptedPackage = AESDecrypt(encryptedPackage, 8, encryptedPackage.Length-8, encryptionKey);
// !! IMPORTANT !! Make sure the final array is the correct size
// Failure to do this will cause an error when the decrypted stream
// is opened by the System.IO.Packaging.Package.Open() method.
byte[] result = encryptedPackage;
if (encryptedPackage.Length > length)
{
result = new byte[length];
Array.Copy(encryptedPackage, result, result.Length);
}
//using (System.IO.FileStream fs = new System.IO.FileStream(@"c:\x.zip", System.IO.FileMode.Create))
//{
// fs.Write(result, 0, result.Length);
//}
return result;
#endregion
}
internal byte[] DecryptInternal(string password, byte[] encryptionInfo, byte[] encryptedPackage)
{
#region Parse the encryption info data
using (System.IO.MemoryStream ms = new System.IO.MemoryStream(encryptionInfo))
{
System.IO.BinaryReader reader = new System.IO.BinaryReader(ms);
versionMajor = reader.ReadUInt16();
versionMinor = reader.ReadUInt16();
encryptionFlags = (EncryptionFlags)reader.ReadUInt32();
if (encryptionFlags == EncryptionFlags.fExternal)
{
throw new Exception("An external cryptographic provider is not supported");
}
// Encryption header
uint headerLength = reader.ReadUInt32();
int skipFlags = reader.ReadInt32(); headerLength -= 4;
sizeExtra = reader.ReadUInt32(); headerLength -= 4;
algId = (AlgId)reader.ReadUInt32(); headerLength -= 4;
algHashId = (AlgHashId)reader.ReadUInt32(); headerLength -= 4;
keySize = reader.ReadInt32(); headerLength -= 4;
providerType = (ProviderType)reader.ReadUInt32(); headerLength -= 4;
reader.ReadUInt32(); headerLength -= 4; // Reserved 1
reader.ReadUInt32(); headerLength -= 4; // Reserved 2
CSPName = System.Text.UnicodeEncoding.Unicode.GetString(reader.ReadBytes((int)headerLength));
// Encryption verifier
saltSize = reader.ReadInt32();
salt = reader.ReadBytes(saltSize);
encryptedVerifier = reader.ReadBytes(0x10);
verifierHashSize = reader.ReadInt32();
encryptedVerifierHash = reader.ReadBytes(providerType == ProviderType.RC4 ? 0x14 : 0x20);
}
#endregion
#region Encryption key generation
Console.WriteLine("Encryption key generation");
byte[] encryptionKey = GeneratePasswordHashUsingSHA1(password);
if (encryptionKey == null)
{
return(null);
}
#endregion
#region Password verification
Console.WriteLine("Password verification");
if (PasswordVerifier(encryptionKey))
{
Console.WriteLine("Password verification succeeded");
}
else
{
Console.WriteLine("Password verification failed");
throw new InvalidPasswordException("The password is not valid");
}
#endregion
#region Decrypt
// First 8 bytes hold the size of the stream
long length = BitConverter.ToInt64(encryptedPackage, 0);
// Decrypt the stream using the generated and validated key
Console.WriteLine("Decrypt the stream using the generated and validated key");
encryptedPackage = AESDecrypt(encryptedPackage, 8, encryptedPackage.Length - 8, encryptionKey);
// !! IMPORTANT !! Make sure the final array is the correct size
// Failure to do this will cause an error when the decrypted stream
// is opened by the System.IO.Packaging.Package.Open() method.
byte[] result = encryptedPackage;
if (encryptedPackage.Length > length)
{
result = new byte[length];
Array.Copy(encryptedPackage, result, result.Length);
}
//using (System.IO.FileStream fs = new System.IO.FileStream(@"c:\x.zip", System.IO.FileMode.Create))
//{
// fs.Write(result, 0, result.Length);
//}
return(result);
#endregion
}
