예제 #1
0
        public static void DecryptStream(Stream fin, Stream fout, string password, WrapProgressCallBack callback)
        {
            int size = (int)fin.Length;              // the size of the file for progress notification

            byte[] bytes    = new byte[BUFFER_SIZE]; // byte buffer
            int    read     = -1;                    // the amount of bytes read from the stream
            int    value    = 0;
            int    outValue = 0;                     // the amount of bytes written out

            // read off the IV and Salt
            byte[] IV = new byte[16];
            fin.Read(IV, 0, 16);

            byte[] salt = new byte[16];
            fin.Read(salt, 0, 16);

            // create the crypting stream
            SymmetricAlgorithm sma = FileWrapHelper.CreateRijndael(password, salt);

            sma.IV = IV;

            value = 32;      // the value for the progress
            long lSize = -1; // the size stored in the input stream

            // create the hashing object, so that we can verify the file
            HashAlgorithm hasher = SHA256.Create();

            // create the cryptostreams that will process the file
            using (CryptoStream cin = new CryptoStream(fin, sma.CreateDecryptor(), CryptoStreamMode.Read),
                   chash = new CryptoStream(Stream.Null, hasher, CryptoStreamMode.Write))
            {
                // read size from file
                BinaryReader br = new BinaryReader(cin);
                lSize = br.ReadInt64();

                ulong tag = br.ReadUInt64();
                if (FC_TAG != tag)
                {
                    throw new FileWrapException("File Corrupted!");
                }

                //determine number of reads to process on the file
                long numReads = lSize / BUFFER_SIZE;

                // determine what is left of the file, after numReads
                long slack = (long)lSize % BUFFER_SIZE;

                // read the buffer_sized chunks
                for (int i = 0; i < numReads; ++i)
                {
                    read = cin.Read(bytes, 0, bytes.Length);
                    fout.Write(bytes, 0, read);
                    chash.Write(bytes, 0, read);
                    value    += read;
                    outValue += read;
                    if (callback != null)
                    {
                        callback(0, size, value);
                    }
                }

                // now read the slack
                if (slack > 0)
                {
                    read = cin.Read(bytes, 0, (int)slack);
                    fout.Write(bytes, 0, read);
                    chash.Write(bytes, 0, read);
                    value    += read;
                    outValue += read;
                    if (callback != null)
                    {
                        callback(0, size, value);
                    }
                }
                // flush and close the hashing stream
                chash.Flush();
                chash.Close();

                // flush and close the output file
                fout.Flush();
                fout.Close();

                // read the current hash value
                byte[] curHash = hasher.Hash;

                // get and compare the current and old hash values
                byte[] oldHash = new byte[hasher.HashSize / 8];
                read = cin.Read(oldHash, 0, oldHash.Length);
                if ((oldHash.Length != read) || (!CheckByteArrays(oldHash, curHash)))
                {
                    throw new FileWrapException("File Corrupted!");
                }
            }

            // make sure the written and stored size are equal
            if (outValue != lSize)
            {
                throw new FileWrapException("File Sizes don't match!");
            }
        }
예제 #2
0
 /// <summary>
 /// takes an input file and decrypts it to the output file
 /// </summary>
 /// <param name="inFile">the file to decrypt</param>
 /// <param name="outFile">the to write the decrypted data to</param>
 /// <param name="password">the password used as the key</param>
 /// <param name="callback">the method to call to notify of progress</param>
 public static void DecryptFile(string inFile, string outFile, string password, WrapProgressCallBack callback)
 {
     using (FileStream fin = File.OpenRead(inFile), fout = File.OpenWrite(outFile))
     {
         DecryptStream(fin, fout, password, callback);
     }
 }
예제 #3
0
        public static void EncryptStream(Stream fin, Stream fout, string password, WrapProgressCallBack callback)
        {
            long lSize = fin.Length;              // the size of the input file for storing
            int  size  = (int)lSize;              // the size of the input file for progress

            byte[] bytes = new byte[BUFFER_SIZE]; // the buffer
            int    read  = -1;                    // the amount of bytes read from the input file
            int    value = 0;                     // the amount overall read from the input file for progress

            // generate IV and Salt
            byte[] IV   = GenerateRandomBytes(16);
            byte[] salt = GenerateRandomBytes(16);

            // create the crypting object
            SymmetricAlgorithm sma = FileWrapHelper.CreateRijndael(password, salt);

            sma.IV = IV;

            // write the IV and salt to the beginning of the file
            fout.Write(IV, 0, IV.Length);
            fout.Write(salt, 0, salt.Length);

            // create the hashing and crypto streams
            HashAlgorithm hasher = SHA256.Create();

            using (CryptoStream cout = new CryptoStream(fout, sma.CreateEncryptor(), CryptoStreamMode.Write),
                   chash = new CryptoStream(Stream.Null, hasher, CryptoStreamMode.Write))
            {
                // write the size of the file to the output file
                BinaryWriter bw = new BinaryWriter(cout);
                bw.Write(lSize);

                // write the file cryptor tag to the file
                bw.Write(FC_TAG);

                // read and the write the bytes to the crypto stream in BUFFER_SIZEd chunks
                while ((read = fin.Read(bytes, 0, bytes.Length)) != 0)
                {
                    cout.Write(bytes, 0, read);
                    chash.Write(bytes, 0, read);
                    value += read;
                    if (callback != null)
                    {
                        callback(0, size, value);
                    }
                }
                // flush and close the hashing object
                chash.Flush();
                chash.Close();

                // read the hash
                byte[] hash = hasher.Hash;

                // write the hash to the end of the file
                cout.Write(hash, 0, hash.Length);

                // flush and close the cryptostream
                cout.Flush();
                cout.Close();
                cout.Dispose();
            }
        }