Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry) { CryptoStream result = null; if ( (entry.Version < ZipConstants.VersionStrongEncryption) || (entry.Flags & (int)GeneralBitFlags.StrongEncryption) == 0) { PkzipClassicManaged classicManaged = new PkzipClassicManaged(); OnKeysRequired(entry.Name); if (HaveKeys == false) { throw new ZipException("No password available for encrypted stream"); } result = new CryptoStream(baseStream, classicManaged.CreateDecryptor(key, null), CryptoStreamMode.Read); CheckClassicPassword(result, entry); } else { throw new ZipException("Decryption method not supported"); } return result; }
Stream CreateAndInitEncryptionStream(Stream baseStream, ZipEntry entry) { CryptoStream result = null; if ( (entry.Version < ZipConstants.VersionStrongEncryption) || (entry.Flags & (int)GeneralBitFlags.StrongEncryption) == 0) { PkzipClassicManaged classicManaged = new PkzipClassicManaged(); OnKeysRequired(entry.Name); if (HaveKeys == false) { throw new ZipException("No password available for encrypted stream"); } // Closing a CryptoStream will close the base stream as well so wrap it in an UncompressedStream // which doesnt do this. result = new CryptoStream(new UncompressedStream(baseStream), classicManaged.CreateEncryptor(key, null), CryptoStreamMode.Write); if ( (entry.Crc < 0) || (entry.Flags & 8) != 0) { WriteEncryptionHeader(result, entry.DosTime << 16); } else { WriteEncryptionHeader(result, entry.Crc); } } return result; }
/// <summary> /// Perform the initial read on an entry which may include /// reading encryption headers and setting up inflation. /// </summary> /// <param name="destination">The destination to fill with data read.</param> /// <param name="offset">The offset to start reading at.</param> /// <param name="count">The maximum number of bytes to read.</param> /// <returns>The actual number of bytes read.</returns> int InitialRead(byte[] destination, int offset, int count) { if ( !entry.CanDecompress ) { throw new ZipException("Library cannot extract this entry. Version required is (" + entry.Version.ToString() + ")"); } // Handle encryption if required. if (entry.IsCrypted) { if (password == null) { throw new ZipException("No password set."); } // Generate and set crypto transform... PkzipClassicManaged managed = new PkzipClassicManaged(); byte[] key = PkzipClassic.GenerateKeys(Encoding.ASCII.GetBytes(password)); inputBuffer.CryptoTransform = managed.CreateDecryptor(key, null); byte[] cryptbuffer = new byte[ZipConstants.CryptoHeaderSize]; inputBuffer.ReadClearTextBuffer(cryptbuffer, 0, ZipConstants.CryptoHeaderSize); if (cryptbuffer[ZipConstants.CryptoHeaderSize - 1] != entry.CryptoCheckValue) { throw new ZipException("Invalid password"); } if (csize >= ZipConstants.CryptoHeaderSize) { csize -= ZipConstants.CryptoHeaderSize; } } else { inputBuffer.CryptoTransform = null; } if ( (method == (int)CompressionMethod.Deflated) && (inputBuffer.Available > 0) ) { inputBuffer.SetInflaterInput(inf); } internalReader = new ReaderDelegate(BodyRead); return BodyRead(destination, offset, count); }