738 lines
26 KiB
C#
738 lines
26 KiB
C#
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#region PDFsharp - A .NET library for processing PDF
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//
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// Authors:
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// Stefan Lange
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//
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// Copyright (c) 2005-2017 empira Software GmbH, Cologne Area (Germany)
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//
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// http://www.pdfsharp.com
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// http://sourceforge.net/projects/pdfsharp
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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#endregion
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using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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using PdfSharp.Pdf;
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using PdfSharp.Pdf.IO;
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using PdfSharp.Pdf.Advanced;
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using PdfSharp.Pdf.Internal;
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#if !NETFX_CORE && !UWP
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using System.Security.Cryptography;
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#endif
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#pragma warning disable 0169
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#pragma warning disable 0649
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namespace PdfSharp.Pdf.Security
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{
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/// <summary>
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/// Represents the standard PDF security handler.
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/// </summary>
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public sealed class PdfStandardSecurityHandler : PdfSecurityHandler
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{
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internal PdfStandardSecurityHandler(PdfDocument document)
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: base(document)
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{ }
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internal PdfStandardSecurityHandler(PdfDictionary dict)
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: base(dict)
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{ }
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/// <summary>
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/// Sets the user password of the document. Setting a password automatically sets the
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/// PdfDocumentSecurityLevel to PdfDocumentSecurityLevel.Encrypted128Bit if its current
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/// value is PdfDocumentSecurityLevel.None.
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/// </summary>
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public string UserPassword
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{
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set
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{
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if (_document._securitySettings.DocumentSecurityLevel == PdfDocumentSecurityLevel.None)
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_document._securitySettings.DocumentSecurityLevel = PdfDocumentSecurityLevel.Encrypted128Bit;
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_userPassword = value;
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}
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}
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internal string _userPassword;
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/// <summary>
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/// Sets the owner password of the document. Setting a password automatically sets the
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/// PdfDocumentSecurityLevel to PdfDocumentSecurityLevel.Encrypted128Bit if its current
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/// value is PdfDocumentSecurityLevel.None.
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/// </summary>
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public string OwnerPassword
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{
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set
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{
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if (_document._securitySettings.DocumentSecurityLevel == PdfDocumentSecurityLevel.None)
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_document._securitySettings.DocumentSecurityLevel = PdfDocumentSecurityLevel.Encrypted128Bit;
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_ownerPassword = value;
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}
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}
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internal string _ownerPassword;
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/// <summary>
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/// Gets or sets the user access permission represented as an integer in the P key.
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/// </summary>
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internal PdfUserAccessPermission Permission
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{
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get
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{
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PdfUserAccessPermission permission = (PdfUserAccessPermission)Elements.GetInteger(Keys.P);
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if ((int)permission == 0)
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permission = PdfUserAccessPermission.PermitAll;
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return permission;
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}
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set { Elements.SetInteger(Keys.P, (int)value); }
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}
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/// <summary>
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/// Encrypts the whole document.
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/// </summary>
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public void EncryptDocument()
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{
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foreach (PdfReference iref in _document._irefTable.AllReferences)
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{
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if (!ReferenceEquals(iref.Value, this))
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EncryptObject(iref.Value);
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}
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}
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/// <summary>
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/// Encrypts an indirect object.
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/// </summary>
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internal void EncryptObject(PdfObject value)
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{
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Debug.Assert(value.Reference != null);
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SetHashKey(value.ObjectID);
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#if DEBUG
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if (value.ObjectID.ObjectNumber == 10)
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GetType();
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#endif
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PdfDictionary dict;
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PdfArray array;
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PdfStringObject str;
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if ((dict = value as PdfDictionary) != null)
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EncryptDictionary(dict);
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else if ((array = value as PdfArray) != null)
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EncryptArray(array);
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else if ((str = value as PdfStringObject) != null)
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{
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if (str.Length != 0)
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{
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byte[] bytes = str.EncryptionValue;
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PrepareKey();
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EncryptRC4(bytes);
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str.EncryptionValue = bytes;
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}
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}
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}
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/// <summary>
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/// Encrypts a dictionary.
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/// </summary>
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void EncryptDictionary(PdfDictionary dict)
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{
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PdfName[] names = dict.Elements.KeyNames;
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foreach (KeyValuePair<string, PdfItem> item in dict.Elements)
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{
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PdfString value1;
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PdfDictionary value2;
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PdfArray value3;
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if ((value1 = item.Value as PdfString) != null)
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EncryptString(value1);
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else if ((value2 = item.Value as PdfDictionary) != null)
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EncryptDictionary(value2);
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else if ((value3 = item.Value as PdfArray) != null)
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EncryptArray(value3);
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}
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if (dict.Stream != null)
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{
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byte[] bytes = dict.Stream.Value;
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if (bytes.Length != 0)
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{
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PrepareKey();
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EncryptRC4(bytes);
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dict.Stream.Value = bytes;
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}
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}
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}
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/// <summary>
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/// Encrypts an array.
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/// </summary>
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void EncryptArray(PdfArray array)
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{
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int count = array.Elements.Count;
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for (int idx = 0; idx < count; idx++)
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{
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PdfItem item = array.Elements[idx];
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PdfString value1;
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PdfDictionary value2;
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PdfArray value3;
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if ((value1 = item as PdfString) != null)
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EncryptString(value1);
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else if ((value2 = item as PdfDictionary) != null)
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EncryptDictionary(value2);
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else if ((value3 = item as PdfArray) != null)
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EncryptArray(value3);
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}
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}
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/// <summary>
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/// Encrypts a string.
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/// </summary>
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void EncryptString(PdfString value)
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{
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if (value.Length != 0)
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{
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byte[] bytes = value.EncryptionValue;
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PrepareKey();
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EncryptRC4(bytes);
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value.EncryptionValue = bytes;
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}
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}
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/// <summary>
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/// Encrypts an array.
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/// </summary>
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internal byte[] EncryptBytes(byte[] bytes)
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{
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if (bytes != null && bytes.Length != 0)
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{
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PrepareKey();
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EncryptRC4(bytes);
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}
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return bytes;
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}
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#region Encryption Algorithms
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/// <summary>
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/// Checks the password.
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/// </summary>
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/// <param name="inputPassword">Password or null if no password is provided.</param>
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public PasswordValidity ValidatePassword(string inputPassword)
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{
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// We can handle 40 and 128 bit standard encryption.
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string filter = Elements.GetName(PdfSecurityHandler.Keys.Filter);
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int v = Elements.GetInteger(PdfSecurityHandler.Keys.V);
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if (filter != "/Standard" || !(v >= 1 && v <= 3))
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throw new PdfReaderException(PSSR.UnknownEncryption);
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byte[] documentID = PdfEncoders.RawEncoding.GetBytes(Owner.Internals.FirstDocumentID);
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byte[] oValue = PdfEncoders.RawEncoding.GetBytes(Elements.GetString(Keys.O));
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byte[] uValue = PdfEncoders.RawEncoding.GetBytes(Elements.GetString(Keys.U));
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int pValue = Elements.GetInteger(Keys.P);
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int rValue = Elements.GetInteger(Keys.R);
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if (inputPassword == null)
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inputPassword = "";
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bool strongEncryption = rValue == 3;
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int keyLength = strongEncryption ? 16 : 32;
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// Try owner password first.
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//byte[] password = PdfEncoders.RawEncoding.GetBytes(inputPassword);
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InitWithOwnerPassword(documentID, inputPassword, oValue, pValue, strongEncryption);
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if (EqualsKey(uValue, keyLength))
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{
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_document.SecuritySettings._hasOwnerPermissions = true;
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return PasswordValidity.OwnerPassword;
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}
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_document.SecuritySettings._hasOwnerPermissions = false;
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// Now try user password.
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//password = PdfEncoders.RawEncoding.GetBytes(inputPassword);
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InitWithUserPassword(documentID, inputPassword, oValue, pValue, strongEncryption);
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if (EqualsKey(uValue, keyLength))
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return PasswordValidity.UserPassword;
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return PasswordValidity.Invalid;
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}
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[Conditional("DEBUG")]
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static void DumpBytes(string tag, byte[] bytes)
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{
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string dump = tag + ": ";
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for (int idx = 0; idx < bytes.Length; idx++)
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dump += String.Format("{0:X2}", bytes[idx]);
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Debug.WriteLine(dump);
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}
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/// <summary>
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/// Pads a password to a 32 byte array.
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/// </summary>
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static byte[] PadPassword(string password)
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{
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byte[] padded = new byte[32];
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if (password == null)
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Array.Copy(PasswordPadding, 0, padded, 0, 32);
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else
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{
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int length = password.Length;
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Array.Copy(PdfEncoders.RawEncoding.GetBytes(password), 0, padded, 0, Math.Min(length, 32));
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if (length < 32)
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Array.Copy(PasswordPadding, 0, padded, length, 32 - length);
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}
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return padded;
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}
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static readonly byte[] PasswordPadding = // 32 bytes password padding defined by Adobe
|
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{
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0x28, 0xBF, 0x4E, 0x5E, 0x4E, 0x75, 0x8A, 0x41, 0x64, 0x00, 0x4E, 0x56, 0xFF, 0xFA, 0x01, 0x08,
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0x2E, 0x2E, 0x00, 0xB6, 0xD0, 0x68, 0x3E, 0x80, 0x2F, 0x0C, 0xA9, 0xFE, 0x64, 0x53, 0x69, 0x7A,
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};
|
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|
|
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/// <summary>
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/// Generates the user key based on the padded user password.
|
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/// </summary>
|
|||
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void InitWithUserPassword(byte[] documentID, string userPassword, byte[] ownerKey, int permissions, bool strongEncryption)
|
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{
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InitEncryptionKey(documentID, PadPassword(userPassword), ownerKey, permissions, strongEncryption);
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SetupUserKey(documentID);
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}
|
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|
|
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/// <summary>
|
|||
|
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/// Generates the user key based on the padded owner password.
|
|||
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/// </summary>
|
|||
|
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void InitWithOwnerPassword(byte[] documentID, string ownerPassword, byte[] ownerKey, int permissions, bool strongEncryption)
|
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{
|
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byte[] userPad = ComputeOwnerKey(ownerKey, PadPassword(ownerPassword), strongEncryption);
|
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|
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InitEncryptionKey(documentID, userPad, ownerKey, permissions, strongEncryption);
|
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SetupUserKey(documentID);
|
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|
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}
|
|||
|
|
|
|||
|
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/// <summary>
|
|||
|
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/// Computes the padded user password from the padded owner password.
|
|||
|
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/// </summary>
|
|||
|
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byte[] ComputeOwnerKey(byte[] userPad, byte[] ownerPad, bool strongEncryption)
|
|||
|
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{
|
|||
|
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byte[] ownerKey = new byte[32];
|
|||
|
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//#if !SILVERLIGHT
|
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|
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byte[] digest = _md5.ComputeHash(ownerPad);
|
|||
|
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if (strongEncryption)
|
|||
|
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{
|
|||
|
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byte[] mkey = new byte[16];
|
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|
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// Hash the pad 50 times
|
|||
|
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for (int idx = 0; idx < 50; idx++)
|
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|
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digest = _md5.ComputeHash(digest);
|
|||
|
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Array.Copy(userPad, 0, ownerKey, 0, 32);
|
|||
|
|
// Encrypt the key
|
|||
|
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for (int i = 0; i < 20; i++)
|
|||
|
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{
|
|||
|
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for (int j = 0; j < mkey.Length; ++j)
|
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|
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mkey[j] = (byte)(digest[j] ^ i);
|
|||
|
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PrepareRC4Key(mkey);
|
|||
|
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EncryptRC4(ownerKey);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
PrepareRC4Key(digest, 0, 5);
|
|||
|
|
EncryptRC4(userPad, ownerKey);
|
|||
|
|
}
|
|||
|
|
//#endif
|
|||
|
|
return ownerKey;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Computes the encryption key.
|
|||
|
|
/// </summary>
|
|||
|
|
void InitEncryptionKey(byte[] documentID, byte[] userPad, byte[] ownerKey, int permissions, bool strongEncryption)
|
|||
|
|
{
|
|||
|
|
//#if !SILVERLIGHT
|
|||
|
|
_ownerKey = ownerKey;
|
|||
|
|
_encryptionKey = new byte[strongEncryption ? 16 : 5];
|
|||
|
|
|
|||
|
|
#if !NETFX_CORE
|
|||
|
|
_md5.Initialize();
|
|||
|
|
_md5.TransformBlock(userPad, 0, userPad.Length, userPad, 0);
|
|||
|
|
_md5.TransformBlock(ownerKey, 0, ownerKey.Length, ownerKey, 0);
|
|||
|
|
|
|||
|
|
// Split permission into 4 bytes
|
|||
|
|
byte[] permission = new byte[4];
|
|||
|
|
permission[0] = (byte)permissions;
|
|||
|
|
permission[1] = (byte)(permissions >> 8);
|
|||
|
|
permission[2] = (byte)(permissions >> 16);
|
|||
|
|
permission[3] = (byte)(permissions >> 24);
|
|||
|
|
_md5.TransformBlock(permission, 0, 4, permission, 0);
|
|||
|
|
_md5.TransformBlock(documentID, 0, documentID.Length, documentID, 0);
|
|||
|
|
_md5.TransformFinalBlock(permission, 0, 0);
|
|||
|
|
byte[] digest = _md5.Hash;
|
|||
|
|
_md5.Initialize();
|
|||
|
|
// Create the hash 50 times (only for 128 bit)
|
|||
|
|
if (_encryptionKey.Length == 16)
|
|||
|
|
{
|
|||
|
|
for (int idx = 0; idx < 50; idx++)
|
|||
|
|
{
|
|||
|
|
digest = _md5.ComputeHash(digest);
|
|||
|
|
_md5.Initialize();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
Array.Copy(digest, 0, _encryptionKey, 0, _encryptionKey.Length);
|
|||
|
|
//#endif
|
|||
|
|
#endif
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Computes the user key.
|
|||
|
|
/// </summary>
|
|||
|
|
void SetupUserKey(byte[] documentID)
|
|||
|
|
{
|
|||
|
|
#if !NETFX_CORE
|
|||
|
|
//#if !SILVERLIGHT
|
|||
|
|
if (_encryptionKey.Length == 16)
|
|||
|
|
{
|
|||
|
|
_md5.TransformBlock(PasswordPadding, 0, PasswordPadding.Length, PasswordPadding, 0);
|
|||
|
|
_md5.TransformFinalBlock(documentID, 0, documentID.Length);
|
|||
|
|
byte[] digest = _md5.Hash;
|
|||
|
|
_md5.Initialize();
|
|||
|
|
Array.Copy(digest, 0, _userKey, 0, 16);
|
|||
|
|
for (int idx = 16; idx < 32; idx++)
|
|||
|
|
_userKey[idx] = 0;
|
|||
|
|
//Encrypt the key
|
|||
|
|
for (int i = 0; i < 20; i++)
|
|||
|
|
{
|
|||
|
|
for (int j = 0; j < _encryptionKey.Length; j++)
|
|||
|
|
digest[j] = (byte)(_encryptionKey[j] ^ i);
|
|||
|
|
PrepareRC4Key(digest, 0, _encryptionKey.Length);
|
|||
|
|
EncryptRC4(_userKey, 0, 16);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
PrepareRC4Key(_encryptionKey);
|
|||
|
|
EncryptRC4(PasswordPadding, _userKey);
|
|||
|
|
}
|
|||
|
|
//#endif
|
|||
|
|
#endif
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Prepare the encryption key.
|
|||
|
|
/// </summary>
|
|||
|
|
void PrepareKey()
|
|||
|
|
{
|
|||
|
|
if (_key != null && _keySize > 0) //!!!mod 2017-11-06 Added "if" because PrepareRC4Key fails if _key is null. But _key appears to be always null, so maybe PrepareKey() is obsolete.
|
|||
|
|
PrepareRC4Key(_key, 0, _keySize);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Prepare the encryption key.
|
|||
|
|
/// </summary>
|
|||
|
|
void PrepareRC4Key(byte[] key)
|
|||
|
|
{
|
|||
|
|
PrepareRC4Key(key, 0, key.Length);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Prepare the encryption key.
|
|||
|
|
/// </summary>
|
|||
|
|
void PrepareRC4Key(byte[] key, int offset, int length)
|
|||
|
|
{
|
|||
|
|
int idx1 = 0;
|
|||
|
|
int idx2 = 0;
|
|||
|
|
for (int idx = 0; idx < 256; idx++)
|
|||
|
|
_state[idx] = (byte)idx;
|
|||
|
|
byte tmp;
|
|||
|
|
for (int idx = 0; idx < 256; idx++)
|
|||
|
|
{
|
|||
|
|
idx2 = (key[idx1 + offset] + _state[idx] + idx2) & 255;
|
|||
|
|
tmp = _state[idx];
|
|||
|
|
_state[idx] = _state[idx2];
|
|||
|
|
_state[idx2] = tmp;
|
|||
|
|
idx1 = (idx1 + 1) % length;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Encrypts the data.
|
|||
|
|
/// </summary>
|
|||
|
|
// ReSharper disable InconsistentNaming
|
|||
|
|
void EncryptRC4(byte[] data)
|
|||
|
|
// ReSharper restore InconsistentNaming
|
|||
|
|
{
|
|||
|
|
EncryptRC4(data, 0, data.Length, data);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Encrypts the data.
|
|||
|
|
/// </summary>
|
|||
|
|
// ReSharper disable InconsistentNaming
|
|||
|
|
void EncryptRC4(byte[] data, int offset, int length)
|
|||
|
|
// ReSharper restore InconsistentNaming
|
|||
|
|
{
|
|||
|
|
EncryptRC4(data, offset, length, data);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Encrypts the data.
|
|||
|
|
/// </summary>
|
|||
|
|
void EncryptRC4(byte[] inputData, byte[] outputData)
|
|||
|
|
{
|
|||
|
|
EncryptRC4(inputData, 0, inputData.Length, outputData);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Encrypts the data.
|
|||
|
|
/// </summary>
|
|||
|
|
void EncryptRC4(byte[] inputData, int offset, int length, byte[] outputData)
|
|||
|
|
{
|
|||
|
|
length += offset;
|
|||
|
|
int x = 0, y = 0;
|
|||
|
|
byte b;
|
|||
|
|
for (int idx = offset; idx < length; idx++)
|
|||
|
|
{
|
|||
|
|
x = (x + 1) & 255;
|
|||
|
|
y = (_state[x] + y) & 255;
|
|||
|
|
b = _state[x];
|
|||
|
|
_state[x] = _state[y];
|
|||
|
|
_state[y] = b;
|
|||
|
|
outputData[idx] = (byte)(inputData[idx] ^ _state[(_state[x] + _state[y]) & 255]);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Checks whether the calculated key correct.
|
|||
|
|
/// </summary>
|
|||
|
|
bool EqualsKey(byte[] value, int length)
|
|||
|
|
{
|
|||
|
|
for (int idx = 0; idx < length; idx++)
|
|||
|
|
{
|
|||
|
|
if (_userKey[idx] != value[idx])
|
|||
|
|
return false;
|
|||
|
|
}
|
|||
|
|
return true;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Set the hash key for the specified object.
|
|||
|
|
/// </summary>
|
|||
|
|
internal void SetHashKey(PdfObjectID id)
|
|||
|
|
{
|
|||
|
|
#if !NETFX_CORE
|
|||
|
|
//#if !SILVERLIGHT
|
|||
|
|
byte[] objectId = new byte[5];
|
|||
|
|
_md5.Initialize();
|
|||
|
|
// Split the object number and generation
|
|||
|
|
objectId[0] = (byte)id.ObjectNumber;
|
|||
|
|
objectId[1] = (byte)(id.ObjectNumber >> 8);
|
|||
|
|
objectId[2] = (byte)(id.ObjectNumber >> 16);
|
|||
|
|
objectId[3] = (byte)id.GenerationNumber;
|
|||
|
|
objectId[4] = (byte)(id.GenerationNumber >> 8);
|
|||
|
|
_md5.TransformBlock(_encryptionKey, 0, _encryptionKey.Length, _encryptionKey, 0);
|
|||
|
|
_md5.TransformFinalBlock(objectId, 0, objectId.Length);
|
|||
|
|
_key = _md5.Hash;
|
|||
|
|
_md5.Initialize();
|
|||
|
|
_keySize = _encryptionKey.Length + 5;
|
|||
|
|
if (_keySize > 16)
|
|||
|
|
_keySize = 16;
|
|||
|
|
//#endif
|
|||
|
|
#endif
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Prepares the security handler for encrypting the document.
|
|||
|
|
/// </summary>
|
|||
|
|
public void PrepareEncryption()
|
|||
|
|
{
|
|||
|
|
//#if !SILVERLIGHT
|
|||
|
|
Debug.Assert(_document._securitySettings.DocumentSecurityLevel != PdfDocumentSecurityLevel.None);
|
|||
|
|
int permissions = (int)Permission;
|
|||
|
|
bool strongEncryption = _document._securitySettings.DocumentSecurityLevel == PdfDocumentSecurityLevel.Encrypted128Bit;
|
|||
|
|
|
|||
|
|
PdfInteger vValue;
|
|||
|
|
PdfInteger length;
|
|||
|
|
PdfInteger rValue;
|
|||
|
|
|
|||
|
|
if (strongEncryption)
|
|||
|
|
{
|
|||
|
|
vValue = new PdfInteger(2);
|
|||
|
|
length = new PdfInteger(128);
|
|||
|
|
rValue = new PdfInteger(3);
|
|||
|
|
}
|
|||
|
|
else
|
|||
|
|
{
|
|||
|
|
vValue = new PdfInteger(1);
|
|||
|
|
length = new PdfInteger(40);
|
|||
|
|
rValue = new PdfInteger(2);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
if (String.IsNullOrEmpty(_userPassword))
|
|||
|
|
_userPassword = "";
|
|||
|
|
// Use user password twice if no owner password provided.
|
|||
|
|
if (String.IsNullOrEmpty(_ownerPassword))
|
|||
|
|
_ownerPassword = _userPassword;
|
|||
|
|
|
|||
|
|
// Correct permission bits
|
|||
|
|
permissions |= (int)(strongEncryption ? (uint)0xfffff0c0 : (uint)0xffffffc0);
|
|||
|
|
permissions &= unchecked((int)0xfffffffc);
|
|||
|
|
|
|||
|
|
PdfInteger pValue = new PdfInteger(permissions);
|
|||
|
|
|
|||
|
|
Debug.Assert(_ownerPassword.Length > 0, "Empty owner password.");
|
|||
|
|
byte[] userPad = PadPassword(_userPassword);
|
|||
|
|
byte[] ownerPad = PadPassword(_ownerPassword);
|
|||
|
|
|
|||
|
|
_md5.Initialize();
|
|||
|
|
_ownerKey = ComputeOwnerKey(userPad, ownerPad, strongEncryption);
|
|||
|
|
byte[] documentID = PdfEncoders.RawEncoding.GetBytes(_document.Internals.FirstDocumentID);
|
|||
|
|
InitWithUserPassword(documentID, _userPassword, _ownerKey, permissions, strongEncryption);
|
|||
|
|
|
|||
|
|
PdfString oValue = new PdfString(PdfEncoders.RawEncoding.GetString(_ownerKey, 0, _ownerKey.Length));
|
|||
|
|
PdfString uValue = new PdfString(PdfEncoders.RawEncoding.GetString(_userKey, 0, _userKey.Length));
|
|||
|
|
|
|||
|
|
Elements[Keys.Filter] = new PdfName("/Standard");
|
|||
|
|
Elements[Keys.V] = vValue;
|
|||
|
|
Elements[Keys.Length] = length;
|
|||
|
|
Elements[Keys.R] = rValue;
|
|||
|
|
Elements[Keys.O] = oValue;
|
|||
|
|
Elements[Keys.U] = uValue;
|
|||
|
|
Elements[Keys.P] = pValue;
|
|||
|
|
//#endif
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// The global encryption key.
|
|||
|
|
/// </summary>
|
|||
|
|
byte[] _encryptionKey;
|
|||
|
|
|
|||
|
|
#if !SILVERLIGHT && !UWP
|
|||
|
|
/// <summary>
|
|||
|
|
/// The message digest algorithm MD5.
|
|||
|
|
/// </summary>
|
|||
|
|
readonly MD5 _md5 = new MD5CryptoServiceProvider();
|
|||
|
|
#if DEBUG_
|
|||
|
|
readonly MD5Managed _md5M = new MD5Managed();
|
|||
|
|
#endif
|
|||
|
|
#else
|
|||
|
|
readonly MD5Managed _md5 = new MD5Managed();
|
|||
|
|
#endif
|
|||
|
|
#if NETFX_CORE
|
|||
|
|
// readonly MD5Managed _md5 = new MD5Managed();
|
|||
|
|
#endif
|
|||
|
|
/// <summary>
|
|||
|
|
/// Bytes used for RC4 encryption.
|
|||
|
|
/// </summary>
|
|||
|
|
readonly byte[] _state = new byte[256];
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// The encryption key for the owner.
|
|||
|
|
/// </summary>
|
|||
|
|
byte[] _ownerKey = new byte[32];
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// The encryption key for the user.
|
|||
|
|
/// </summary>
|
|||
|
|
readonly byte[] _userKey = new byte[32];
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// The encryption key for a particular object/generation.
|
|||
|
|
/// </summary>
|
|||
|
|
byte[] _key;
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// The encryption key length for a particular object/generation.
|
|||
|
|
/// </summary>
|
|||
|
|
int _keySize;
|
|||
|
|
|
|||
|
|
#endregion
|
|||
|
|
|
|||
|
|
internal override void WriteObject(PdfWriter writer)
|
|||
|
|
{
|
|||
|
|
// Don't encrypt myself.
|
|||
|
|
PdfStandardSecurityHandler securityHandler = writer.SecurityHandler;
|
|||
|
|
writer.SecurityHandler = null;
|
|||
|
|
base.WriteObject(writer);
|
|||
|
|
writer.SecurityHandler = securityHandler;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
#region Keys
|
|||
|
|
/// <summary>
|
|||
|
|
/// Predefined keys of this dictionary.
|
|||
|
|
/// </summary>
|
|||
|
|
internal sealed new class Keys : PdfSecurityHandler.Keys
|
|||
|
|
{
|
|||
|
|
/// <summary>
|
|||
|
|
/// (Required) A number specifying which revision of the standard security handler
|
|||
|
|
/// should be used to interpret this dictionary:
|
|||
|
|
/// <20> 2 if the document is encrypted with a V value less than 2 and does not have any of
|
|||
|
|
/// the access permissions set (by means of the P entry, below) that are designated
|
|||
|
|
/// "Revision 3 or greater".
|
|||
|
|
/// <20> 3 if the document is encrypted with a V value of 2 or 3, or has any "Revision 3 or
|
|||
|
|
/// greater" access permissions set.
|
|||
|
|
/// <20> 4 if the document is encrypted with a V value of 4
|
|||
|
|
/// </summary>
|
|||
|
|
[KeyInfo(KeyType.Integer | KeyType.Required)]
|
|||
|
|
public const string R = "/R";
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// (Required) A 32-byte string, based on both the owner and user passwords, that is
|
|||
|
|
/// used in computing the encryption key and in determining whether a valid owner
|
|||
|
|
/// password was entered.
|
|||
|
|
/// </summary>
|
|||
|
|
[KeyInfo(KeyType.String | KeyType.Required)]
|
|||
|
|
public const string O = "/O";
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// (Required) A 32-byte string, based on the user password, that is used in determining
|
|||
|
|
/// whether to prompt the user for a password and, if so, whether a valid user or owner
|
|||
|
|
/// password was entered.
|
|||
|
|
/// </summary>
|
|||
|
|
[KeyInfo(KeyType.String | KeyType.Required)]
|
|||
|
|
public const string U = "/U";
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// (Required) A set of flags specifying which operations are permitted when the document
|
|||
|
|
/// is opened with user access.
|
|||
|
|
/// </summary>
|
|||
|
|
[KeyInfo(KeyType.Integer | KeyType.Required)]
|
|||
|
|
public const string P = "/P";
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// (Optional; meaningful only when the value of V is 4; PDF 1.5) Indicates whether
|
|||
|
|
/// the document-level metadata stream is to be encrypted. Applications should respect this value.
|
|||
|
|
/// Default value: true.
|
|||
|
|
/// </summary>
|
|||
|
|
[KeyInfo(KeyType.Boolean | KeyType.Optional)]
|
|||
|
|
public const string EncryptMetadata = "/EncryptMetadata";
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Gets the KeysMeta for these keys.
|
|||
|
|
/// </summary>
|
|||
|
|
public static DictionaryMeta Meta
|
|||
|
|
{
|
|||
|
|
get { return _meta ?? (_meta = CreateMeta(typeof(Keys))); }
|
|||
|
|
}
|
|||
|
|
static DictionaryMeta _meta;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/// <summary>
|
|||
|
|
/// Gets the KeysMeta of this dictionary type.
|
|||
|
|
/// </summary>
|
|||
|
|
internal override DictionaryMeta Meta
|
|||
|
|
{
|
|||
|
|
get { return Keys.Meta; }
|
|||
|
|
}
|
|||
|
|
#endregion
|
|||
|
|
}
|
|||
|
|
}
|