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/*
This file is part of the iText (R) project.
Copyright (c) 1998-2023 Apryse Group NV
Authors: Apryse Software.
This program is offered under a commercial and under the AGPL license.
For commercial licensing, contact us at https://itextpdf.com/sales. For AGPL licensing, see below.
AGPL licensing:
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see .
*/
package com.itextpdf.kernel.crypto.securityhandler;
import com.itextpdf.kernel.pdf.PdfBoolean;
import com.itextpdf.kernel.pdf.PdfDictionary;
import com.itextpdf.kernel.pdf.PdfName;
import com.itextpdf.kernel.pdf.PdfNumber;
public class StandardHandlerUsingStandard128 extends StandardHandlerUsingStandard40 {
public StandardHandlerUsingStandard128(PdfDictionary encryptionDictionary, byte[] userPassword, byte[] ownerPassword,
int permissions, boolean encryptMetadata, boolean embeddedFilesOnly, byte[] documentId) {
super(encryptionDictionary, userPassword, ownerPassword, permissions, encryptMetadata, embeddedFilesOnly, documentId);
}
public StandardHandlerUsingStandard128(PdfDictionary encryptionDictionary, byte[] password, byte[] documentId, boolean encryptMetadata) {
super(encryptionDictionary, password, documentId, encryptMetadata);
}
@Override
protected void calculatePermissions(int permissions) {
permissions |= PERMS_MASK_1_FOR_REVISION_3_OR_GREATER;
permissions &= PERMS_MASK_2;
this.permissions = permissions;
}
@Override
protected byte[] computeOwnerKey(byte[] userPad, byte[] ownerPad) {
byte[] ownerKey = new byte[32];
byte[] digest = md5.digest(ownerPad);
byte[] mkey = new byte[keyLength / 8];
// only use for the input as many bit as the key consists of
for (int k = 0; k < 50; ++k) {
md5.update(digest, 0, mkey.length);
System.arraycopy(md5.digest(), 0, digest, 0, mkey.length);
}
System.arraycopy(userPad, 0, ownerKey, 0, 32);
for (int i = 0; i < 20; ++i) {
for (int j = 0; j < mkey.length; ++j)
mkey[j] = (byte) (digest[j] ^ i);
arcfour.prepareARCFOURKey(mkey);
arcfour.encryptARCFOUR(ownerKey);
}
return ownerKey;
}
@Override
protected void computeGlobalEncryptionKey(byte[] userPad, byte[] ownerKey, boolean encryptMetadata) {
mkey = new byte[keyLength / 8];
// fixed by ujihara in order to follow PDF reference
md5.reset();
md5.update(userPad);
md5.update(ownerKey);
byte[] ext = new byte[4];
ext[0] = (byte) permissions;
ext[1] = (byte) (permissions >> 8);
ext[2] = (byte) (permissions >> 16);
ext[3] = (byte) (permissions >> 24);
md5.update(ext, 0, 4);
if (documentId != null)
md5.update(documentId);
if (!encryptMetadata)
md5.update(metadataPad);
byte[] digest = new byte[mkey.length];
System.arraycopy(md5.digest(), 0, digest, 0, mkey.length);
// only use the really needed bits as input for the hash
for (int k = 0; k < 50; ++k) {
System.arraycopy(md5.digest(digest), 0, digest, 0, mkey.length);
}
System.arraycopy(digest, 0, mkey, 0, mkey.length);
}
@Override
protected byte[] computeUserKey() {
byte[] userKey = new byte[32];
md5.update(pad);
byte[] digest = md5.digest(documentId);
System.arraycopy(digest, 0, userKey, 0, 16);
for (int k = 16; k < 32; ++k)
userKey[k] = 0;
for (int i = 0; i < 20; ++i) {
for (int j = 0; j < mkey.length; ++j)
digest[j] = (byte) (mkey[j] ^ i);
arcfour.prepareARCFOURKey(digest, 0, mkey.length);
arcfour.encryptARCFOUR(userKey, 0, 16);
}
return userKey;
}
@Override
protected void setSpecificHandlerDicEntries(PdfDictionary encryptionDictionary, boolean encryptMetadata, boolean embeddedFilesOnly) {
if (encryptMetadata) {
encryptionDictionary.put(PdfName.R, new PdfNumber(3));
encryptionDictionary.put(PdfName.V, new PdfNumber(2));
} else {
encryptionDictionary.put(PdfName.EncryptMetadata, PdfBoolean.FALSE);
encryptionDictionary.put(PdfName.R, new PdfNumber(4));
encryptionDictionary.put(PdfName.V, new PdfNumber(4));
PdfDictionary stdcf = new PdfDictionary();
stdcf.put(PdfName.Length, new PdfNumber(16));
if (embeddedFilesOnly) {
stdcf.put(PdfName.AuthEvent, PdfName.EFOpen);
encryptionDictionary.put(PdfName.EFF, PdfName.StdCF);
encryptionDictionary.put(PdfName.StrF, PdfName.Identity);
encryptionDictionary.put(PdfName.StmF, PdfName.Identity);
} else {
stdcf.put(PdfName.AuthEvent, PdfName.DocOpen);
encryptionDictionary.put(PdfName.StrF, PdfName.StdCF);
encryptionDictionary.put(PdfName.StmF, PdfName.StdCF);
}
stdcf.put(PdfName.CFM, PdfName.V2);
PdfDictionary cf = new PdfDictionary();
cf.put(PdfName.StdCF, stdcf);
encryptionDictionary.put(PdfName.CF, cf);
}
}
@Override
protected boolean isValidPassword(byte[] uValue, byte[] userKey) {
return !equalsArray(uValue, userKey, 16);
}
}
