コード例 #1
0
        /// <summary>
        ///     Computes the O(owner) value in the encryption dictionary.
        /// </summary>
        /// <remarks>
        ///     Corresponds to algorithm 3.3 on page 69 of the PDF specficiation.
        /// </remarks>
        /// <param name="options">
        ///     The user supplied PDF options that provides access to the passwords.
        /// </param>
        private void CreateOwnerEntry(SecurityOptions options)
        {
            // Pad or truncate the owner password string.
            // If there is no owner password use the user password instead.
            string password = options.OwnerPassword;

            if (password == null)
            {
                password = options.UserPassword;
            }
            byte[] paddedPassword = PadPassword(password);

            // Create an MD5 hash from the padded password.
            // The first 5 bytes of this hash will be used as an ARC4 key.
            MD5 md5 = MD5.Create();

            byte[] hash = md5.ComputeHash(paddedPassword);

            // Pad or truncate the user password string.
            byte[] paddedUserPassword = PadPassword(options.UserPassword);

            // Encrypt the padded user password using the key generated above.
            Arc4 arc4 = new Arc4(hash, 0, 5);

            ownerEntry = new byte[32];
            arc4.Encrypt(paddedUserPassword, ownerEntry);
        }
コード例 #2
0
        /// <summary>
        ///     Encrypts the passed byte array using the ARC4 cipher.
        /// </summary>
        public byte[] Encrypt(byte[] data, PdfObjectId objectId)
        {
            Arc4 arc4 = new Arc4(ComputeEncryptionKey31(masterKey, objectId));

            arc4.Encrypt(data, data);
            return(data);
        }
コード例 #3
0
        /// <summary>
        ///     Computes the U(user) value in the encryption dictionary.
        /// </summary>
        /// <remarks>
        ///     Corresponds to algorithm 3.4 on page 70 of the PDF specficiation.
        /// </remarks>
        /// <param name="options">
        ///     The user supplied PDF options that provides access to the passwords.
        /// </param>
        private void CreateUserEntry(SecurityOptions options)
        {
            // Encrypt the 32-byte padding string using the master key.
            Arc4 arc4 = new Arc4(masterKey);

            userEntry = new byte[32];
            arc4.Encrypt(Padding, userEntry);
        }
コード例 #4
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        /// <summary>
        ///     Performs the actual checking of the user password.
        /// </summary>
        private static bool CheckUserPassword(
            byte[] paddedPassword, byte[] userEntry, byte[] ownerEntry, int permissions, byte[] fileId)
        {
            // Compute an encryption key from the supplied information.
            byte[] key = ComputeEncryptionKey32(
                paddedPassword, ownerEntry, permissions, fileId);

            // Decrpt the User entry using the key.
            Arc4 arc4 = new Arc4(key);

            byte[] decryptedUserEntry = new byte[32];
            arc4.Encrypt(userEntry, decryptedUserEntry);

            // Compare the two arrays, if they match then the
            // supplied password is correct.
            return(CompareArray(Padding, decryptedUserEntry));
        }
コード例 #5
0
        /// <summary>
        ///     Checks the owner password.
        /// </summary>
        internal static bool CheckOwnerPassword(
            string password, byte[] userEntry, byte[] ownerEntry, int permissions, byte[] fileId)
        {
            // Compute an encryption key from the supplied information.
            MD5 md5 = MD5.Create();

            byte[] hash = md5.ComputeHash(PadPassword(password));

            // Decrpt the Owner entry using the key.
            Arc4 arc4 = new Arc4(hash, 0, 5);

            byte[] decryptedOwnerEntry = new byte[32];
            arc4.Encrypt(ownerEntry, decryptedOwnerEntry);

            // The decryped owner entry is the correct user password,
            // then the owner password is also correct.
            return(CheckUserPassword(decryptedOwnerEntry, userEntry, ownerEntry, permissions, fileId));
        }
コード例 #6
0
ファイル: SecurityManager.cs プロジェクト: nholik/Fo.Net
        /// <summary>
        ///     Computes the O(owner) value in the encryption dictionary.
        /// </summary>
        /// <remarks>
        ///     Corresponds to algorithm 3.3 on page 69 of the PDF specficiation.
        /// </remarks>
        /// <param name="options">
        ///     The user supplied PDF options that provides access to the passwords.
        /// </param>
        private void CreateOwnerEntry(SecurityOptions options)
        {
            // Pad or truncate the owner password string.
            // If there is no owner password use the user password instead.
            string password = options.OwnerPassword;
            if (password == null)
            {
                password = options.UserPassword;
            }
            byte[] paddedPassword = PadPassword(password);

            // Create an MD5 hash from the padded password.
            // The first 5 bytes of this hash will be used as an ARC4 key.
            MD5 md5 = MD5.Create();
            byte[] hash = md5.ComputeHash(paddedPassword);

            // Pad or truncate the user password string.
            byte[] paddedUserPassword = PadPassword(options.UserPassword);

            // Encrypt the padded user password using the key generated above.
            Arc4 arc4 = new Arc4(hash, 0, 5);
            ownerEntry = new byte[32];
            arc4.Encrypt(paddedUserPassword, ownerEntry);
        }
コード例 #7
0
ファイル: SecurityManager.cs プロジェクト: nholik/Fo.Net
        /// <summary>
        ///     Checks the owner password.
        /// </summary>
        internal static bool CheckOwnerPassword(
            string password, byte[] userEntry, byte[] ownerEntry, int permissions, byte[] fileId)
        {
            // Compute an encryption key from the supplied information.
            MD5 md5 = MD5.Create();
            byte[] hash = md5.ComputeHash(PadPassword(password));

            // Decrpt the Owner entry using the key.
            Arc4 arc4 = new Arc4(hash, 0, 5);
            byte[] decryptedOwnerEntry = new byte[32];
            arc4.Encrypt(ownerEntry, decryptedOwnerEntry);

            // The decryped owner entry is the correct user password,
            // then the owner password is also correct.
            return CheckUserPassword(decryptedOwnerEntry, userEntry, ownerEntry, permissions, fileId);
        }
コード例 #8
0
ファイル: SecurityManager.cs プロジェクト: nholik/Fo.Net
        /// <summary>
        ///     Performs the actual checking of the user password.
        /// </summary>
        private static bool CheckUserPassword(
            byte[] paddedPassword, byte[] userEntry, byte[] ownerEntry, int permissions, byte[] fileId)
        {
            // Compute an encryption key from the supplied information.
            byte[] key = ComputeEncryptionKey32(
                paddedPassword, ownerEntry, permissions, fileId);

            // Decrpt the User entry using the key.
            Arc4 arc4 = new Arc4(key);
            byte[] decryptedUserEntry = new byte[32];
            arc4.Encrypt(userEntry, decryptedUserEntry);

            // Compare the two arrays, if they match then the 
            // supplied password is correct.
            return CompareArray(Padding, decryptedUserEntry);
        }
コード例 #9
0
ファイル: SecurityManager.cs プロジェクト: nholik/Fo.Net
 /// <summary>
 ///     Encrypts the passed byte array using the ARC4 cipher.
 /// </summary>
 public byte[] Encrypt(byte[] data, PdfObjectId objectId)
 {
     Arc4 arc4 = new Arc4(ComputeEncryptionKey31(masterKey, objectId));
     arc4.Encrypt(data, data);
     return data;
 }
コード例 #10
0
ファイル: SecurityManager.cs プロジェクト: nholik/Fo.Net
 /// <summary>
 ///     Computes the U(user) value in the encryption dictionary.
 /// </summary>
 /// <remarks>
 ///     Corresponds to algorithm 3.4 on page 70 of the PDF specficiation.
 /// </remarks>
 /// <param name="options">
 ///     The user supplied PDF options that provides access to the passwords.
 /// </param>
 private void CreateUserEntry(SecurityOptions options)
 {
     // Encrypt the 32-byte padding string using the master key.
     Arc4 arc4 = new Arc4(masterKey);
     userEntry = new byte[32];
     arc4.Encrypt(Padding, userEntry);
 }