/// <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);
}
/// <summary>
/// Computes the master key that is used to encrypt string and stream data
/// in the PDF document.
/// </summary>
/// <param name="options">
/// The user supplied PDF options that provides access to the passwords and
/// the access permissions.
/// </param>
/// <param name="fileId">
/// The PDF document's file identifier (see section 8.3 of PDF specification).
/// </param>
private void CreateMasterKey(SecurityOptions options, FileIdentifier fileId)
{
masterKey = ComputeEncryptionKey32(
PadPassword(options.UserPassword),
ownerEntry,
options.Permissions,
fileId.CreatedPart);
}
/// <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);
}
/// <summary>
/// Constructs a new standard security manager.
/// </summary>
/// <param name="options">
/// The user supplied PDF options that provides access to the passwords and
/// the access permissions.
/// </param>
/// <param name="fileId">
/// The PDF document's file identifier (see section 8.3 of PDF specification).
/// </param>
public SecurityManager(SecurityOptions options, FileIdentifier fileId)
{
// note: The order that these keys are created is important.
CreateOwnerEntry(options);
CreateMasterKey(options, fileId); // requires the owner entry
CreateUserEntry(options); // requires the master key
this.permissions = options.Permissions;
}
/// <summary>
/// Computes the master key that is used to encrypt string and stream data
/// in the PDF document.
/// </summary>
/// <param name="options">
/// The user supplied PDF options that provides access to the passwords and
/// the access permissions.
/// </param>
/// <param name="fileId">
/// The PDF document's file identifier (see section 8.3 of PDF specification).
/// </param>
private void CreateMasterKey(SecurityOptions options, FileIdentifier fileId)
{
masterKey = ComputeEncryptionKey32(
PadPassword(options.UserPassword),
ownerEntry,
options.Permissions,
fileId.CreatedPart);
}
/// <summary>
/// Constructs a new standard security manager.
/// </summary>
/// <param name="options">
/// The user supplied PDF options that provides access to the passwords and
/// the access permissions.
/// </param>
/// <param name="fileId">
/// The PDF document's file identifier (see section 8.3 of PDF specification).
/// </param>
public SecurityManager(SecurityOptions options, FileIdentifier fileId)
{
// note: The order that these keys are created is important.
CreateOwnerEntry(options);
CreateMasterKey(options, fileId); // requires the owner entry
CreateUserEntry(options); // requires the master key
this.permissions = options.Permissions;
}
/// <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);
}
/// <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);
}
public void SetOptions(PdfRendererOptions options)
{
// Configure the /Info dictionary.
info = new PdfInfo(doc.NextObjectId());
if (options.Title != null)
{
info.Title = new PdfString(options.Title);
}
if (options.Author != null)
{
info.Author = new PdfString(options.Author);
}
if (options.Subject != null)
{
info.Subject = new PdfString(options.Subject);
}
if (options.Keywords != String.Empty)
{
info.Keywords = new PdfString(options.Keywords);
}
if (options.Creator != null)
{
info.Creator = new PdfString(options.Creator);
}
if (options.Producer != null)
{
info.Producer = new PdfString(options.Producer);
}
info.CreationDate = new PdfString(PdfDate.Format(DateTime.Now));
this.objects.Add(info);
// Configure the security options.
if (options.UserPassword != null ||
options.OwnerPassword != null ||
options.HasPermissions)
{
SecurityOptions securityOptions = new SecurityOptions();
securityOptions.UserPassword = options.UserPassword;
securityOptions.OwnerPassword = options.OwnerPassword;
securityOptions.EnableAdding(options.EnableAdd);
securityOptions.EnableChanging(options.EnableModify);
securityOptions.EnableCopying(options.EnableCopy);
securityOptions.EnablePrinting(options.EnablePrinting);
doc.SecurityOptions = securityOptions;
encrypt = doc.Writer.SecurityManager.GetEncrypt(doc.NextObjectId());
this.objects.Add(encrypt);
}
}