Class PDFEncryption

public final byte[] computeEncryptedKey(byte[] password,
                                        byte[] o,
                                        int permissions,
                                        byte[] id,
                                        int revision,
                                        int length)
            throws CryptographyException

This will compute the encrypted key.

Parameters:

password - The password used to compute the encrypted key.

o - The owner password hash.

permissions - The permissions for the document.

id - The document id.

revision - The security revision.

length - The length of the encryption key.

Returns:

The encryption key.

Throws:

CryptographyException - If there is an error computing the key.

public final byte[] computeOwnerPassword(byte[] ownerPassword,
                                         byte[] userPassword,
                                         int revision,
                                         int length)
            throws CryptographyException,
                   IOException

This algorithm is taked from PDF Reference 1.4 Algorithm 3.3 Page 79.

Parameters:

ownerPassword - The plain owner password.

userPassword - The plain user password.

revision - The version of the security.

length - The length of the document.

Returns:

The computed owner password.

Throws:

CryptographyException - If there is an error computing O.

public final byte[] computeUserPassword(byte[] password,
                                        byte[] o,
                                        int permissions,
                                        byte[] id,
                                        int revision,
                                        int length)
            throws CryptographyException,
                   IOException

This will compute the user password hash.

Parameters:

password - The plain text password.

o - The owner password hash.

permissions - The document permissions.

id - The document id.

revision - The revision of the encryption.

length - The length of the encryption key.

Returns:

The user password.

Throws:

CryptographyException - If there is an error computing the user password.

public final void encryptData(long objectNumber,
                              long genNumber,
                              byte[] key,
                              InputStream data,
                              OutputStream output)
            throws CryptographyException,
                   IOException

This will encrypt a piece of data.

Parameters:

objectNumber - The id for the object.

genNumber - The generation id for the object.

key - The key used to encrypt the data.

data - The data to encrypt/decrypt.

output - The stream to write to.

Throws:

CryptographyException - If there is an error encrypting the data.

public final byte[] getUserPassword(byte[] ownerPassword,
                                    byte[] o,
                                    int revision,
                                    long length)
            throws CryptographyException,
                   IOException

This will get the user password from the owner password and the documents o value.

Parameters:

ownerPassword - The plaintext owner password.

o - The document's o entry.

revision - The document revision number.

length - The length of the encryption.

Returns:

The plaintext padded user password.

Throws:

CryptographyException - If there is an error getting the user password.

public final boolean isOwnerPassword(byte[] ownerPassword,
                                     byte[] u,
                                     byte[] o,
                                     int permissions,
                                     byte[] id,
                                     int revision,
                                     int length)
            throws CryptographyException,
                   IOException

This will tell if this is the owner password or not.

Parameters:

ownerPassword - The plaintext owner password.

u - The U value from the PDF Document.

o - The owner password hash.

permissions - The document permissions.

id - The document id.

revision - The revision of the encryption.

length - The length of the encryption key.

Returns:

true if the owner password matches the one from the document.

Throws:

CryptographyException - If there is an error while executing crypt functions.

public final boolean isUserPassword(byte[] password,
                                    byte[] u,
                                    byte[] o,
                                    int permissions,
                                    byte[] id,
                                    int revision,
                                    int length)
            throws CryptographyException,
                   IOException

This will tell if this is a valid user password. Algorithm 3.6 pg 80

Parameters:

password - The password to test.

u - The U value from the PDF Document.

o - The owner password hash.

permissions - The document permissions.

id - The document id.

revision - The revision of the encryption.

length - The length of the encryption key.

Returns:

true If this is the correct user password.

Throws:

CryptographyException - If there is an error computing the value.