Package com.healthmarketscience.jackcess.crypt

Class EncryptionUtil

java.lang.Object

com.healthmarketscience.jackcess.crypt.EncryptionUtil

public class EncryptionUtil
extends Object

Adds and removes the encryption on a database. Reading an encrypted database needs CryptCodecProvider instead, and the jet database password, which is a different feature, is PasswordUtil.

Every operation rewrites the whole file, so each takes a path rather than an open Database. The work builds a separate file and replaces the original only once that file is complete, so an interrupted operation leaves the original database as it was. The in place forms give the database a new identity on disk, which drops any hard link to it, and the database must not be in use.

Jet encoding is what ms access called "Encode/Decode Database" and removed after access 2003. It applies to .mdb files, it has no password, and its key is stored in the file, so it stops only a reader which does not know about it. A current ms access opens an encoded database and cannot add or remove the encoding.

Only jet 4 can be altered. Adding or removing the encoding rewrites the database, and jackcess does not write jet 3. An encoded jet 3 database still reads through CryptCodecProvider, which needs no change to the file.

Jet encoding and the jet database password are independent, and this class leaves the password alone in both directions. To have both, call PasswordUtil as well, in either order.

Author:

James Ahlborn

Method Summary

Modifier and Type	Method	Description
static void	addJetEncoding(Path dbFile)	Adds jet encoding to the given database, under a freshly generated key, replacing the file with the result.
static void	addJetEncoding(Path srcFile, Path dstFile)	Writes an encoded copy of the given database, under a freshly generated key, leaving the source alone.
static void	addOfficeAgileEncryption(Path dbFile, String password)	Encrypts the given .accdb database with agile encryption, replacing the file with the result.
static void	addOfficeAgileEncryption(Path dbFile, String password, AgileEncryptionConfig config)	Encrypts the given .accdb database with agile encryption under the given algorithms, replacing the file with the result.
static void	addOfficeAgileEncryption(Path srcFile, Path dstFile, String password)	Writes an agile encrypted copy of the given .accdb database, leaving the source alone.
static void	addOfficeAgileEncryption(Path srcFile, Path dstFile, String password, AgileEncryptionConfig config)	Writes a copy of the given .accdb database encrypted under the given algorithms, leaving the source alone.
static void	removeJetEncoding(Path dbFile)	Removes the jet encoding from the given database, replacing the file with the result.
static void	removeJetEncoding(Path srcFile, Path dstFile)	Writes a plain copy of the given encoded database, leaving the source alone.
static void	removeOfficeEncryption(Path dbFile, String password)	Removes the encryption from the given .accdb database, replacing the file with the result.
static void	removeOfficeEncryption(Path srcFile, Path dstFile, String password)	Writes a decrypted copy of the given .accdb database, leaving the source alone.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

addOfficeAgileEncryption

public static void addOfficeAgileEncryption(Path dbFile,
                                            String password)
                                     throws IOException

Encrypts the given .accdb database with agile encryption, replacing the file with the result. Agile is what a current ms access writes, and AgileEncryptionConfig.OFFICE_2010 is the profile it chooses.

Parameters:

dbFile - the plain database, not in use

password - the password to encrypt it with, not empty

Throws:

IllegalStateException - if it is already encrypted

IOException

addOfficeAgileEncryption

public static void addOfficeAgileEncryption(Path dbFile,
                                            String password,
                                            AgileEncryptionConfig config)
                                     throws IOException

Encrypts the given .accdb database with agile encryption under the given algorithms, replacing the file with the result.

Throws:

IOException

addOfficeAgileEncryption

public static void addOfficeAgileEncryption(Path srcFile,
                                            Path dstFile,
                                            String password)
                                     throws IOException

Writes an agile encrypted copy of the given .accdb database, leaving the source alone.

Throws:

IOException

addOfficeAgileEncryption

public static void addOfficeAgileEncryption(Path srcFile,
                                            Path dstFile,
                                            String password,
                                            AgileEncryptionConfig config)
                                     throws IOException

Writes a copy of the given .accdb database encrypted under the given algorithms, leaving the source alone.

Throws:

IOException

removeOfficeEncryption

public static void removeOfficeEncryption(Path dbFile,
                                          String password)
                                   throws IOException

Removes the encryption from the given .accdb database, replacing the file with the result.

Every scheme CryptCodecProvider can read is supported, which is agile and the older ones alike. Extensible encryption is the exception, because it delegates to an external provider and cannot be read at all.

The format version is left as it is. Ms access raises it when it writes agile encryption and does not lower it again when the encryption is removed, so a decrypted database keeps the raised version.

Parameters:

dbFile - the encrypted database, not in use

password - the password it was encrypted with

Throws:

IllegalStateException - if it is not encrypted

InvalidCredentialsException - if the password is wrong

IOException

removeOfficeEncryption

public static void removeOfficeEncryption(Path srcFile,
                                          Path dstFile,
                                          String password)
                                   throws IOException

Writes a decrypted copy of the given .accdb database, leaving the source alone.

Parameters:

srcFile - the encrypted database

dstFile - where to write it, overwritten if it exists

password - the password the source was encrypted with

Throws:

IllegalStateException - if the source is not encrypted

InvalidCredentialsException - if the password is wrong

IOException

addJetEncoding

public static void addJetEncoding(Path dbFile)
                           throws IOException

Adds jet encoding to the given database, under a freshly generated key, replacing the file with the result.

Parameters:

dbFile - the jet 4 database to encode, not in use

Throws:

IllegalStateException - if it is already encoded

IOException

addJetEncoding

public static void addJetEncoding(Path srcFile,
                                  Path dstFile)
                           throws IOException

Writes an encoded copy of the given database, under a freshly generated key, leaving the source alone.

Parameters:

srcFile - the jet 4 database to encode

dstFile - where to write it, overwritten if it exists

Throws:

IllegalStateException - if the source is already encoded

IOException

removeJetEncoding

public static void removeJetEncoding(Path dbFile)
                              throws IOException

Removes the jet encoding from the given database, replacing the file with the result.

Parameters:

dbFile - the encoded jet 4 database, not in use

Throws:

IllegalStateException - if it is not encoded

IOException

removeJetEncoding

public static void removeJetEncoding(Path srcFile,
                                     Path dstFile)
                              throws IOException

Writes a plain copy of the given encoded database, leaving the source alone.

Parameters:

srcFile - the encoded jet 4 database

dstFile - where to write it, overwritten if it exists

Throws:

IllegalStateException - if the source is not encoded

IOException