Package com.healthmarketscience.jackcess.crypt.impl.office

Class AgileEncryptionWriter

java.lang.Object

com.healthmarketscience.jackcess.crypt.impl.office.AgileEncryptionWriter

public class AgileEncryptionWriter
extends Object

Builds the agile key material and the descriptor which carries it.

This is the inverse of AgileEncryptionProvider, which is what makes it testable without ms access: taking the salts out of a database ms access encrypted, decrypting its three wrapped values and encrypting them again has to give back the bytes ms access wrote.

Nothing here writes a dataIntegrity element. No .accdb ms access produced carries one, from 2007 to a current version, and the read path does not look for it.

Author:

James Ahlborn

Constructor Summary

Constructors

Constructor	Description
AgileEncryptionWriter(AgileEncryptionConfig config, String password)	Generates fresh key material for the given password.
AgileEncryptionWriter(AgileEncryptionConfig config, String password, byte[] keyDataSalt, byte[] pwdSalt, byte[] keyValue, byte[] verifierInput)	Uses the given key material rather than generating it, which is how the forward direction is checked against a database ms access wrote.

Method Summary

Modifier and Type	Method	Description
byte[]	createDescriptor()	Returns the descriptor xml, which is what page 0 carries after the version and the reserved value.
byte[]	encryptKeyValue()
static void	encryptPage(AgileEncryptionConfig config, byte[] keyValue, byte[] salt, byte[] blockBytes, byte[] pageBytes)	Encrypts one page under the content key.
byte[]	encryptVerifierHashInput()
byte[]	encryptVerifierHashValue()
byte[]	getKeyDataSalt()	Returns the salt which also serves as the page cipher IV base.
byte[]	getKeyValue()	Returns the key the pages are encrypted with.
byte[]	unwrapKeyValue(byte[] wrapped)	Reverses encryptKeyValue(), which is how the pair is checked.
byte[]	unwrapVerifierHashInput(byte[] wrapped)	Reverses encryptVerifierHashInput().

Methods inherited from class java.lang.Object

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

Constructor Detail

AgileEncryptionWriter

public AgileEncryptionWriter(AgileEncryptionConfig config,
                             String password)

Generates fresh key material for the given password.

AgileEncryptionWriter

public AgileEncryptionWriter(AgileEncryptionConfig config,
                             String password,
                             byte[] keyDataSalt,
                             byte[] pwdSalt,
                             byte[] keyValue,
                             byte[] verifierInput)

Uses the given key material rather than generating it, which is how the forward direction is checked against a database ms access wrote.

Method Detail

getKeyValue

public byte[] getKeyValue()

Returns the key the pages are encrypted with.

getKeyDataSalt

public byte[] getKeyDataSalt()

Returns the salt which also serves as the page cipher IV base.

encryptVerifierHashInput

public byte[] encryptVerifierHashInput()

encryptVerifierHashValue

public byte[] encryptVerifierHashValue()

unwrapKeyValue

public byte[] unwrapKeyValue(byte[] wrapped)

Reverses encryptKeyValue(), which is how the pair is checked.

unwrapVerifierHashInput

public byte[] unwrapVerifierHashInput(byte[] wrapped)

Reverses encryptVerifierHashInput().

encryptKeyValue

public byte[] encryptKeyValue()

createDescriptor

public byte[] createDescriptor()

Returns the descriptor xml, which is what page 0 carries after the version and the reserved value.

encryptPage

public static void encryptPage(AgileEncryptionConfig config,
                               byte[] keyValue,
                               byte[] salt,
                               byte[] blockBytes,
                               byte[] pageBytes)

Encrypts one page under the content key. The IV comes from the key data salt and the block bytes, which are the encoding key xored with the page number, so every page gets its own IV without moving any data.