Package org.syncany.crypto

Class CipherSpecs

java.lang.Object

org.syncany.crypto.CipherSpecs

public class CipherSpecs
extends java.lang.Object

Defines and identifies the application supported CipherSpecs.

These cipher specs are used by the MultiCipherOutputStream to encrypt data, and by the MultiCipherInputStream to decrypt data. The cipher spec identifiers are used in the crypto format header to identify the crypto algorithms used for encryption.

The class defines a well defined (and developer-approved) set of allowed cipher algorithms, modes and key sizes. The number of allowed ciphers is greatly restricted to follow the application-specific security standards. Most prominently, this includes:

• The block cipher mode must be authenticated (GCM, EAX, etc.). Unauthenticated modes are not supported and will be rejected by the CipherSpec sanity checks.
• The block cipher mode must require an initialization vector (IV). Modes that do not require an IV (e.g. ECB) will be rejected by the CipherSpec sanity checks.

Field Summary

Fields

Modifier and Type	Field	Description
static int	AES_128_GCM
static int	AES_256_GCM
static int[]	DEFAULT_CIPHER_SPECS
static int	TWOFISH_128_GCM
static int	TWOFISH_256_GCM

Constructor Summary

Constructors

Constructor	Description
CipherSpecs()

Method Summary

Modifier and Type	Method	Description
static java.util.Map<java.lang.Integer,CipherSpec>	getAvailableCipherSpecs()	Returns a list of available/registered CipherSpecs.
static CipherSpec	getCipherSpec(int id)	Retrieves an available/registered CipherSpec using the cipher spec identifier defined in this class.
static java.util.List<CipherSpec>	getDefaultCipherSpecs()	Returns the default CipherSpecs used by the application.
static void	registerCipherSpec(int id, CipherSpec cipherSpec)	Register a new cipher spec.

Methods inherited from class java.lang.Object

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

Field Detail

AES_128_GCM

public static final int AES_128_GCM

See Also:

Constant Field Values

TWOFISH_128_GCM

public static final int TWOFISH_128_GCM

See Also:

Constant Field Values

AES_256_GCM

public static final int AES_256_GCM

See Also:

Constant Field Values

TWOFISH_256_GCM

public static final int TWOFISH_256_GCM

See Also:

Constant Field Values

DEFAULT_CIPHER_SPECS

public static final int[] DEFAULT_CIPHER_SPECS

Constructor Detail

CipherSpecs

public CipherSpecs()

Method Detail

getAvailableCipherSpecs

public static java.util.Map<java.lang.Integer,CipherSpec> getAvailableCipherSpecs()

Returns a list of available/registered CipherSpecs. Refer to the class description for a more detailed explanation.

getDefaultCipherSpecs

public static java.util.List<CipherSpec> getDefaultCipherSpecs()

Returns the default CipherSpecs used by the application.

getCipherSpec

public static CipherSpec getCipherSpec(int id)

Retrieves an available/registered CipherSpec using the cipher spec identifier defined in this class.

Parameters:

id - Identifier of the cipher spec

Returns:

A cipher spec, or null if no cipher spec with this identifier is registered

registerCipherSpec

public static void registerCipherSpec(int id,
                                      CipherSpec cipherSpec)

Register a new cipher spec.

Note: Registering a cipher spec locally does not make it available on all clients. Unless a cipher spec is registered before a client tries to decrypt data using the MultiCipherInputStream, the decryption process will fail.

Parameters:

id - Identifier of the cipher spec