org.whispersystems.libsignal.state

Interface IdentityKeyStore

All Known Subinterfaces:

SignalProtocolStore

All Known Implementing Classes:

InMemoryIdentityKeyStore, InMemorySignalProtocolStore

public interface IdentityKeyStore

Provides an interface to identity information.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	IdentityKeyStore.Direction

Method Summary

Modifier and Type	Method and Description
IdentityKey	getIdentity(SignalProtocolAddress address) Return the saved public identity key for a remote client
IdentityKeyPair	getIdentityKeyPair() Get the local client's identity key pair.
int	getLocalRegistrationId() Return the local client's registration ID.
boolean	isTrustedIdentity(SignalProtocolAddress address, IdentityKey identityKey, IdentityKeyStore.Direction direction) Verify a remote client's identity key.
boolean	saveIdentity(SignalProtocolAddress address, IdentityKey identityKey) Save a remote client's identity key

Method Detail

getIdentityKeyPair

IdentityKeyPair getIdentityKeyPair()

Get the local client's identity key pair.

Returns:

The local client's persistent identity key pair.

getLocalRegistrationId

int getLocalRegistrationId()

Return the local client's registration ID.

Clients should maintain a registration ID, a random number between 1 and 16380 that's generated once at install time.

Returns:

the local client's registration ID.

saveIdentity

boolean saveIdentity(SignalProtocolAddress address,
                     IdentityKey identityKey)

Save a remote client's identity key

Store a remote client's identity key as trusted.

Parameters:

address - The address of the remote client.

identityKey - The remote client's identity key.

Returns:

True if the identity key replaces a previous identity, false if not

isTrustedIdentity

boolean isTrustedIdentity(SignalProtocolAddress address,
                          IdentityKey identityKey,
                          IdentityKeyStore.Direction direction)

Verify a remote client's identity key.

Determine whether a remote client's identity is trusted. Convention is that the Signal Protocol is 'trust on first use.' This means that an identity key is considered 'trusted' if there is no entry for the recipient in the local store, or if it matches the saved key for a recipient in the local store. Only if it mismatches an entry in the local store is it considered 'untrusted.' Clients may wish to make a distinction as to how keys are trusted based on the direction of travel. For instance, clients may wish to accept all 'incoming' identity key changes, while only blocking identity key changes when sending a message.

Parameters:

address - The address of the remote client.

identityKey - The identity key to verify.

direction - The direction (sending or receiving) this identity is being used for.

Returns:

true if trusted, false if untrusted.

getIdentity

IdentityKey getIdentity(SignalProtocolAddress address)

Return the saved public identity key for a remote client

Parameters:

address - The address of the remote client

Returns:

The public identity key, or null if absent