Package net.i2p.crypto

Class SessionKeyManager

  • Direct Known Subclasses:
    MuxedSKM, RatchetSKM, TransientSessionKeyManager
    public class SessionKeyManager
extends Object
    Manage the session keys and session tags used for encryption and decryption. This base implementation simply ignores sessions and acts as if everything is unknown (and hence always forces a full ElGamal encryption for each message). See TransientSessionKeyManager subclass which manages and persists keys and tags.

    • Constructor Detail

      • SessionKeyManager

        public SessionKeyManager()
        A dummy SessionKeyManager for testing or for passing to ElGamalAESEngine.decrypt()
        Since:
        0.9.14

      • SessionKeyManager

        public SessionKeyManager​(I2PAppContext context)
        A dummy SessionKeyManager for testing or for passing to ElGamalAESEngine.decrypt()
        Parameters:
        context - unused
        Since:
        public since 0.9.14; protected before that

    • Method Detail

      • getCurrentKey

        public SessionKey getCurrentKey​(PublicKey target)
        Retrieve the session key currently associated with encryption to the target, or null if a new session key should be generated. Warning - don't generate a new session if this returns null, it's racy, use getCurrentOrNewKey()

      • getCurrentOrNewKey

        public SessionKey getCurrentOrNewKey​(PublicKey target)
        Retrieve the session key currently associated with encryption to the target. Generates a new session and session key if not previously exising.
        Returns:
        non-null
        Since:
        0.9

      • createSession

        public void createSession​(PublicKey target,
                          SessionKey key)
        Associate a new session key with the specified target. Metrics to determine when to expire that key begin with this call. Racy if called after getCurrentKey() to check for a current session; use getCurrentOrNewKey() in that case.

      • createSession

        public SessionKey createSession​(PublicKey target)
        Generate a new session key and associate it with the specified target. Racy if called after getCurrentKey() to check for a current session; use getCurrentOrNewKey() in that case.

      • consumeNextAvailableTag

        public SessionTag consumeNextAvailableTag​(PublicKey target,
                                          SessionKey key)
        Retrieve the next available session tag for identifying the use of the given key when communicating with the target. If this returns null, no tags are available so ElG should be used with the given key (a new sessionKey should NOT be used)

      • getTagsToSend

        public int getTagsToSend()
        How many to send, IF we need to.
        Since:
        0.9.2

      • getLowThreshold

        public int getLowThreshold()
        Since:
        0.9.2

      • shouldSendTags

        public boolean shouldSendTags​(PublicKey target,
                              SessionKey key)
        Returns:
        true if we have less than the threshold or what we have is about to expire
        Since:
        0.9.2

      • shouldSendTags

        public boolean shouldSendTags​(PublicKey target,
                              SessionKey key,
                              int lowThreshold)
        Returns:
        true if we have less than the threshold or what we have is about to expire
        Since:
        0.9.2

      • getAvailableTags

        public int getAvailableTags​(PublicKey target,
                            SessionKey key)
        Determine (approximately) how many available session tags for the current target have been confirmed and are available

      • getAvailableTimeLeft

        public long getAvailableTimeLeft​(PublicKey target,
                                 SessionKey key)
        Determine how long the available tags will be available for before expiring, in milliseconds

      • tagsDelivered

        public TagSetHandle tagsDelivered​(PublicKey target,
                                  SessionKey key,
                                  Set<SessionTag> sessionTags)
        Take note of the fact that the given sessionTags associated with the key for encryption to the target have definitely been received at the target (aka call this method after receiving an ack to a message delivering them)

      • failTags

        public void failTags​(PublicKey target)
        Mark all of the tags delivered to the target up to this point as invalid, since the peer has failed to respond when they should have. This call essentially lets the system recover from corrupted tag sets and crashes

      • tagsReceived

        public void tagsReceived​(SessionKey key,
                         Set<SessionTag> sessionTags)
        Accept the given tags and associate them with the given key for decryption, with the default expiration.

      • tagsReceived

        public void tagsReceived​(SessionKey key,
                         Set<SessionTag> sessionTags,
                         long expire)
        Accept the given tags and associate them with the given key for decryption, with specified expiration.
        Parameters:
        sessionTags - modifiable; NOT copied
        expire - time from now
        Since:
        0.9.7

      • consumeTag

        public SessionKey consumeTag​(SessionTag tag)
        Determine if we have received a session key associated with the given session tag, and if so, discard it (but keep track for frequent dups) and return the decryption key it was received with (via tagsReceived(...)). returns null if no session key matches

      • shutdown

        public void shutdown()
        Called when the system is closing down, instructing the session key manager to take whatever precautions are necessary (saving state, etc)