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Decentralized Instant Messaging (Java SDK)
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/* license: https://mit-license.org
*
* DIM-SDK : Decentralized Instant Messaging Software Development Kit
*
* Written in 2019 by Moky
*
* ==============================================================================
* The MIT License (MIT)
*
* Copyright (c) 2019 Albert Moky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
* ==============================================================================
*/
package chat.dim;
import chat.dim.crypto.SymmetricKey;
import chat.dim.protocol.ID;
import chat.dim.protocol.Message;
public interface CipherKeyDelegate {
/* Situations:
+-------------+-------------+-------------+-------------+
| receiver | receiver | receiver | receiver |
| is | is | is | is |
| | | broadcast | broadcast |
| user | group | user | group |
+-------------+-------------+-------------+-------------+-------------+
| | A | | | |
| +-------------+-------------+-------------+-------------+
| group | | B | | |
| is |-------------+-------------+-------------+-------------+
| null | | | C | |
| +-------------+-------------+-------------+-------------+
| | | | | D |
+-------------+-------------+-------------+-------------+-------------+
| | E | | | |
| +-------------+-------------+-------------+-------------+
| group | | | | |
| is |-------------+-------------+-------------+-------------+
| broadcast | | | F | |
| +-------------+-------------+-------------+-------------+
| | | | | G |
+-------------+-------------+-------------+-------------+-------------+
| | H | | | |
| +-------------+-------------+-------------+-------------+
| group | | J | | |
| is |-------------+-------------+-------------+-------------+
| normal | | | K | |
| +-------------+-------------+-------------+-------------+
| | | | | |
+-------------+-------------+-------------+-------------+-------------+
*/
/**
* get destination for cipher key vector: (sender, dest)
*/
static ID getDestination(Message msg) {
ID receiver = msg.getReceiver();
ID group = ID.parse(msg.get("group"));
return getDestination(receiver, group);
}
static ID getDestination(ID receiver, ID group) {
if (group == null && receiver.isGroup()) {
/// Transform:
/// (B) => (J)
/// (D) => (G)
group = receiver;
}
if (group == null) {
/// A : personal message (or hidden group message)
/// C : broadcast message for anyone
assert receiver.isUser() : "receiver error: " + receiver;
return receiver;
}
assert group.isGroup() : "group error: " + group + ", receiver: " + receiver;
if (group.isBroadcast()) {
/// E : unencrypted message for someone
// return group as broadcast ID for disable encryption
/// F : broadcast message for anyone
/// G : (receiver == group) broadcast group message
assert receiver.isUser() || receiver.equals(group) : "receiver error: " + receiver;
return group;
} else if (receiver.isBroadcast()) {
/// K : unencrypted group message, usually group command
// return receiver as broadcast ID for disable encryption
assert receiver.isUser() : "receiver error: " + receiver + ", group: " + group;
return receiver;
} else {
/// H : group message split for someone
/// J : (receiver == group) non-split group message
return group;
}
}
/**
* Get cipher key for encrypt message from 'sender' to 'receiver'
*
* @param sender - from where (user or contact ID)
* @param receiver - to where (contact or user/group ID)
* @param generate - generate when key not exists
* @return cipher key
*/
SymmetricKey getCipherKey(ID sender, ID receiver, boolean generate);
/**
* Cache cipher key for reusing, with the direction (from 'sender' to 'receiver')
*
* @param sender - from where (user or contact ID)
* @param receiver - to where (contact or user/group ID)
* @param key - cipher key
*/
void cacheCipherKey(ID sender, ID receiver, SymmetricKey key);
}