Accept new key
===20===
decryptedMessageActionAcceptKey#6fe1735b exchange_id:long g_b:bytes key_fingerprint:long = DecryptedMessageAction;| Name | Type | Description | 
|---|---|---|
| exchange_id | long | Exchange ID | 
| g_b | bytes | B parameter, see rekeying process | 
| key_fingerprint | long | Key fingerprint, see rekeying process |