Abstract: A method, of establishing secure communication, may include: generating a first symmetric key; encrypting at least the first symmetric key according to a public key; sending a first message that includes at least the encrypted first symmetric key to a communication counterpart using a connectionless protocol; and receiving, as part of a connection-oriented-protocol first session, a second message that includes an acknowledgement encrypted via the first symmetric key. A counterpart method may include: receiving and decrypting the first message according to the corresponding private key; and encrypting and then sending the second message. Another such method may include: encrypting a chunk of information according to a first symmetric key, the first symmetric key having been used in a previous and now-stopped connection-oriented session with a communication counterpart; and sending to a communication counterpart a first message whose payload at least in part the encrypted chunk of information.

Abstract: A method, of establishing secure communication, may include: generating a first symmetric key; encrypting at least the first symmetric key according to a public key; sending a first message that includes at least the encrypted first symmetric key to a communication counterpart using a connectionless protocol; and receiving, as part of a connection-oriented-protocol first session, a second message that includes an acknowledgement encrypted via the first symmetric key. A counterpart method may include: receiving and decrypting the first message according to the corresponding private key; and encrypting and then sending the second message. Another such method may include: encrypting a chunk of information according to a first symmetric key, the first symmetric key having been used in a previous and now-stopped connection-oriented session with a communication counterpart; and sending to a communication counterpart a first message whose payload at least in part the encrypted chunk of information.