@startuml
database Bitcoin
actor Bob
Actor Alice
database Monero

Bob --> Alice: Establish connection

group Request Response Channel
    Bob -> Alice: Request Amounts
    note left: Btc Amount

    Alice --> Bob: Send Amounts
    note right: Btc & Xmr Amounts
end

group Request Response Channel
    Bob -> Alice: bob::Message0
    note left: Pubkeys\ndleq proof s_b\nxmr viewkey v_b\nbtc refund addr

    Alice --> Bob: alice::Message0
    note right: Pubkeys\ndleq proof s_a\nxmr view key v_a\nbtc redeem addr\nbtc punish addr
end

group Request Response Channel
    Bob -> Alice: bob::Message1
    note left: btc lock tx

    Alice --> Bob: alice::Message1
    note right: cancel tx sig\nrefund tx enc sig S_b
end

group Request Response Channel
    Bob -> Alice: bob::Message2
    note left: punish tx sig\ncancel tx sig

== Negotiated ==

    Bob ->> Bitcoin: Lock

    Alice ->> Monero: Lock

    Alice --> Bob: alice::Message2
    note right: xmr lock tx transfer proof
end

    Bob -> Alice: bob::Message3
    note left: redeem tx enc sig S_a

    Alice ->> Bitcoin: Redeem

    Bitcoin ->> Bob: Signature

    Bob -> Bob: Extract s_a

    Bob ->> Monero: Redeem

@enduml