@startuml
skinparam monochrome true
skinparam defaultFontName Arial
skinparam classFontSize 10
skinparam sequenceBoxBorderColor #black
participant "**Accessor Authentication Service**" as aas 
participant "**Accessor Authentication Application**" as aaa 
autonumber
...
aas->aaa: aChallenge 
note right
[eSK.AAA.ECKA,ePK.AAA.ECKA]=ECDHE()
Certification_Path<sub>ATK_AAA</sub>=
   GENTOKEN(Certification_Path<sub>AAA</sub>,eSK.AAA.ECKA,ePK.AAA.ECKA)
end note
...  
aaa->aas: Certification_Path<sub>ATK_AAA</sub> 
activate aas
note left of aas
VERIFY_PATH(PK.CI<sub>AAA</sub>.ECDSA)[Certification_Path<sub>AAA</sub>]
[eSK.AAS.ECKA,ePK.AAS.ECKA]=ECDHE()
Certification_Path<sub>ATK_AAS</sub>=
   GENTOKEN(Certification_Path<sub>AAS</sub>,eSK.AAS.ECKA,ePK.AAS.ECKA)
<b>ShS</b>=ECKA-DH(eSK.AAS.ECKA,ePK.AAA.ECKA)
end note
activate aaa
aas-->aaa: Certification_Path<sub>ATK_AAS</sub>  
deactivate aaa
deactivate aas
aaa->aaa
activate aaa
note right of aaa
VERIFY_PATH(PK.CI<sub>AAS</sub>.ECDSA)[Certification_Path<sub>ATK_AAS</sub>]
<b>ShS</b>=ECKA-DH(eSK.AAA.ECKA,ePK.AAS.ECKA) 
end note
deactivate aaa
@enduml