⚠ SIMULATOR ONLY — NOT FOR PRODUCTION USE — All keys and values shown in cleartext

Callendina Visible Payments Explorer

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Network Simulation
HSM Functions

Visible Payments Explorer

An open, educational simulator for payment HSM cryptography and payment network message flows. All keys are shown in cleartext so you can see exactly what each operation does.

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Payment Network Simulation

Explore how terminals, acquirers, schemes and issuers communicate using AS2805 messages — for card issuance, PIN set, terminal provisioning and purchase transactions.

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HSM Functions

Step through individual HSM operations — generate LMKs and zone keys, encrypt PIN blocks, compute MACs, wrap keys with TR-31, and more. All inputs and outputs are visible.

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AS2805 • DUKPT • TR-31 • TR-34 • ISO 9797 • RSA — Educational use only
Business Processes
Network Topology
AS2805.6.2 AS2805.6.2 AS2805.6.3 AS2805.6.3 Terminal T1 Terminal T2 Terminal T3 Terminal T4 Acquirer AQ1 Acquirer AQ2 Acquirer AQ3 Scheme (SCH) Issuer ISS1 Issuer ISS2
Terminal (DUKPT SCD) Acquirer Scheme Issuer
All nodes use VisPayHSM. AS2805 messaging throughout. T1–T2: DUKPT/TDES • T3–T4: DUKPT/AES.
Business Process Detail
Select a business process from the left panel.

Select a function

Choose an HSM function from the sidebar to get started.

Save to Key Store