Payment Reference Guides
Deep-dive technical documentation covering ISO 8583, 3D Secure authentication, payment tokenization, and settlement mechanics.
ISO 8583 Protocol
Message structure, bitmap mechanics, 128 data elements, network variations
Read Guide →3D Secure (EMV 3DS)
Authentication flows, message types, ECI values, SCA exemptions
Read Guide →Payment Tokenization
FPAN→DPAN lifecycle, VTS vs MDES, TAVV cryptograms
Read Guide →Settlement & Clearing
Clearing files, net settlement, dispute timelines, interchange economics
Read Guide →TR-31 & TR-34 Key Standards
Key block format, RSA transport protocol, 2-pass & 1-pass flows, CMS token structure, HSM key lifecycle
Read Guide →Crypto Payment Protocols
Bitcoin & Lightning, Ethereum/EVM, Solana Pay, stablecoins — deep dives, URIs, and cross-protocol comparison
Read Guide →x402 Payment Protocol
HTTP 402 as a payment rail: the quote/sign/verify/settle handshake, PAYMENT-* headers, EIP-3009 authorizations, facilitators & the Bazaar — mapped to card-rails concepts
Read Guide →Open Banking & PSD2
AISP/PISP roles, consent & SCA flows, FAPI security, UK Open Banking, Berlin Group & STET
Read Guide →UnionPay Kernel 7
QuickPass contactless: TTQ/CTQ bit layouts, Fast DDA (fDDA), the CTQ-driven CVM decision, and UnionPay-specific tags
Read Guide →EMV Contactless Kernels 2–8
Kernel hierarchy & structural dependency, the runtime tap sequence, and convergence to Kernel 8 — plus per-kernel guides: Mastercard (K2), Visa (K3), Amex (K4), JCB (K5), Discover (K6), UnionPay (K7) and the common Kernel 8
Browse Kernels →Contactless Features: RRP, DS & MSD
Cross-kernel capabilities: Relay Resistance Protocol (anti-relay timing), Data Storage containers, and legacy mag-stripe mode with dynamic CVC3
Read Guide →MIFARE Family & Use Cases
Classic, Ultralight, Plus, DESFire & DUOX — the Crypto1 break and 2024 backdoor, use cases from transit and access control to EV charging, and a product-fit matrix
Read Guide →Post-Quantum Payments
What quantum computing breaks in payment crypto — EMV ODA, TR-34, TLS — vs what survives; ML-KEM / ML-DSA size budgets, and the 2026–2035 migration plan for HSM estates
Read Guide →EUDI Wallet & Payments
eIDAS 2.0 for payment engineers: the 2026/2027 deadlines, the SD-JWT VC / mdoc / OID4VP credential stack, and how PSD2 SCA with dynamic linking runs through the wallet
Read Guide →Nasdaq Calypso
Cross-asset, front-to-back capital markets & treasury platform: architecture, asset coverage, the trade lifecycle it automates, and where it fits versus payment rails
Read Guide →SWIFT Blockchain Shared Ledger
SWIFT's EVM/Hyperledger Besu orchestration layer for 24/7 tokenised-deposit settlement: architecture, payment flow, the 2026 17-bank pilot, and a stablecoin comparison
Read Guide →Country Payment Profiles
Dominant schemes, contactless limits, local networks, and regulatory notes for 20 key markets
Browse Countries →