# Centre for Digital Public Infrastructure (CDPI)

> CDPI is a global advisory centre housed at IIIT Bangalore that provides software-neutral technical architecture guidance to countries building population-scale digital public infrastructure (DPI) — spanning identity, payments, data sharing, credentials, and discovery networks. It operates across 40+ countries with 12 active pilots.

## About

- [What is DPI](https://docs.cdpi.dev/the-dpi-wiki/what-is-dpi): An approach to solving socio-economic problems at population scale by merging open technology standards with governance frameworks; real-world examples include India's Aadhaar, Brazil's Pix, Estonia's X-Road, Singapore's SingPass, and Thailand's PromptPay
- [DPI Overview](https://docs.cdpi.dev/the-dpi-wiki/dpi-overview): Five foundational categories — identifiers & registries, data sharing & AI/ML models, trust infrastructure (signatures & consent), discovery & fulfilment, and payments — inspired by how open standards (TCP-IP, HTTP, GSM) created the Internet and mobile networks
- [About CDPI](https://cdpi.dev/about-us/): Pro bono, philanthropically funded advisory centre; software-neutral, technology-neutral, government-neutral; team spans 5 countries and 3 continents
- [DPI Architecture Principles](https://docs.cdpi.dev/the-dpi-wiki/dpi-tech-architecture-principles): Five principles — (1) interoperability via open specs, (2) minimalist reusable building blocks, (3) diverse inclusive innovation via open APIs, (4) federated decentralised design, (5) security and privacy by design with tokenisation, consent, and encryption
- [Is My System a DPI?](https://docs.cdpi.dev/the-dpi-wiki/is-my-system-a-dpi): DPI maturity is a spectrum; requires open APIs/standards/specs, reusability by third parties, and adherence to all five architecture principles — open source alone does not make a system DPI

## Getting Started

- [First Use Case for DPI](https://docs.cdpi.dev/the-dpi-wiki/first-use-case-for-dpi): Pick use cases that are high-frequency ("toothbrush" use), cover large populations, and have ministry alignment; always pursue 3 use cases and 3 first adopters in parallel
- [How Much Does It Cost](https://docs.cdpi.dev/the-dpi-wiki/how-much-does-it-cost-to-build-dpi): Standards adoption in 3-4 weeks at negligible cost; conversion-based blocks ~$750K over 6 months; greenfield payment systems under $7M; DaaS program compresses 24-month rollouts to 8-12 weeks
- [Digital Transformation Strategy](https://docs.cdpi.dev/the-dpi-wiki/inputs-for-designing-a-dpi-informed-digital-transformation-strategy): Light-touch +1 interventions on existing systems — add signed QR code to physical ID for eAuth/eKYC, set common QR spec for wallet interoperability, add G2P mapper for benefit routing
- [DPI Implementation & Execution](https://docs.cdpi.dev/the-dpi-wiki/dpi-implementation-and-execution-guidance): 21 principles including small teams/high ownership, parallel phasing, design for failures, +1 thinking, don't charge on day 1, and asynchronous adoption over big-bang mandates
- [What DPI Can I Build?](https://docs.cdpi.dev/the-dpi-wiki/what-dpi-can-i-build): Role-specific guidance for central banks, ID departments, payment switches, health/agriculture/justice ministries, IT authorities, tax authorities, finance ministries, private banks, hospitals, and employers

## Technical Notes — Identity & Registries

- [Digital ID](https://docs.cdpi.dev/technical-notes/digital-ids-and-electronic-registries/digital-id): Any ID that is machine-readable, digitally signed, verifiable, and accessible online/offline qualifies; uniqueness is optional; convert existing IDs by adding signed QR codes and PKI — merging multiple IDs is not necessary
- [ID Authentication](https://docs.cdpi.dev/technical-notes/digital-ids-and-electronic-registries/digital-id/id-auth): Returns yes/no to "are you who you claim to be?" via demographic, biometric, face, or OTP modes; evaluate across proof type, self/assisted channels, and offline/online modes
- [eKYC / Identity Profile Sharing](https://docs.cdpi.dev/technical-notes/digital-ids-and-electronic-registries/digital-id/ekyc-identity-profile-sharing): Extends authentication by releasing minimum demographic fields and photo via API upon user consent; enables bank account opening, SIM KYC, government scheme enrollment
- [Single Sign-On](https://docs.cdpi.dev/technical-notes/digital-ids-and-electronic-registries/digital-id/single-sign-on-sso): Log into any public or private service using a government-issued ID (like "sign in with Google" but with national ID); supports OTP, biometric, and wallet-based auth
- [QR Code for Offline ID](https://docs.cdpi.dev/technical-notes/digital-ids-and-electronic-registries/digital-id/qr-code-for-offline-id): Compact signed payload (~2000 chars) for mid-range smartphones; supports versioning, key rotation, face matching with 3+ algorithms; 5-phase testing from lab to formal release
- [Face Authentication](https://docs.cdpi.dev/technical-notes/digital-ids-and-electronic-registries/digital-id/face-authentication): Mobile-first with liveness detection on edge devices; works online/offline with smart sync; enables assisted operators for digitally illiterate populations

## Technical Notes — Payments

- [Digital Payment Networks](https://docs.cdpi.dev/technical-notes/digital-payment-networks): Five key interventions — interoperable QR codes, interoperable authentication, financial address mapper, CICO agents, and bill payments; all transaction types powered by the same protocol across device types
- [G2P Payments](https://docs.cdpi.dev/technical-notes/digital-payment-networks/g2p-payments): Four building blocks — unique ID/eKYC layer, financial address mapper, last mile agents, and cross-functional registry network; architecture ensures interoperability, inclusion, and asynchronous adoption
- [Financial Address Mapper](https://docs.cdpi.dev/technical-notes/digital-payment-networks/financial-address): Maps IDs to financial accounts using format id-type:id@provider (e.g. mobile:12345@mobile-pymt, account:12345@national-bank); protects privacy, supports multiple stores of value; derived from India's UPI virtual address
- [Interoperable QR Code](https://docs.cdpi.dev/technical-notes/digital-payment-networks/interoperable-qr-code): Static and dynamic QR codes; spec v0.8.2 supports scan & pay, click & pay, deep linking, subscriptions, refunds, BNPL; includes digitally signed content for anti-phishing
- [Interoperable Authentication](https://docs.cdpi.dev/technical-notes/digital-payment-networks/interoperable-authentication-p2p-p2m): Three-layer separation — fintechs own UI, payment switch handles auth via standard SDK, banks settle; keeps funds in formal banking while enabling fintech innovation
- [Cash In Cash Out (CICO)](https://docs.cdpi.dev/technical-notes/digital-payment-networks/cash-in-cash-out-cico): Trained agents as micro-ATMs travel to remote areas; biometric auth via national ID enables deposit, withdraw, transfer, bill pay, balance check at no cost to users
- [Interoperable Bill Payments](https://docs.cdpi.dev/technical-notes/digital-payment-networks/interoperable-bill-payments): View and pay all bills through any app; back-end stays decentralised with billing authorities; issuers absorb minimal per-fetch cost

## Technical Notes — Data & Credentials

- [Data & Credentialing Infrastructure](https://docs.cdpi.dev/technical-notes/data-and-credentialing-infra): Data as digital capital — verifiable credentials, real-time consented data sharing, open anonymised datasets, and open AI/ML models for translation, underwriting, etc.
- [Verifiable Credentials](https://docs.cdpi.dev/technical-notes/data-and-credentialing-infra/verifiable-credentials): Tamper-proof certificates via digitally signed QR codes; three sharing modes — same-platform (DigiLocker model), separate consent manager (Account Aggregator model), or provider-managed; no centralisation needed; W3C-aligned
- [Personal Data Sharing Primer](https://docs.cdpi.dev/technical-notes/data-and-credentialing-infra/a-primer-to-personal-data-sharing): Three types — verifiable credentials via wallets, system-to-system in high-trust environments, and consent-led networks where users control data flow; cross-border credentials need no bilateral agreements
- [Data Standards](https://docs.cdpi.dev/technical-notes/data-and-credentialing-infra/data-standards): Guidelines ensuring syntax and semantics uniformity (e.g. ISO 10962, ICD 10, LOINC, Account Aggregator standards); multiple standards can co-exist if self-identifying; countries can extend global standards locally
- [eLockers](https://docs.cdpi.dev/technical-notes/data-and-credentialing-infra/elockers): Online verifiable digital document storage with decentralised control; fetches (not stores) data on consent; open APIs for issuers and requestors; India's Udyam MSME portal integrated in just 3 weeks
- [Non-Personal Anonymised Datasets](https://docs.cdpi.dev/technical-notes/data-and-credentialing-infra/non-personal-anonymised-datasets): Federated open data networks via protocols like Beckn; supports discovery, licensing, download, pricing, and update cycles; design principles — federation, privacy, open access, open standards

## Technical Notes — Signatures & Consent

- [Digital Signatures & PKI](https://docs.cdpi.dev/technical-notes/electronic-signature-pki-and-trust-infra/digital-signatures-and-pki): Private/public key pairs for signing and verifying data integrity; extends to websites, servers, and individual data fields within registries
- [eSign](https://docs.cdpi.dev/technical-notes/electronic-signature-pki-and-trust-infra/esign): Remote legally valid document signing built on ID authentication and eKYC APIs; enables an ecosystem of electronic signature providers as a service
- [eConsent](https://docs.cdpi.dev/technical-notes/electronic-signature-pki-and-trust-infra/econsent): Machine-readable consent artifacts specifying data provider, consumer, data types, access duration, frequency, and purpose; supports condition-based automatic approval for non-sensitive data

## Technical Notes — Discovery & Fulfillment

- [Discovery & Fulfillment Networks](https://docs.cdpi.dev/technical-notes/discovery-and-fulfillment-networks): Access any service or good across multiple apps interoperably — open APIs for government services, and shared protocols (Beckn) for mobility, eCommerce, financial services, health, and education
- [Platforms to Protocols](https://docs.cdpi.dev/technical-notes/discovery-and-fulfillment-networks/platforms-to-protocols): Current platform model creates data fragmentation, monopolies, and exclusion; DPI shifts to decentralised open networks where any app can discover any service on any platform

## Initiatives & Programs

- [DPI Advisory](https://docs.cdpi.dev/initiatives/dpi-advisory): Five neutralities (software, technology, financing, government, country); three engagement levels — conversational, co-creation, and roll-out action; contact info@cdpi.dev
- [DaaS — DPI as a Packaged Solution](https://docs.cdpi.dev/initiatives/daas): Three modules — open source + funded provider, artefacts only, or pre-trained vendor only; Cohort 1 offers digital authentication, digital credentials, and ID Account Mapper; install in under 8 hours, integrate in 1-3 weeks; DPI can also be built with proprietary software if it follows open specs
- [Funded DaaS Program](https://docs.cdpi.dev/initiatives/daas/funded-daas-program): Competitive 180-day program (90-day build + 90-day proof of concept); includes DaaS package, certified partners, cloud providers, and philanthropic funding; compresses traditional 24-month rollout
- [DPI Residents Program](https://docs.cdpi.dev/initiatives/dpi-residents-program): Embedded technical personnel in partner countries for sustained implementation support

## Specifications & Standards

- [Curated Global Specifications](https://docs.cdpi.dev/references/home): OAuth, OpenID, SAML for auth; ISO 20022 for payments; W3C for credentials; Beckn for discovery; MeitY/Govstack for consent; plus reference implementations (MOSIP, Mojaloop, OpenG2P, Sunbird, DHIS2, and more)
- [G2P Connect Specifications](https://g2p-connect.github.io/specs/): End-to-end social benefit payment protocol covering ID verification, beneficiary management, disbursement, and credentialing
- [Beckn Protocol](https://becknprotocol.io/): Open protocol for decentralised discovery and fulfilment across eCommerce, mobility, education (DSEP), and health (DHP)
- [W3C Verifiable Credentials](https://www.w3.org/TR/vc-data-model/): Data model, implementation guide, and API standard for tamper-proof credential issuance, presentation, and verification

## Optional

- [Learn — Mirra's DPI Journey](https://cdpi.dev/learn/): Interactive walkthrough of 12 DPI use cases — digital identity, payments, health records, financial inclusion, small-ticket loans, climate resilience, and G2P benefits — through a citizen's lifecycle from birth to old age
- [Read — Publications & Reports](https://cdpi.dev/read/): 50+ papers from CDPI, World Bank, IMF, Gates Foundation, UNDP, Carnegie Endowment, BIS, and others covering DPI economics, implementation, and country case studies
- [Watch — Videos & Masterclasses](https://cdpi.dev/watch/): Talks by Pramod Varma (India Stack architect), Nandan Nilekani (Aadhaar founding chairman), and practitioners covering DPI fundamentals, DaaS, open finance, and digital governance
- [Building a SuperApp](https://docs.cdpi.dev/the-dpi-wiki/building-a-superapp-a-three-step-guide-to-apply-dpi-thinking): A government SuperApp is NOT DPI by itself; success requires microservices architecture, federated data, layered ecosystem design, user control, and private innovation via open APIs
- [DPG and DPI](https://docs.cdpi.dev/the-dpi-wiki/dpg-and-dpi): DPGs are open-source software (e.g. MOSIP, OpenG2P, Mojaloop); DPI is the infrastructure approach — DPI can be built with DPGs, proprietary software, or hybrid, as long as it follows open specifications and architecture principles