Three building blocks for a complete infrastructure.
Gankpo rests on three independent but complementary technical blocks: a self-contained file format, an identity model aligned with the work of the W3C and the EUDI Wallet, and a multi-platform software ecosystem sharing a single Rust cryptographic core.
The .gkp format, a self-contained electronic original.
A .gkp file is not just a signed document. It is a binary container that carries, alongside the content itself, the full set of proofs required to verify it: cryptographic digest, signatures, issuer certificates, timestamp, and any co-signature chain.
This self-sufficiency has a decisive operational consequence: verification can happen offline, on any workstation equipped with a Gankpo reader, without contacting any remote server. A document signed today will still be verifiable ten years from now, in any administration, however remote.
Binary structure: magic bytes GKP2, 64-byte header, canonical CBOR metadata (RFC 8949), AEAD envelope (ChaCha20-Poly1305 or AES-256-GCM), appendable Ed25519 multi-signature chain.
Two-level identity: holder, issuer, verifier.
Gankpo relies on a widely recognised model: theholder – issuer – verifier model, formalised by the W3C and adopted by the European Union's EUDI Wallet architectural framework.
Three roles, three responsibilities:
- The issuer — typically a state authority — emits a credential signed with its certification key.
- The holder — the citizen or the organisation — keeps this credential in their mobile wallet, under their exclusive control.
- The verifier — an officer, an administrative counterpart, an employer — validates the credential without contacting the issuer, thanks to the national trust registry.
This trust registry is controlled by the adopting institution, which decides which issuers are recognised on its perimeter. The architecture decouples the act of verification from the software publisher: nobody other than the institution concerned can grant or revoke that trust.
A multi-platform ecosystem, a single core.
Digital trust does not live in a single application. It must be available wherever usage takes place: at an administration desk, in the field with a mobile officer, in a citizen's smartphone, in the API of a SaaS vendor who integrates Gankpo into their own flows, in the command line of a technical integrator.
That is why the Gankpo ecosystem covers desktop, mobile, tablet, command line, and API integration. Every application shares the same Rust cryptographic core, which guarantees strict consistency of formats and verifications across all channels.
Explore the full ecosystem.
Eight applications covering every use of digital trust — from the citizen to the ministry.