Blind Issuance

Blind issuance lets the client obtain an issuer response without sending the final V4 input or V7 bearer artifact in the clear to the issuer.

V4 flow

The client creates its input, blinds it, and sends the blinded element to POST /v1/oprf/issue. After any configured admission proof passes, the issuer returns an evaluation. The client unblinds the evaluation and builds the final V4 redemption token bound to verifier scope.

V7 flow

The client constructs the canonical V7 body, including its body nullifier, and blinds the message with the randomized RSA suite. It sends the canonical 384-byte blinded message and explicit key ID to POST /v7/native-bearer/issue. The issuer returns one blind signature; the client finalizes the V7 token and later presents it to a verifier.

V7 exchange and graph issuance are optional durable operations, distinct from direct blind issuance. Their status capabilities are bearer secrets and must remain header-only; see Public Bearer Exchange.

Blindness does not remove operational metadata. IP addresses, timing, User-Agent data, logs, or an operator controlling both services can still enable correlation. Read the threat model before making privacy claims.