AttestoClient.DPoP (AttestoClient v2.9.0)

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Build DPoP proof JWTs (RFC 9449 §4), the client-side mirror of Attesto.DPoP.verify_proof/2.

A proof is a JWT, typed dpop+jwt, whose header carries the client's public key (as jwk) and whose payload binds the proof to a single HTTP request:

  • htm - the request method ("POST", "GET", ...), uppercased.
  • htu - the request URI with any query and fragment stripped (§4.2).
  • iat - issuance time.
  • jti - a unique identifier the server tracks against replay.
  • ath - base64url(SHA-256(access_token)), present only when the proof accompanies an access token (the resource-request leg, §4.2); it binds the proof to that token so a leaked proof cannot be paired with another.
  • nonce - a server-supplied DPoP nonce, echoed when the server has demanded one (a use_dpop_nonce error carrying a DPoP-Nonce header).

Signing and key-bound :alg/:kid validation are provided by Attesto.DPoP.Proof, keeping proof construction and verification on the same implementation. The proof's public jwk is this key, and the server pins the token to its jkt thumbprint.

Summary

Types

build_opt()
error()
jwk()

Functions

proof(jwk, htm, htu, opts \\ [])

Build a signed DPoP proof for a request to htu with method htm, returning {:ok, compact_jws} or {:error, reason}. Fails fast on invalid input.

Types

build_opt()

@type build_opt() ::
  {:access_token, String.t()}
  | {:nonce, String.t()}
  | {:alg, String.t()}
  | {:kid, String.t()}
  | {:now, integer() | DateTime.t()}
  | {:jti, String.t()}

error()

@type error() ::
  :invalid_key
  | :invalid_kid
  | :invalid_htm
  | :invalid_htu
  | :invalid_access_token
  | :invalid_nonce
  | :invalid_time
  | :invalid_jti
  | :unsupported_alg
  | :unsupported_key
  | {:signing_failed, String.t()}

jwk()

@type jwk() :: JOSE.JWK.t() | map()

Functions

proof(jwk, htm, htu, opts \\ [])

@spec proof(jwk(), String.t(), String.t(), [build_opt()]) ::
  {:ok, String.t()} | {:error, error()}

Build a signed DPoP proof for a request to htu with method htm, returning {:ok, compact_jws} or {:error, reason}. Fails fast on invalid input.

jwk is the DPoP key (private half required for signing). htm is the HTTP method and htu the target URI; the URI's query and fragment are stripped to form the htu claim. Pass :access_token on a resource request so the proof carries the ath binding, and :nonce to echo a server-demanded DPoP nonce. :alg, :kid, and :now behave as in AttestoClient.Wallet.Proof.build/2.