# `CCXT.WS.Auth.JsonrpcLinebreak`
[🔗](https://github.com/ZenHive/ccxt_client/blob/main/lib/ccxt/ws/auth/jsonrpc_linebreak.ex#L1)

JSON-RPC Linebreak auth pattern — deribit.

Signs `"{timestamp_ms}\n{nonce}\n"` with HMAC-SHA256 hex and wraps the
signature in a JSON-RPC 2.0 `public/auth` frame with
`grant_type: "client_signature"`.

`handle_auth_response/2` extracts `result.expires_in` (seconds) and returns
`{:ok, %{ttl_ms: N}}` so the adapter can schedule re-auth via
`CCXT.WS.Auth.Expiry`.

## Example Frame (deribit)

    %{
      "jsonrpc" => "2.0",
      "id" => 1,
      "method" => "public/auth",
      "params" => %{
        "grant_type" => "client_signature",
        "client_id" => "api_key",
        "timestamp" => 1699999999999,
        "signature" => "hex_signature",
        "nonce" => "1699999999999",
        "data" => ""
      }
    }

## Config / opts

| Key | Location | Default | Purpose |
|---|---|---|---|
| `:method_value` | `config` | `"public/auth"` | RPC method override |
| `:nonce` | `opts` | `to_string(timestamp)` | Explicit nonce |
| `:request_id` | `opts` | `System.unique_integer([:positive])` | RPC `id` |
| `:timestamp_ms_override` | `config` | (unset) | Test-only — freezes the clock |
| `:nonce_override` | `config` | (unset) | Test-only — freezes the nonce |

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*Consult [api-reference.md](api-reference.md) for complete listing*