# `BoundedAuthorityProtocol.V1.BoundaryAnchor`
[🔗](https://github.com/baselabs/bounded_authority_protocol/blob/v1.0.0/lib/bounded_authority_protocol/v1/boundary_anchor.ex#L1)

Closed deterministic boundary-anchor signing input.

## Fields

* `anchor_id` - the anchor identity: non-empty StringOrURI of at most `identifier_bytes` (512)
  UTF-8 bytes.
* `anchored_at` - the anchor time, integer Unix time in seconds.
* `chain_id` - the chain identity: non-empty StringOrURI of at most `identifier_bytes` (512) UTF-8
  bytes.
* `sequence` - the anchored sequence number; `0` anchors an empty chain and requires a
  `chain_hash` of 32 zero bytes.
* `chain_hash` - the raw 32-byte chain hash at `sequence`.
* `key_id` - the signing key identifier, written to `kid`: 1 to `kid_bytes` (128) bytes of ASCII
  letters, digits, `-`, `.`, `_` or `~`.
* `public_key` - the signer's raw public key in the suite's fixed width: 32-byte Ed25519 under
  contract-majors 1 and 2, the 65-byte uncompressed SEC1 P-256 point `0x04 || x || y` under
  contract-major 3; the payload binds its RFC 7638 fingerprint.

# `t`

```elixir
@type t() :: %BoundedAuthorityProtocol.V1.BoundaryAnchor{
  anchor_id: binary(),
  anchored_at: integer(),
  chain_hash: binary(),
  chain_id: binary(),
  key_id: binary(),
  public_key: binary(),
  sequence: non_neg_integer()
}
```

Producer input for one boundary anchor.

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