@spec decode_attestation_object(binary()) :: {:ok, map()} | {:error, term()}

Decodes a CBOR-encoded attestation object.

Examples

iex> ExSwan.CBORUtils.decode_attestation_object(cbor_data)
{:ok, %{
  "fmt" => "packed",
  "authData" => <<...>>,
  "attStmt" => %{...}
}}

@spec decode_attestation_object_from_base64(binary()) ::
  {:ok, map()} | {:error, term()}

Decodes a base64url-encoded CBOR attestation object.

This function is used when the attestation object comes from client as base64url.

@spec decode_credential_public_key(binary()) :: {:ok, map()} | {:error, term()}

Decodes a CBOR-encoded credential public key.

Returns a map containing the public key parameters according to RFC 8152 (CBOR Object Signing and Encryption).

Includes workaround for Firefox 117 EdDSA CBOR encoding bug.

Examples

iex> ExSwan.CBORUtils.decode_credential_public_key(cbor_data)
{:ok, %{
  1 => 2,    # kty (Key Type): EC2
  3 => -7,   # alg (Algorithm): ES256
  -1 => 1,   # crv (Curve): P-256
  -2 => x_coordinate,
  -3 => y_coordinate
}}

@spec decode_extensions(binary()) :: {:ok, map()} | {:error, term()}

Decodes CBOR-encoded authenticator data extensions.

@spec encode_attestation_object(map()) :: {:ok, binary()} | {:error, term()}

Encodes an attestation object map to CBOR format.

@spec encode_credential_public_key(map()) :: {:ok, binary()} | {:error, term()}

Encodes a credential public key map to CBOR format.

@spec encode_extensions(map()) :: {:ok, binary()} | {:error, term()}

Encodes extensions map to CBOR format.

@spec validate_attestation_object(map()) :: :ok | {:error, atom()}

Validates that a decoded CBOR map contains expected WebAuthn fields.

Examples

iex> ExSwan.CBORUtils.validate_attestation_object(%{"fmt" => "packed", "authData" => <<...>>})
:ok

iex> ExSwan.CBORUtils.validate_attestation_object(%{"invalid" => "data"})
{:error, :missing_required_fields}

@spec validate_public_key(map()) :: :ok | {:error, atom()}

Validates that a decoded public key contains expected COSE key fields.