# `A2A.SecurityScheme`
[🔗](https://github.com/actioncard/a2a-elixir/blob/main/lib/a2a/security_scheme.ex#L1)

Union type over the five A2A security scheme types.

Each scheme maps to a discriminator key in the wire format:

- `"apiKeySecurityScheme"` → `%APIKey{}`
- `"httpAuthSecurityScheme"` → `%HTTPAuth{}`
- `"oauth2SecurityScheme"` → `%OAuth2{}`
- `"openIdConnectSecurityScheme"` → `%OpenIDConnect{}`
- `"mtlsSecurityScheme"` → `%MutualTLS{}`

# `t`

```elixir
@type t() ::
  A2A.SecurityScheme.APIKey.t()
  | A2A.SecurityScheme.HTTPAuth.t()
  | A2A.SecurityScheme.OAuth2.t()
  | A2A.SecurityScheme.OpenIDConnect.t()
  | A2A.SecurityScheme.MutualTLS.t()
```

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