# Svc::Ccsds::ClearTextDecryptor

> [!WARNING]
> **This component provides NO security.** It performs no authentication, no integrity
> checking, and no decryption. All data passes through unmodified. It is intended only
> for clear-mode operation (e.g. as the default decryptor in a standard subtopology) and
> for testing. Do not use it where confidentiality, integrity, or authenticity of the
> data link is required.

The `Svc::Ccsds::ClearTextDecryptor` component is a pass-through implementation of the `Svc.Ccsds.CcsdsSdlsDecrypt` interface. It is a pure pass-through in both dimensions: requests received on `decryptIn` are forwarded out `decryptOut` with the buffer and context unmodified (alongside an `SdlsStatus.SUCCESS` status), and buffer ownership returned on `decryptReturnIn` is passed upstream via `bufferReturnOut` for deallocation. No memory is allocated.

## Functionality

- Receives an SA index, iv/data buffer, and frame context on the guarded `decryptIn` port; the SA index is ignored.
- Forwards the buffer and context unmodified out `decryptOut` alongside an `SdlsStatus.SUCCESS` status.
- Passes ownership returns received on `decryptReturnIn` upstream via `bufferReturnOut` (the forwarded buffer is the incoming buffer, as no allocation occurs).

## Port Descriptions

| Kind          | Name            | Port Type                     | Description |
|---------------|-----------------|-------------------------------|-------------|
| guarded input | decryptIn       | Svc.Ccsds.CcsdsSdlsEncryption | Receives the SA index and iv/data buffer (from `CcsdsSdlsDecrypt` interface). |
| output        | decryptOut      | Svc.Ccsds.CcsdsSdlsData       | Sends the operation status and (unmodified) data downstream. |
| guarded input | decryptReturnIn | Svc.ComDataWithContext        | Receives back ownership of buffers sent on `decryptOut`. |
| output        | bufferReturnOut | Svc.ComDataWithContext        | Returns the incoming iv/data buffer for deallocation. |

## Requirements

| Name | Description | Validation |
|------|-------------|------------|
| SVC-CCSDS-CLEARTEXT-DECRYPTOR-001 | The ClearTextDecryptor shall accept an SA index, iv/data buffer, and frame context via the `Svc.Ccsds.CcsdsSdlsDecrypt` interface (guarded `decryptIn`). | Unit Test |
| SVC-CCSDS-CLEARTEXT-DECRYPTOR-002 | The ClearTextDecryptor shall perform no authentication and no decryption, passing the received buffer and context unmodified out `decryptOut`. | Unit Test |
| SVC-CCSDS-CLEARTEXT-DECRYPTOR-003 | The ClearTextDecryptor shall pass an `SdlsStatus.SUCCESS` status forward for every request. | Unit Test |
| SVC-CCSDS-CLEARTEXT-DECRYPTOR-004 | Upon receiving ownership of a buffer back on `decryptReturnIn`, the ClearTextDecryptor shall pass it upstream via `bufferReturnOut` for deallocation. | Unit Test |

## See Also

- [`Svc/Ccsds/Interfaces/CcsdsSdlsDecrypt.fpp`](../../Interfaces/CcsdsSdlsDecrypt.fpp)
- [`Svc/Ccsds/SdlsSaRouter`](../../SdlsSaRouter/docs/sdd.md)