Crate spacedls 

spacedls

no_std implementation of CCSDS 355.0-B-2 and CCSDS 355.1-B-1 — Space Data Link Security (SDLS) protocol.

This crate provides the cryptographic framing layer defined by the Consultative Committee for Space Data Systems for securing telecommand (TC), telemetry (TM), Advanced Orbiting Systems (AOS) and Unified Space Data Link Protocol (USLP) transfer frames.

Standards

• CCSDS 355.0-B-2 — SDLS standard procedures
• CCSDS 355.1-B-1 — SDLS extended procedures

Feature flags

Flag	Default	Description
softcrypto	yes	Software AES-CBC, AES-GCM, and HMAC-SHA providers.
extended	yes	ManagedSa, ManagedKey lifecycle state machines, SA store, and Keyring proc macros.
std	no	Enables std (for testing / non-embedded targets).
defmt	no	Derives defmt::Format on public error and state types.

Architecture

The central type is SecurityAssociation, parameterized over a service provider, a frame format, and a counter-length:

SecurityAssociation<'a, S, F, N>
  'a — key lifetime
  S  — service wrapper (AsEnc, AsAuth, or AsAuthEnc)
  F  — SDLSFrameFormat (compile-time field lengths)
  N  — counter array size (sequence number or IV-as-counter)

Three service kinds map to CCSDS 355.0-B-2 Section 2.3.1.3:

• Encryption-only (AsEnc) — confidentiality without authentication
• Authentication-only (AsAuth) — integrity via MAC, no encryption
• Authenticated encryption (AsAuthEnc) — confidentiality + integrity (AEAD)

Frame formats are defined at the type level via SDLSFrameFormat. Each associated type (SNLen, IVLen, PLLen, MacLen, HeaderLen) is a typenum unsigned integer, enforced at compile time to be within valid CCSDS ranges.

Quick start

use spacedls::consts::{BIT128, BYTE0, BYTE4, BYTE12, BYTE16, BYTE18};
use spacedls::crypto::{AesGcm, VerifyMacResult};
use spacedls::key::ConstKey;
use spacedls::protocol::{SDLSFrameFormat, SecurityAssociation};
use spacedls::service::AsAuthEnc;

// Define a frame format matching your mission's SDLS configuration
struct MyFmt;
impl SDLSFrameFormat for MyFmt {
    type SNLen  = BYTE4;
    type IVLen  = BYTE12;
    type PLLen  = BYTE0;
    type MacLen = BYTE16;
    type HeaderLen = BYTE18; // 2 (SPI) + 12 (IV) + 4 (SN) + 0 (PL)
}

let key = ConstKey::<BIT128>::new([0u8; 16]);

let mut sa = SecurityAssociation::new_authenc(
    AesGcm::<aes::Aes128>::default(), 0x0001, &key, 16, None,
);

let iv = [0u8; 12].into();
let prefix = b"TC-HDR";
let plain = b"payload";
let mut cipher = [0u8; 7];
let (written, hdr, trlr) = sa.seal(iv, prefix, plain, &mut cipher).unwrap();

Modules

• consts — Byte/bit-width type aliases (BYTE4, BIT128, etc.)
• key — Key trait and implementations (ConstKey, EmptyKey, ManagedKey)
• service — Service provider traits and parameter types
• protocol — Frame format, security association, sequence numbers, errors
• crypto — MAC type and software crypto providers (feature-gated)

Modules

consts

Byte-width and bit-width type aliases for typenum unsigned integers.

crypto

MAC types and software cryptographic providers.

key

Cryptographic key abstractions.

protocol

SDLS protocol types: frame format, security association, sequence numbers, and errors.

service

Service provider traits and parameter types.

Macros

make_static_keyring

Generates a static, compile-time-fixed key ring struct.

make_static_sastore

Generates a static, compile-time-fixed SA store struct.