crystal-crypto-samples v0.3.0

End-to-end integration harness and demonstration suite for the EVALinux Crypto Suite (CBOR FIDO, ECC Constant, PQC Constant, DBus Native, and TPM2 TSS).

GitLab Project Metadata:

• Description: End-to-end integration harness and demonstration suite for the EVALinux Crypto Suite (CBOR FIDO, ECC Constant, PQC Constant, DBus Native, and TPM2 TSS).
• Topics and Tags: crystal, crystal-lang, cryptography, post-quantum-cryptography, fido2, tpm2, dbus, cbor, ed25519, ml-kem, ml-dsa, gplv3

The Crypto Suite Shards

This sample application dynamically links and demonstrates the capabilities of our five standalone shards:

• Crystal CBOR FIDO (~> 0.2.2): Memory-safe Canonical CBOR (RFC 8949 §4.2/CTAP2 §6) encoder and decoder with canonical IEEE 754 float narrowing, COSE/WebAuthn structures, and trailing-byte rejection.
• Crystal DBus Native (~> 0.3.1): Native, zero-dependency D-Bus wire protocol featuring general-purpose BodyCodec (Variant, StructValue, a{sv}), HeaderCodec, SASL EXTERNAL authentication, and SCM_RIGHTS file descriptor passing.
• Crystal ECC Constant (~> 0.2.2): Strictly constant-time classical Elliptic Curve Cryptography (Ed25519, Ed25519ph, X25519 ECDH, and BLAKE2b KDF) backed by libsodium secure memory and sodium_mprotect_readonly page protection.
• Crystal PQC Constant (~> 0.1.1): Constant-time Post-Quantum Cryptography implementing NIST FIPS 203 ML-KEM (ML-KEM-512, ML-KEM-768, ML-KEM-1024) and NIST FIPS 204 ML-DSA (ML-DSA-44, ML-DSA-65, ML-DSA-87) backed by OpenSSL 3.5+ EVP_PKEY and libsodium guarded memory.
• Crystal TPM2 TSS (~> 0.4.1): Native TPM 2.0 Software Stack featuring hardware NV storage key persistence, real OpenSSL 3.5 NIST P-256 key generation and ECDSA verification (TPM2_ReadPublic), KDFa XOR and AES-128-CFB parameter encryption, TCG cpHash/rpHash calculation, and $\mathcal{O}(1)$ atomic nonce-reuse detection.

Post-Quantum Cryptography in the Suite

Post-Quantum Cryptography (PQC) is provided as a dedicated, standalone shard—crystal-pqc-constant—and demonstrated directly in CrystalCryptoSamples.run_pqc_sample, run_hybrid_pqc_sample, and run_ctap2_dbus_sample:

• Why PQC Is Required: Classical public-key algorithms (Ed25519 and X25519 in crystal-ecc-constant, as well as hardware-bound NIST P-256 in crystal-tpm2-tss) rely on the hardness of the Elliptic Curve Discrete Logarithm Problem (ECDLP). A Cryptographically Relevant Quantum Computer (CRQC) executing Shor's algorithm can solve ECDLP in polynomial time, threatening both historical key-agreement transcripts ("harvest now, decrypt later") and long-lived digital signatures.
• NIST FIPS 203 ML-KEM Key Encapsulation: Crystal::Pqc::Constant::MLKEMKeyPair implements Module-Lattice-Based Key-Encapsulation (MLKEM512, MLKEM768, MLKEM1024) based on the hardness of the Module Learning With Errors (MLWE) problem over polynomial rings. Decapsulation uses implicit rejection—deriving a pseudorandom fallback secret rather than branching or returning an error when a ciphertext is tampered—eliminating adaptive chosen-ciphertext timing side channels.
• NIST FIPS 204 ML-DSA Digital Signatures: Crystal::Pqc::Constant::MLDSAKeyPair implements Module-Lattice-Based Digital Signatures (MLDSA44, MLDSA65, MLDSA87) based on the combined hardness of MLWE and Module Short Integer Solution (MSIS) lattice problems, providing strongly unforgeable digital signatures without elliptic-curve number theory.
• Guarded Memory & Constant-Time Discipline: Post-quantum secret keys (1,632–4,896 bytes) and 32-byte shared secrets are isolated outside Crystal's garbage-collected heap inside libsodium sodium_malloc guarded allocations (mlock + canary + guard page) and locked PROT_READ via sodium_mprotect_readonly. Ephemeral shared secrets are consumed through SharedSecret#consume, which automatically wipes and frees the guarded page on block exit.

Getting Started

Installation & Prerequisites

Ensure host dependencies are installed (libsodium-devel and openssl-devel >= 3.5 on Fedora/RHEL):

# Clone the repository
git clone git@gitlab.com:renich/crystal-crypto-samples.git
cd crystal-crypto-samples

# Install shard dependencies
shards install

Running the Integration Sample

make build
./bin/crystal-crypto-samples

The sample runner executes seven self-contained integration demonstrations:

1. CBOR FIDO (run_cbor_sample): Canonical map key ordering, UInt64 serialization, and canonical IEEE 754 Float16 narrowing (1.5_f64 -> f93e00).
2. ECC Constant (run_ecc_sample): Constant-time Ed25519 detached signatures and mutual X25519 ECDH shared secret agreement (SharedSecret#consume + Sodium.constant_time_equal?) with deterministic sodium_malloc disposal.
3. DBus Native (run_dbus_sample): Recursive SignatureValidator.validate("a{sv}"), BodyCodec a{sv} dictionary marshaling/unmarshaling, SASL EXTERNAL authentication, NEGOTIATE_UNIX_FD negotiation, and full org.freedesktop.DBus.Hello bus registration.
4. TPM2 TSS (run_tpm2_sample): Stateful FIDO2CredentialManager dynamic NV handle persistence, real OpenSSL 3.5 NIST P-256 public key extraction (TPM2_ReadPublic) and ECDSA (r, s) signature verification (FIDO2Credential#verify) with $\mathcal{O}(1)$ SignatureRTracker nonce-reuse verification, plus KDFa XOR and AES-128-CFB parameter encryption roundtrips.
5. PQC Constant (run_pqc_sample): Post-quantum NIST FIPS 203 ML-KEM-768 key encapsulation (1,184-byte public key, 1,088-byte ciphertext, 32-byte shared secret) and NIST FIPS 204 ML-DSA-65 lattice signature generation and verification (1,952-byte public key, 3,309-byte signature).
6. Hybrid Classical-PQC Ceremony (run_hybrid_pqc_sample): Composite X25519 + ML-KEM-768 SHA-256 KDF session key combiner (SHA256("EVALINUX-HYBRID-KEM-V1" || x25519_ss || mlkem768_ss || transcript_cbor)) inside nested SharedSecret#consume blocks and dual Ed25519 + ML-DSA-65 signature generation and verification over canonical integer-keyed CBOR maps.
7. End-to-End D-Bus CTAP2 Authenticator (run_ctap2_dbus_sample): Full D-Bus CTAP2 MakeCredential RPC (ay -> ay) over /org/evalinux/Ctap2Authenticator1 (org.evalinux.Ctap2Authenticator1) serviced by a FIDO2CredentialManager (NIST P-256) and MLDSAKeyPair (ML-DSA-65) responder fiber.

Build System Targets

The repository includes a standard FHS-compliant GNUmakefile:

Documentation

Full architectural blueprints, functional specifications, and operational playbooks are maintained under docs/:

Contributing & Code of Honor

All contributions must adhere to the Universal Code of Honor and Contributing Guidelines.

License

• Software: GNU General Public License v3.0 or later (LICENSE).
• Documentation: GNU Free Documentation License v1.3 or later (LICENSE-DOCS).

Copyleft © 2026 Rénich Bon Ćirić renich@evalinux.com.

Support & Donations

If you find this project useful and wish to support its ongoing development, please consider donating: