> For the complete documentation index, see [llms.txt](https://cryptic-documentation.gitbook.io/cryptic-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cryptic-documentation.gitbook.io/cryptic-documentation/technology/2.-technology-overview/2.2-quantum-resistant-security-stack.md).

# 2.2 Quantum‑Resistant Security Stack

Cryptic implements modern post-quantum cryptographic primitives designed to protect communication, identity, and key exchange against long-term quantum risk.

The security stack supports Cryptic’s full product architecture across **SDK, Desktop, and Mobile**, enabling encrypted communication, secure invite flows, message verification, wallet-related authentication, and future developer integrations.

#### **ML-DSA / CRYSTALS-Dilithium (Digital Signatures)**

| Variant       | NIST Level | Signature Size | Public Key Size | Private Key Size |
| ------------- | ---------: | -------------: | --------------: | ---------------: |
| Dilithium II  |    Level 2 |         2.4 KB |          1.3 KB |           2.5 KB |
| Dilithium III |    Level 3 |         3.2 KB |          1.9 KB |           4.0 KB |
| Dilithium V   |    Level 5 |         4.2 KB |          2.5 KB |           4.8 KB |

ML-DSA / Dilithium is used for post-quantum digital signatures, helping verify identity, message integrity, invite handshakes, and signed protocol data.

#### **ML-KEM / CRYSTALS-Kyber (Key Encapsulation)**

| Variant     | Security Level | Ciphertext Size | Public Key Size | Private Key Size | Shared Secret Size |
| ----------- | -------------: | --------------: | --------------: | ---------------: | -----------------: |
| ML-KEM-512  |        128-bit |       800 bytes |       800 bytes |      1,632 bytes |           32 bytes |
| ML-KEM-768  |        192-bit |     1,184 bytes |     1,184 bytes |      2,400 bytes |           32 bytes |
| ML-KEM-1024 |        256-bit |     1,568 bytes |     1,568 bytes |      3,168 bytes |           32 bytes |

ML-KEM / Kyber is used for post-quantum key encapsulation and shared secret establishment, allowing Cryptic clients to create encrypted communication channels.

#### **Security Principles**

* **Misuse-Resistant APIs**\
  High-level cryptographic interfaces reduce developer error and unsafe composition.
* **Constant-Time Operations**\
  Cryptographic implementations are designed to mitigate timing-based side-channel attacks.
* **Post-Quantum Key Exchange**\
  ML-KEM supports shared secret establishment for encrypted communication flows.
* **Post-Quantum Signature Verification**\
  ML-DSA supports stronger verification for signed protocol data and invite handshakes.
* **Secure Key Storage**\
  Private keys are protected using platform-native secure storage and hardware-backed protections where supported, including Secure Enclave, Android Keystore, StrongBox, and other secure execution environments where applicable.
* **Hybrid Security Model**\
  Cryptic can combine post-quantum primitives with classical cryptographic tools where appropriate, supporting practical security today while preparing for long-term quantum risk.

> *Cryptic’s security stack is designed to make post-quantum protection usable across real products: SDK for developers, Desktop for power users, and Mobile for everyday communication and payments.*