papers/hanzo-network-architecture/sections/04-post-quantum-cryptography.tex

\section{Post-Quantum Cryptography}


Hanzo implements production-ready PQC compliant with NIST FIPS 203/204 standards, addressing the threat of quantum computers to current cryptographic systems.

\subsection{Algorithm Selection}

\subsubsection{ML-KEM (FIPS 203)}

Module-Lattice Key Encapsulation Mechanism:

\begin{itemize}
\item \textbf{ML-KEM-512}: 128-bit security, lightweight IoT
\item \textbf{ML-KEM-768}: 192-bit security, \textbf{default}
\item \textbf{ML-KEM-1024}: 256-bit security, maximum protection
\end{itemize}

Key sizes (ML-KEM-768):
\begin{itemize}
\item Encapsulation key: 1184 bytes
\item Decapsulation key: 2400 bytes
\item Ciphertext: 1088 bytes
\item Shared secret: 32 bytes
\end{itemize}

\subsubsection{ML-DSA (FIPS 204)}

Module-Lattice Digital Signature Algorithm:

\begin{itemize}
\item \textbf{ML-DSA-44}: 128-bit security, fast verification
\item \textbf{ML-DSA-65}: 192-bit security, \textbf{default}
\item \textbf{ML-DSA-87}: 256-bit security, maximum protection
\end{itemize}

Signature sizes (ML-DSA-65):
\begin{itemize}
\item Verification key: 1952 bytes
\item Signing key: 4032 bytes
\item Signature: 3309 bytes (deterministic)
\end{itemize}

\subsection{Privacy Tiers}

Hanzo implements a five-tier privacy model with automatic algorithm selection:

\begin{table}[h]
\centering
\small
\begin{tabular}{|c|l|c|c|}
\hline
\textbf{Tier} & \textbf{Environment} & \textbf{ML-KEM} & \textbf{ML-DSA} \\
\hline
0 & Open Data & 768 & 65 \\
1 & At-Rest Encryption & 768 & 65 \\
2 & CPU TEE & 768 & 65 \\
3 & GPU CC (H100) & 1024 & 87 \\
4 & GPU TEE-I/O & 1024 & 87 \\
\hline
\end{tabular}
\caption{Privacy tier algorithm selection}
\label{tab:privacy_tiers}
\end{table}

Tier 3/4 support NVIDIA H100 Confidential Computing and Blackwell TEE-I/O with:
\begin{itemize}
\item Encrypted DMA transfers
\item NVLink security
\item Attestation-based key release
\item Hardware-backed enclave protection
\end{itemize}

\subsection{Hybrid Mode}

Defense-in-depth via combined PQC + classical crypto:

\begin{equation}
K_{\text{shared}} = \text{KDF}(K_{\text{ML-KEM}} \parallel K_{\text{X25519}})
\end{equation}

Using HKDF (SP 800-56C compliant):

\begin{equation}
\text{KDF}(IKM, salt, info, L) = \text{HKDF-Expand}(\text{HKDF-Extract}(salt, IKM), info, L)
\end{equation}

This protects against both classical and quantum attacks, with security level $\max(\text{ML-KEM}, \text{X25519})$.

\subsection{Key Broker Service (KBS)}

Attestation-based key release (\texttt{hanzo-kbs}):

\begin{algorithm}
\caption{PQC-Enhanced Key Release}
\begin{algorithmic}[1]
\REQUIRE TEE attestation report, privacy tier
\ENSURE Wrapped DEK (Data Encryption Key)
\STATE Verify TEE attestation signature
\STATE Check attestation measurements against policy
\STATE Select KEK (Key Encryption Key) based on tier
\IF{tier $\geq$ 3}
    \STATE Use ML-KEM-1024 with GPU CC vault
\ELSE
    \STATE Use ML-KEM-768 with standard vault
\ENDIF
\STATE Generate ephemeral keypair $(pk, sk)$
\STATE Encapsulate: $(ct, ss) \leftarrow$ ML-KEM.Encap$(pk)$
\STATE Derive KEK $\leftarrow$ HKDF$(ss)$
\STATE Wrap DEK with ChaCha20Poly1305-KEK
\RETURN $(ct, \text{wrapped\_DEK})$
\end{algorithmic}
\end{algorithm}

\subsection{Performance Benchmarks}

Measured on Apple M2 Max (12-core CPU):

\begin{table}[h]
\centering
\small
\begin{tabular}{|l|c|c|}
\hline
\textbf{Operation} & \textbf{ML-KEM-768} & \textbf{ML-DSA-65} \\
\hline
Keygen & 47 $\mu$s & 98 $\mu$s \\
Encap/Sign & 58 $\mu$s & 241 $\mu$s \\
Decap/Verify & 71 $\mu$s & 117 $\mu$s \\
\hline
\end{tabular}
\caption{PQC operation latencies}
\label{tab:pqc_perf}
\end{table}

These timings enable real-time encryption/signing for high-throughput workloads.