AES-256 is the gold standard for symmetric encryption, used by governments, military, and financial institutions worldwide. Unlike public-key systems (RSA, ECDSA) which are fully broken by quantum computers, AES-256 remains secure in the post-quantum era — though with reduced effective security.
Quantum impact on AES: Grover's algorithm gives quantum computers a quadratic speedup against symmetric ciphers. This effectively halves the key length: AES-256 drops to 128-bit security post-quantum. AES-128 would drop to 64-bit security (breakable). This is why AES-256 is the minimum for quantum-safe symmetric encryption.
BMIC's AES-256-PQC: BMIC implements AES-256 with additional quantum-hardened key derivation functions (AES-256-PQC). All data at rest and in transit within the BMIC ecosystem — wallet storage, transaction payloads, staking contract state — is encrypted with AES-256-PQC. Combined with CRYSTALS-Kyber for key exchange, this provides full-stack quantum resistance.