Modern financial, banking, fintech, healthcare, and enterprise applications increasingly depend on APIs to exchange sensitive information between clients and backend services. Traditional HTTPS/TLS provides strong transport-layer security, but applications handling highly sensitive transactions may require an additional cryptographic protection layer at the application level.
One approach is to combine Elliptic Curve Cryptography (ECC) with modern symmetric encryption to establish secure communication between an API client and server.
A practical architecture is to use:
ECDH P-256 for secure key agreement
HKDF-SHA256 for deriving session encryption keys
AES-256-GCM for authenticated encryption of API payloads
TLS 1.3 for transport security
ECDSA for cryptographic authentication and request signing
mTLS for strong client/server identity
Redis or a distributed session store for scalable session management
