Crypto Coprocessor

Crypto Coprocessor

A crypto coprocessorcrypto coprocessorHardwareDedicated crypto hardware on chip.Click to view → (also called a cryptographic accelerator) is a dedicated hardware block on a smart card chip that performs computationally intensive cryptographic operations — RSA, ECC, AES, 3DES, and SHA — at speeds far exceeding what the card's main CPU could achieve in software. It is a critical component of every Secure Element, enabling real-time cryptographic operations within the power and time constraints of a smart card transaction.

Why Hardware Acceleration Is Necessary

Smart card CPUs are typically 8-bit, 16-bit, or 32-bit RISC cores running at 10-50 MHz — far less powerful than the processors in phones or laptops. Without dedicated hardware, a 2048-bit RSARSACryptographyPublic-key algorithm for smart card signatures and key exchange.Click to view → signature would take 30+ seconds on an 8-bit CPU, making it impractical for payment transactions that must complete within 500 ms.

Architecture

A modern smart card crypto coprocessor contains multiple functional units:

The coprocessor is connected to the main CPU via an internal bus. The CPU loads key material and plaintext into coprocessor registers, triggers the operation, and reads the result — without the key ever leaving the hardware boundary.

DPA-Resistant Design

Because the crypto coprocessor is the primary target for SPA/DPA attacks, its circuit design incorporates specific countermeasures: dual-rail logic that draws constant power regardless of data values, random execution delays, blinded intermediate computations, and hardware masking. These protections are evaluated during Common Criteria certification and are scored using the JIL vulnerability assessment methodology.

Post-Quantum Readiness

Leading chip manufacturers are developing crypto coprocessors with support for post-quantum algorithms (CRYSTALS-Dilithium, CRYSTALS-Kyber) to future-proof smart card platforms against quantum computing threats. These algorithms require significantly more memory and computation, driving the shift to 32-bit cores with larger flash memory and higher-throughput coprocessor designs.