SM4 Cipher Engine

The SM4 IP core implements a custom hardware accelerator for the SM4 symmetric block cipher, specified in Chinese national standard GB/T 32907-2016, and ISO/IEC 18033-3:2010/Amd 1:2021.

Designed for easy integration, the core, internally expanding the 128-bit key, is capable of both encryption and decryption and features a simple handshake input and output data interface. To further simplify integration, CAST separately offers interface bridges to AMBA™ AXI4-Stream and integration with DMA engines to facilitate operation as a memory-mapped peripheral.

The core is available in a Fast version (SM4-F), offering a throughput of 4 bits/cycle, while a High-throughput version (SM4-X) operating at 128 bits/cycle is optionally available. Variants supporting different cipher modes provisioned by NIST SP 800-38 recommendations (i.e. ECB, CBC, CFB, OFB, CTR, GCM, CCM, XTS) are optionally available for both versions.

The SM4 is rigorously verified, LINT-clean and scan-ready. It is straightforward to implement on any technology as it is a strictly synchronous design using only rising clock edges, an asynchronous reset line and requires no special timing constraints.

Security Mechanism Support

• Encryption/Decryption per:
  • Chinese national standard GB/T 32907-2016, and
  • ISO/IEC 18033-3:2010/Amd 1:2021

Versions and Variants

• Versions:
  • SM4-F: 4-bits/cycle
  • SM4-X: 128-bits/cycle
• Variants (different cipher modes):
  • ECB, CBC, CFB, OFB, CTR, GCM, CCM, XTS

Fast & Compact

• 8 Gbps with less than 10k eq. gates on modern technologies (SM4-F)

Easy Integration and Trouble-Free Technology Mapping

• Simple handshake interface
• Bridges to AXI4 Stream and DMA integration separately available
• Fully synchronous, single-clock domain, re-usable design
• No false or multicycle timing paths, scan-ready, LINT-clean

• The SM4 crypto engine core is easily portable to ASIC and FPGA. It supports a wide range of applications on various technologies. The unique architecture enables a high level of flexibility.

• The SM4 IP core is a versatile symmetric block cipher engine that can be deployed across diverse security-critical domains, which require compact solutions with high-throughput. Application areas include: IoT devices, Wireless Networking (WAPI), Secure communications (encrypted messaging, VoIP, VPNs), Trusted Platform Modules (TPMs), Mobile baseband processors, Data storage security (flash memory, SSDs, and encrypted storage solutions), Digital Payment Systems (e-payment terminals, smart cards, mobile payment apps).

• RTL source code (VHDL or Verilog) or targeted FPGA netlist
• HDL testbench
• C model and test-vector generator
• Simulation and synthesis scripts
• Documentation