CEX - Crypto Express

Enhanced Definition

Crypto Express (CEX) refers to a family of specialized hardware adapters on IBM zSystems mainframes designed to provide high-performance, secure cryptographic services. These PCIe-based cards offload computationally intensive encryption, decryption, hashing, and digital signature operations from the main CPU, enhancing both security and performance for z/OS applications.

Key Characteristics

- Hardware-Based Security: CEX adapters are dedicated physical hardware modules, often certified to FIPS 140-2 Level 4, providing a tamper-resistant environment for cryptographic operations and key storage.
- Cryptographic Offload: They significantly reduce the CPU overhead associated with cryptographic processing, freeing up general-purpose processors for application workloads.
- Multiple Modes of Operation: CEX adapters can operate as Crypto Accelerators (CEX*n*A) for general-purpose cryptographic functions (e.g., SSL/TLS acceleration) or as Crypto Coprocessors (CEX*n*C) for secure key storage and processing within a Hardware Security Module (HSM) context.
- Integrated with ICSF: On z/OS, the CEX hardware is primarily managed and accessed through the Integrated Cryptographic Service Facility (ICSF), which provides the software interface for applications.
- High Throughput: Designed for enterprise-scale workloads, CEX provides high-speed processing for a large volume of cryptographic operations, crucial for secure transactions and data protection.
- Secure Key Management: Crypto Coprocessor modes offer secure generation, storage, and management of cryptographic keys, including master keys and data keys, within the hardware's secure boundary.

Use Cases

- Data Encryption at Rest: Encrypting sensitive data stored in databases (e.g., DB2, IMS), VSAM files, or other datasets using strong cryptographic algorithms.
- SSL/TLS Acceleration: Offloading the cryptographic processing for secure network communications (e.g., HTTPS, SFTP) used by applications like CICS Web Services, z/OS Connect, and TCP/IP, improving response times.
- Digital Signatures and Verification: Generating and verifying digital signatures for data integrity, authentication, and non-repudiation in financial transactions or document processing.
- Secure Key Management: Providing a FIPS-compliant Hardware Security Module (HSM) for the secure generation, storage, and lifecycle management of cryptographic keys used across the enterprise.
- Random Number Generation: Supplying high-quality, hardware-generated random numbers essential for secure cryptographic protocols and key generation.

Related Concepts

CEX adapters are foundational to the cryptographic capabilities of z/OS. They are directly managed by the Integrated Cryptographic Service Facility (ICSF), which acts as the software interface, allowing applications to access the hardware's services. z/OS Security Server (RACF) works in conjunction with ICSF to control access to cryptographic keys and services provided by the CEX. Applications running in environments like CICS, DB2, and IMS leverage CEX via ICSF for secure data handling, SSL/TLS communications, and digital signatures, ensuring data confidentiality and integrity across the mainframe ecosystem.

Best Practices:

ICSF Configuration: Ensure ICSF is properly configured and started with the correct policy and options to fully utilize the CEX adapters and their capabilities.
Key Management Policies: Implement robust key management practices, including regular key rotation, secure backup, and strict access controls for cryptographic keys stored or managed by CEX.
Redundancy and High Availability: Install and configure multiple CEX adapters across different CPCs or LPARs to ensure continuous availability of cryptographic services and fault tolerance.
Performance Monitoring: Regularly monitor CEX utilization, ICSF activity, and application performance to identify potential bottlenecks and optimize cryptographic workloads.
Security Audits: Conduct periodic security audits of cryptographic key usage, access to ICSF services, and CEX configuration to maintain compliance and detect unauthorized activity.