SHA-256

Cryptographic Hash & SIMD Stress Testing

Overview

The SHA-256 module implements hardware-accelerated cryptographic hashing using Intel SHA-NI (SHA New Instructions) extensions. This module combines intensive SIMD operations, parallel state processing, and complex bit manipulations to create maximum stress on your CPU's vector processing units and cryptographic acceleration hardware.

Implementation Details

SHA-NI Accelerated Hashing

Utilizes Intel's dedicated SHA-256 instructions for hardware-accelerated cryptographic operations. Four parallel hash states process different data streams simultaneously, maximizing throughput and SIMD unit utilization.

; Parallel SHA rounds on multiple states sha256rnds2 xmm0, xmm1 ; State 1 sha256rnds2 xmm2, xmm3 ; State 2 sha256msg1 xmm6, xmm7 ; Message schedule

Message Schedule Engine

Advanced message scheduling using SHA256MSG1 and SHA256MSG2 instructions combined with complex data shuffling patterns. Multiple data streams are processed with byte swapping and realignment operations for maximum computational density.

; Message schedule with data transformation pshufb xmm4, xmm14 ; Byte swap sha256msg2 xmm6, xmm4 ; Schedule computation palignr xmm0, xmm1, 8 ; Data alignment

Hardware Stress Targets

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SHA-NI Execution Units

Dedicated cryptographic hardware acceleration units are saturated with continuous SHA-256 round operations and message scheduling.

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SIMD Vector Units

128-bit XMM registers and vector operations stress SSE/AVX execution pipelines with parallel data processing.

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Data Transformation

Intensive byte shuffling, bit rotation, and data alignment operations stress the CPU's shuffle and permutation units.

Memory Subsystem

Multiple data streams with 64-byte aligned access patterns create sustained memory bandwidth utilization.

Performance Characteristics

Computational Intensity

Parallel States
64 Rounds per Block
128KB Test Data Size
100% SIMD Utilization

Advanced Features

Hardware Detection

Automatic CPUID-based detection of SHA-NI support with graceful fallback for unsupported processors.

Parallel Processing

Four independent hash states process different data streams simultaneously for maximum throughput.

Data Stream Rotation

Dynamic data stream switching prevents cache optimization and maintains computational complexity.

Mixed Operations

Combination of cryptographic, integer, and floating-point operations for comprehensive CPU stress.

Technical Implementation

SHA-NI Optimization Features:

  • Hardware-accelerated SHA256RNDS2 instruction usage
  • Optimized message scheduling with SHA256MSG1/MSG2
  • Parallel state processing across multiple XMM registers
  • 128-byte aligned data structures for optimal memory access
  • Position-independent code (PIC) for library compatibility

SIMD Optimizations:

  • PSHUFB for efficient byte-order conversion
  • PALIGNR for data stream alignment operations
  • PSHUFD for 32-bit element shuffling
  • PBLENDW for conditional data merging
  • Minimal scalar operations to maintain vector focus

Stress Testing Enhancements:

  • Configurable iteration count (default: 1 million)
  • Multiple test data patterns to prevent optimization
  • Integer and floating-point operations between rounds
  • Dynamic pointer manipulation for cache pressure
  • Continuous execution without early termination
⚠️ Hardware Requirements

This module requires Intel SHA-NI support (Intel processors from Goldmont/Skylake generation onwards, or AMD Zen architecture). The module includes runtime detection and will report compatibility. Extended execution will saturate cryptographic units and may cause thermal throttling.

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