BusyWork

A Rust library that replaces sleep() with real, varied work. Every call executes a completely different code path — random category, random task, random iteration counts. Breaks static and dynamic analysis pattern matching.

Zero time objects in the library binary. No Duration, no Instant, no SystemTime. Intensity levels control work volume through hardcoded iteration counts, buffer sizes, and call depths.

Usage

use busywork::{busywork, busywork_with, BusyWork, Categories, Intensity};

// Simple — random tasks across all categories
busywork(Intensity::Medium);

// Pick specific categories
busywork_with(Intensity::High, Categories::COMPUTE | Categories::WINAPI);

// Builder for full control
BusyWork::new(Intensity::Ultra)
    .allow(Categories::COMPUTE | Categories::FILESYSTEM)
    .deny(Categories::NETWORK)
    .jitter(true)
    .run();

Drop it in any loop — every iteration looks different:

loop {
    do_real_work();
    busywork(Intensity::Medium); // different execution path every time
}

Intensity Levels

No timers — just work volume:

Level	Tasks/call	Iterations	Buffer size	Call depth
Low	2	50	1 KB	2
Medium	5	500	16 KB	4
High	10	5,000	256 KB	8
Ultra	20	50,000	1 MB	16

Jitter (on by default) randomizes all parameters by ±30%, so two consecutive calls at the same intensity produce different instruction traces.

Categories — 76 Tasks

COMPUTE (14 tasks)

SHA-256 hash chains, MD5 hash chains, prime sieve (Eratosthenes), matrix multiplication, array sorting, deflate compress/decompress, Fibonacci sequence, XOR cipher rounds, Collatz conjecture, string operations, bubble sort, bitwise operations, pi approximation (Leibniz), permutation generation (Heap's algorithm).

MEMORY (10 tasks)

Alloc/touch/free pages, memcpy chains, sort random data, pattern fill & verify, heap fragmentation (many small allocs), ring buffer simulation, repeated binary search, buffer reversal, buffer interleaving, scatter/gather access patterns.

FILESYSTEM (12 tasks)

Enumerate System32, temp dir, Program Files, fonts, drivers, prefetch, logs, user profile. Stat system files & DLLs. Read hosts, services, win.ini, system.ini. All read-only — no files created or modified.

REGISTRY (10 tasks)

Read installed software, system info (ProductName, CurrentBuild), services, timezone, environment variables, network config (TCP/IP parameters), CPU hardware info, font list, startup programs (Run keys), file associations (HKCR). All KEY_READ — no writes.

WINAPI (16 tasks)

Enumerate windows (EnumWindows + GetWindowTextW), enumerate processes (ToolHelp32 snapshot), system info (GetSystemInfo, GlobalMemoryStatusEx), clipboard read, system metrics (10 indices), foreground window, cursor position, desktop window, logical drives + drive types, volume info, disk free space, FindFirstFile/FindNextFile, module handles (12 DLLs), VirtualQuery memory walk, system/Windows directories, process/thread IDs.

NETWORK (7 tasks)

DNS lookups (24 hosts), HTTP GET (11 endpoints), NTP queries (7 servers), HTTP HEAD requests, TCP connect probes (10 host:port targets), DNS with varied ports, HTTP POST/PUT to echo endpoints. Socket timeouts via raw setsockopt — no Duration type.

CRYPTO (7 tasks)

BCryptGenRandom (system CSPRNG), BCrypt SHA-256 hashing, BCrypt SHA-512, BCrypt MD5, BCrypt SHA-1, AES-256 symmetric encrypt, RNG algorithm providers (RNG, FIPS186DSARNG, DUALECRNG).

Benchmarks

Measured on Windows 11, debug build, 5 runs each:

By Intensity (all categories)

Level	Min	Avg	Max
Low	0.10 ms	0.19 ms	0.33 ms
Medium	3.26 ms	941 ms	3,064 ms
High	133 ms	1,855 ms	6,322 ms
Ultra	4,439 ms	58,450 ms	176,147 ms

The wide min/max spread is intentional — each call picks different tasks with different costs.

By Category (Medium intensity)

Category	Min	Avg	Max
COMPUTE	14.69 ms	499 ms	1,256 ms
MEMORY	14.93 ms	123 ms	242 ms
FILESYSTEM	0.81 ms	21.2 ms	48.0 ms
REGISTRY	0.93 ms	4.64 ms	17.8 ms
WINAPI	0.28 ms	5.01 ms	19.1 ms
NETWORK	1,188 ms	3,350 ms	6,318 ms
CRYPTO	5.47 ms	8.77 ms	12.8 ms

Feature Flags

Each category is a cargo feature, all on by default:

[dependencies]
busywork = "0.1"

# Or cherry-pick:
busywork = { version = "0.1", default-features = false, features = ["cat-compute", "cat-memory"] }

Feature	Dependencies	Description
cat-compute	sha2, md-5, flate2	Pure CPU work
cat-memory	—	Allocation patterns
cat-filesystem	—	Read-only filesystem I/O
cat-registry	windows	Windows Registry reads
cat-winapi	windows	Win32 API calls
cat-network	—	DNS, HTTP, NTP
cat-crypto	windows	Windows CNG (BCrypt) crypto

Design

• Every call is unique — random category selection, random task within category, random iteration counts
• No deterministic signature — even at the same intensity, call A and call B look nothing alike
• Task registry rebuilt per call — no stable global pointer, prevents devirtualization
• Function pointers, not trait objects — diverse call targets, no vtable pattern
• black_box on all results — prevents dead-code elimination
• Windows-only — full Win32 API access, no cross-platform abstraction layer

Stats

76 tasks across 7 categories
2,688 lines of Rust
0 time objects in the library binary