Steganography Detector
Statistical steganalysis using four algorithms — chi-square, RS analysis, sample pairs, primary sets. StegExpose-equivalent. Payload size estimate. Method fingerprint. WAV audio support. No upload.
🔍 You can't see what's hidden by looking at it.
Statistical analysis can. Four mathematical tests — chi-square, RS analysis, sample pairs, primary sets — detect the invisible fingerprint steganography leaves behind.
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Loads a 300×300 gradient PNG for analysis — no upload needed
Aperi'Solve and most online steganalysis tools upload your files to their servers. This tool runs entirely in your browser via OffscreenCanvas, Web Crypto API, and WebWorkers. For forensic evidence with chain-of-custody requirements — this is the only browser option.
How to Detect Steganography in an Image (5 steps)
- Upload a suspicious image (PNG, BMP, JPEG) or WAV audio file
- Four statistical algorithms run automatically — chi-square, RS analysis, sample pairs, primary sets
- Detection score above 0.7 = steganography detected, 0.4–0.7 = suspicious, below 0.4 = likely clean
- See payload estimate (approximately how many bytes are hidden) and likely method used
- Download the forensic report for investigation documentation
Four Statistical Detection Algorithms — Comparison
| Algorithm | Best For | Payload Estimate? | Reliability |
|---|---|---|---|
| Chi-Square Attack | Sequential LSB at >10% density | No — probability only | High for sequential LSB |
| RS Analysis | Any LSB — most reliable | Yes — bpp estimate | Very high — works for adaptive LSB |
| Sample Pairs | Randomized LSB at >2% | Yes — independent estimate | High across LSB variants |
| Primary Sets | Low embedding rates (<5%) | No — probability only | Medium — sensitive at low rates |
| Fusion (all 4) | Any LSB method — all rates | Yes — combined estimate | Highest — StegExpose methodology |
Frequently Asked Questions
What is the difference between this tool and the Steganography Analyzer?
The Steganography Analyzer focuses on extraction — 'What is hidden and can I extract it?' The Steganography Detector focuses on detection — 'Is something hidden, how much, and what method?' The detector provides probability scores, payload size estimates, and method fingerprints but does not extract the payload. Use the detector first to determine whether a file is suspicious, then use the appropriate extraction tool.
How accurate is the detection score?
The detection score fuses four statistical tests using the StegExpose methodology, validated on 15,200 images with 5,200 stego files at 2.5–25.3% embedding rates. Score above 0.7 indicates high probability of steganography. False positive rate is approximately 5% at this threshold. Adaptive steganography methods (HILL, WOW, UNIWARD) and very low embedding rates (<2%) may evade detection.
Does this tool upload my files?
No. All analysis runs entirely in your browser using OffscreenCanvas, Web Crypto API, and WebWorkers. No network requests are made during analysis. For forensic investigations where chain-of-custody matters — your file never leaves your device.
How does the payload size estimate work?
RS Analysis is the most reliable method for payload estimation. It derives a bits-per-pixel (bpp) embedding rate by solving a quadratic equation derived from how pixel 'regularity' and 'singularity' change when LSBs are flipped. This bpp estimate is multiplied by total pixels to estimate bytes. For lossless formats (PNG, BMP) accuracy is typically ±20%. JPEG estimates are less reliable due to lossy compression affecting LSB statistics.
What is method fingerprinting?
After running all four statistical tests, the tool analyses the pattern of which tests triggered and which channels show anomalies. Sequential LSB shows high chi-square AND sample pairs on the same channel. Adaptive LSB triggers RS analysis but not chi-square (non-sequential pixel selection). JPEG DCT methods show different coefficient distribution anomalies. The fingerprint suggests which steganography tool likely created the file.
Can this tool detect steganography in WAV audio?
Yes. WAV audio analysis applies chi-square and sample pairs to 16-bit PCM samples, measures LSB frequency deviation, and checks for structured patterns in high-frequency bands. The same statistical principles apply: LSB embedding in audio samples creates detectable irregularities in the sample value distribution.
Why is JPEG analysis less reliable?
JPEG's lossy compression quantizes pixel values, destroying the precise LSB statistics that chi-square and RS analysis rely on. Steganography in JPEG typically works in the DCT coefficient domain (JSteg, F5, Steghide) rather than the spatial LSB domain. The detector runs DCT coefficient analysis for JPEG files, but this is less mature than the spatial LSB tests. PNG and BMP analysis is significantly more reliable.
What should I do if the fusion score is in the Suspicious range (0.4–0.7)?
A suspicious score means statistical anomalies are present but below the high-confidence detection threshold. This can mean: a small payload at low embedding rate, an adaptive method that partially evades detection, or naturally unusual image statistics. Recommended actions: examine the bit plane viewer for structured noise, check the EOF for trailing data, and try extraction tools (LSB extractor, steganography extractor) to see if any payload is recoverable.
How does batch analysis work?
Drop up to 50 files (images or WAV). Analysis runs in parallel using a WebWorker pool sized to your CPU cores. Results are sorted by detection score descending — highest-risk files appear first. Export a CSV report compatible with SIEM tools (Splunk, QRadar, Microsoft Sentinel) for security operations workflows.
Is this a StegExpose replacement?
This tool implements the same four statistical algorithms (chi-square, RS analysis, sample pairs, primary sets) and fusion methodology as StegExpose, but runs in a browser with no installation required. StegExpose is a Java CLI that requires a JRE and command-line access. This tool provides an equivalent browser-based analysis with the addition of visual evidence, method fingerprinting, and forensic reporting.
What steganography methods can this tool detect?
The four statistical tests reliably detect LSB steganography — the most common method. This includes tools like OpenStego, SilentEye, Steghide (spatial mode), most online steganography tools, and all tools on this platform. The tool has limited ability to detect adaptive methods (HILL, WOW, UNIWARD) that preserve statistical properties, and deep learning-based methods. For those, GPU-based detectors like Aletheia would be needed.