Hidden Signal
Local. No uploads.
Same image.
Something inside.
Hide a real message in the pixels. Keep the artwork intact.
1Choose your image
UTF-8 text → Base64 → verified pixels
Choose a PNG created by Hidden Signal. The decoder reads the actual pixels and checks their SHA-256 checksum before displaying any text.
Message region & replacement
Only this rectangle can change. For an unchanged HSG1 file, its region is read automatically. Right and bottom coordinates are exclusive.
Embedded. Reopened. Verified.
0PIXELS TOUCHED
0OUTSIDE REGION
≤ 1BLUE-VALUE CHANGE
Message verified.
Save textChecksum passed. This confirms integrity, not who created the message.
Hidden is not encrypted. Anyone with this decoder can read it. Keep the original PNG: resizing, screenshots, JPEG conversion, or social-platform processing can destroy the message. The region locator is metadata; keep the receipt to recover its coordinates if metadata is stripped.