EXPERIMENTAL FOUR-STATE 2D CODE

QuadQR

Red, green, blue, and white data cells with exactly 2 bits per cell, zero-overhead spectral interleaving, confidence-aware Reed-Solomon ECC, and camera color calibration.

QuadQRRGBWformat v5

Generator

Create QuadQR code

Not generated

Classic keeps every module fully solid. Styles only change rendering, never the encoded data.

SECURE PAYLOAD

Optional authenticated encryption
AES-256-GCM

Standard mode stores the payload normally. Security is opt-in and does not alter QuadQR scanning or Spectrum ECC.

Output

Code

Matrix
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Payload
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Capacity
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Density
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ECC
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Alignment
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RS blocks
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Mask
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Utilization
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Security
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CRC-32
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Image scanner

Scan an exported image or photograph

Secure scanning supported. Password and raw 256-bit-key QuadQR codes are detected automatically. The encrypted payload remains locked until the correct credential is entered in the scan result.

No image scanned yet.

QUADQR FORMAT

Four states, exactly two bits per data cell

Direct 2-bit mapping. Red = 00, green = 01, blue = 10, and white = 11. One byte occupies exactly four data cells.

Spectrum ECC. GF(256) Reed-Solomon first tries normal correction, then uses low-confidence RGBW byte symbols as known erasures when hard decoding is not enough.

Spectral-spatial interleaving. Logical codeword cells are scattered across distant physical modules with a reversible zero-overhead permutation, improving resistance to localized damage without reducing capacity.

Perspective geometry. Three large finder patterns stay fixed. Larger versions keep one 5×5 primary alignment reference and add compact 3×3 secondary markers for stronger geometry and version validation with less capacity overhead.

Adaptive color confidence. RGB swatches plus known structural black/white cells calibrate the palette, while nearest-vs-second-nearest distance gives every sampled data cell a confidence score for ECC.

Secure Payload v1. Optional AES-256-GCM authenticated encryption supports password-derived keys and exact raw 256-bit keys. Encryption sits above Spectrum ECC, so standard symbols keep their existing scan path.

Compact v1. The 21×21 symbol uses a reduced protected header and size-appropriate ECC, giving v1-M 24 payload bytes while retaining CRC-32.

This is a custom experimental symbology. Standard QR scanner apps cannot decode it.