Why StegaStamp can only encode 56bits (7 characters) with ECC?

[linzissu]

Dear tancik:

I got the following error when running encode_image.py:

Error: Can only encode 56 bits (7 characters) with ECC.

I'm confused about why it can only encode 56 bits (7 characters) with ECC.

Thanks in advance! 😄

[tancik]

The total message budget is 100 bits but some of the bits need to be used for error correction. We use BCH codes which you can learn more about here - https://en.wikipedia.org/wiki/BCH_code