png_data/README.md

png_data -- Data as images

png_data -- Data to PNG

png_data transforms a file as a png image.

Encoding

png_data -l rgb8 -e file.pdf -o output.png -c "(.pdf) documentation" Where:

• rgb8 is the RGB layout with 8 bits per pixel
• file.pdf is the file to store in the resulting image
• output.png the resulting png image

Available layouts

• rgb[8|16] RGB with 8 or 16 bits per channel
• rgba[8|16] RGBA with 8 or 16 bits per channel (densest layout)
• g[1|2|4|8|16] Grayscale with 1-16 bits per channel
• ga[1|2|4|8|16] Grayscale Alpha with 1-16 bits per channel

Decoding

png_data -d output.png -o original.pdf Where:

• output.png the encoded png image
• original.pdf the resulting decoded file

Getting header information

png_data -z output.png

• output.png a png_data encoded image This will display the header of the encoded file, as well as the comment.

png_embed -- Embed files into mostly innocent PNG

png_embed encodes a file into an existing png image making it possible to recover that file by passing the image around.

Current algorithm:

• lo Embeds data in the colors channels lowest bits.

See examples/test.sh for usage.

Encoding an image

png_embed -l lo2 -e embed.tar original.png -o output.png -c "(.tar) archive" Where:

• lo2 is the Lo algorithm using the 2 lowest bits
• embed.tar the file to embed into the final image
• original.png the original PNG file
• output.png the resulting PNG file
• "(.tar) archive" an optional comment

Decoding an image

png_embed -l lo2 -d image.png -o embed.tar Where:

• lo2 is the Lo algorithm using the 2 lowest bits
• image.png the PNG containing an embed
• embed.tar the extracted embedded file

Getting header information

png_embed -l lo2 -z output.png

• lo2 is the Lo algorithm using the 2 lowest bits
• output.png a png_embed encoded image This will display the header of the encoded file, as well as the comment.

License

png_data is licensed under the GNU AGPL version 3 or later. See LICENSE.md for more information. License for third-party dependencies can be accessed via cargo license