The Adumbra library Adumbra is a light-weight Java library that uses steganography to hide data in bitmaps using a secret key. Supported input formats include PNG, JPEG, TIFF, BMP. Output formats are PNG and TIFF only, because other formats are lossy and therefore more difficult to support. Adumbra requires a bitmap with about 500 pixels for every byte of the secret message, so a bitmap of 500x700 pixels could contain a secret message of up to about 700 bytes. The maximum size of the secret mess...