A tool to perform common attacks (e.g. length extension) and operations relating to the SHA256 hashing algorithm
Simply calculate the SHA256 digest of some input data and output it in the desired format:
Perform a length extension attack given the hash of some unknown data, the length of the data, and some additional data to append.
Given H(m) and some data d, calculate H(m|p|d) where p is the original SHA256 padding added to m.
The hash of the unknown data + the original sha256 padding + the new message was successfully calculated (as it matches the expected value at the bottom).