Just me developing a pure Python from-scratch zero-dependency implementation of Bitcoin for educational purposes, including all of the under the hood crypto primitives such as SHA-256 and elliptic curves over finite fields math.

SHA-256 My pure Python SHA-256 implementation closely following the NIST FIPS 180-4 spec, in cryptos/sha256.py. Since this is a from scratch pure Python implementation it is slow and obviously not to be used anywhere except for educational purposes.