Bletchley Park ‘Rectangling’ and LDPC codes

For now, this is my final post arising from the General Report on Tunny. I looked at the connection between:

  • ‘Rectangling’, part of the cryptanalysis performed by the Bletchley Park codebreakers on the Lorenz cipher, and
  • Belief Propagation decoding of LDPC error-correcting codes.

See the write-up and code repo for details.