 Privacy amplification was implemented via GF[2n] Universal Hash.Entropy estimation was based on Rényi entropy, and implemented by BBBSS 92, Slutsky, Myers / Pearson, and Shor / Preskill protocols.Error correction was implemented by a BBN variant of the Cascade protocol, or the BBN Niagara protocol which provided efficient, one-pass operation near the Shannon limit via forward error correction based on low-density parity-check codes (LDPC).