In addition to technologies such as Mimblewimble, zero-knowledge proofs, token mixers, and privacy coins such as Monero and Zcash, "Layer2 solutions such as the Lightning Network can also be abused by criminals." The report notes that the Lightning Network's "two-party multi-signature payment channel does not broadcast all transactions to the blockchain, but only the opening and closing of the channel," adding that it and other Layer2 solutions could cause "problems for law enforcement agencies' investigations."