explain multisig complexities and how aggregate sigs can help
= Signing
+All of the aforementioned mechanisms require that there is a M-of-N
+multisignature wallet guarding each Deposit on Bitcoin.
+
+Bitcoin's consensus rules restrict script size to 520 bytes (10,000 bytes for Segwit
+outputs), limiting the size of multisignature scripts. Future proposals such as
+link:https://github.com/bitcoin/bips/blob/master/bip-0114.mediawiki[MAST] would
+allow implementing larger multisigs, however the activation of new features on
+Bitcoin has historically been a procedure with unclear timelines.
+
+Finally, large multisignature wallets in Ethereum and Bitcoin both have
+increasing verification costs as the number of participants increases. Building
+multisgs on Ethereum is link:https://www.coindesk.com/30-million-ether-reported-stolen-parity-wallet-breach[particularly] link:https://www.coindesk.com/ico-funds-among-millions-frozen-parity-wallets[hard]. By
+utilizing link:https://crypto.stanford.edu/~dabo/pubs/papers/aggreg.pdf[provably
+secure aggregate signatures], we can remove all of the above complexities and
+replace them by a simple single signature verification.
+
+Intuitively, an aggregate public key is generated from all multisignature
+participants who communicate via an out of band protocol, a process also known
+as Distributed Key Generation (DKG). Each participant signs the intended message
+with their private key and contributes a "share" of the final aggregate
+signature. Assuming ECDSA, the aggregate signature can then be verified against the aggregate public key
+with an OP_CHECKSIGVERIFY on Bitcoin, or an ECRECOVER operation on Ethereum.
+This process is simple and inexpensive, and avoids the path of implementing
+complex multisignature verification logic which can be upgraded for different
+M-of-N configurations. If another configuration is required, the script or the
+smart contract only need to be configured to use a new aggregate public key
+after re-executing the DKG.
+
ifndef::tbtc[toc::[]]
== Threshold ECDSA
@@ -10,5 +38,5 @@ ifndef::tbtc[toc::[]]
== Future Signature Schemes
-* Schnorr
+* Schnorr: MuSig
* BLS
\ No newline at end of file
