tECDSA 3-of-3 multi-signer implementation

[Shadowfiend]

Also involves:

• Investigating Binance implementation: https://github.com/binance-chain/tss-lib

High-level estimate: XL
Breakdown: @Shadowfiend @nkuba

• Read and understand Fast tECDSA paper - Read and understand Fast tECDSA paper keep-ecdsa#91
• Investigate Binance's tss-lib implementation - Investigate Binance's tss-lib implementation keep-ecdsa#92
• Figure out structural dependencies between Binance/keep-core - Figure out structural dependencies between Binance/keep-core keep-ecdsa#93
• Implement protocol executor - Implement tECDSA protocol executor keep-ecdsa#94
• Key Generation stage execution - Key Generation stage execution keep-ecdsa#95
• Signing stage execution - Signing stage execution keep-ecdsa#96
• Integrate protocol executor with ECDSA keep client - Integrate protocol executor with ECDSA keep client keep-ecdsa#97
• Upgrade libp2p - Upgrade libp2p keep-ecdsa#98
• Implement formation/DKG against libp2p - Implement formation/DKG against libp2p keep-ecdsa#99
• Implement signing against libp2p - Implement signing against libp2p keep-ecdsa#100
• Implement group teardown - Implement group teardown  keep-ecdsa#101
• Implement signer choice for group - Implement signer choice for group keep-ecdsa#102
• Network messages transport - Secure network messages transport keep-ecdsa#103
• Timeouts handling - Timeouts handling keep-ecdsa#104
• Implement smoke test - Implement smoke test keep-ecdsa#105

May not block audit:

• Implement transaction submission to BTC: 4pt
  Should we be doing this in the dApp only? tbtc-maintainer? Signing group?
• Exploratory testing: 8
  Try to break as much as possible.

Audit total: 74pt
Total: 86pt

[Shadowfiend]

We done.