nickfarrow

Private Collaborative Custody with FROST

With multiparty computation multisignatures like FROST [0], it is possible to build a collaborative custodian service that is extremely private for users.

Today's collaborative custodians can see your entire wallet history even if you never require them to help sign a transaction, and they have full liberty to censor any signature requests they deem inappropriate or are coerced into censoring.

With FROST, a private collaborative custodian can hold a key to a multisig while remaining unaware of the public key (and wallet) which they help control. By hiding this public key, we solve the issue of existing collaborative custodians who learn of all wallet transactions even if you never use them.

Further, in the scenario that we do call upon a private collaborative custodian to help sign a transaction, this transaction could be signed blindly. Being blind to the transaction request itself and unknowing of past onchain behavior, these custodians have no practical in

nadavrot

High-Performance Matrix Multiplication

This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).

Intro

Matrix multiplication is a mathematical operation that defines the product of

hellman

#include <iostream>
#include <stdlib.h>
using namespace std;

#define REP(i,x) for(int i = 0; i < (int)x; i++)
#define M 8

int N;
string s[1000];
long q[M], p[M], hs[M][1000], hr[M][1000];