Breaks an ecdsa implementation that uses privKey xor message as nonce. Recovering the full private key requires 512 signatures. In other words, every signature leaks 0.5 bit. It is probable that the attack can be refined such that each signature leaks 1 bit. An detailed explanation of the attack can be found in the explanation.pdf.

main.go is the implementation of an attack specifically against a vulnerable version of github.com/obscuren/secp256k1-go. The obvious fix is to use the operating system's PRNG to generate the nonce just like the original project by haltingstate.