Bitcoin transactions suffer from a property known as malleability, where certain parts of a transaction inputs script, which can never be committed by a signature (for example, the signatures themselves). Because of this, in certain cases the script can be changed, leaving the transaction still valid, but with a different identifier.
There are numerous avenues for malleability, but presently, an individiual is spamming the network using the low-s
vector. This entails mutating a transactions signature by setting the S value to: -s mod n, an operation which
leaves the signature perfectly valid for that transaction, but results in a different binary representation, and hence
a different hash.
This script attempts listen for mutated transactions on the network, and leverge the malleability of signatures by changing them to it's low-s form. Approximately 95% of recent transactions have used the low-s form, and it has been proposed on several occasions to have nodes automatically fix high-s signatures, as it saves a few bits per signature.
It's use is not encouraged, I just wanted to write a proof of concept.
git clone https://github.com/Bit-Wasp/malleability-fixer.git
cd malleability-fixer
composer install
And to run the application:
bin/app