# f4jumble An implementation of the F4Jumble algorithm, an unkeyed variable-width permutation. F4Jumble is used by Zcash Unified Addresses and Unified Viewing Keys to prevent certain kinds of malleation attacks, and is specified by [ZIP 316](https://zips.z.cash/zip-0316). ## License Licensed under either of * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) at your option. ### Contribution Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.