That table can be found in the paper "Stronger Key Derivation via Sequential Memory-Hard Functions"[0] by Colin Percival[1]. This is the paper that introduces explains and introduced scrypt.
The costs are based on what was considered 'modern hardware' in 2009.
The costs are based on what was considered 'modern hardware' in 2009.
[0]: https://www.tarsnap.com/scrypt/scrypt.pdf [1]: https://news.ycombinator.com/user?id=cperciva