fastcrypto is used at run time in 5 crates (of which 1 optionally).

Depender (with downloads and own rev deps) fastcrypto version
1.0K af-keys ^0.1.9
1.7K af-iperps optional ^0.1
390 1 fastcrypto-zkp ^0.1.5
fastcrypto-tbls ^0.1.8
obc-salt ^0.1.8