InChIKey

https://doi.org/10.1351/goldbook.11455

A fixed length (character) condensed digital representation of the InChI that is not human-understandable.

Note: This is sometimes referred to as a hashed InChI.
Source:
PAC, 2016, 88, 239. (Glossary of terms used in computational drug design, part II (IUPAC Recommendations 2015)) on page 248 [Terms] [Paper]