MAINT: Simplify file identifiers generation #4982

Job	Run time
pytest on windows	6m 38s
Build & verify package	20s
Check code style issues	16s
pytest on 3.7 (crypto-lib: cryptography)	5m 24s
pytest on 3.8 (crypto-lib: cryptography)	5m 19s
pytest on 3.9 (crypto-lib: cryptography)	5m 5s
pytest on 3.10 (crypto-lib: cryptography)	5m 51s
pytest on 3.11 (crypto-lib: cryptography)	5m 17s
pytest on 3.12 (crypto-lib: cryptography)	6m 35s
pytest on 3.7 (crypto-lib: pycryptodome)	5m 5s
pytest on 3.7 (crypto-lib: none)	4m 50s
Combine & check coverage.	14s
	50m 54s

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