Doc crypto #474

Job	Run time
afl-build	4m 50s
all-features	1m 34s
audit	10s
build (linux)	1m 58s
build (macos)	2m 11s
clippy	3m 40s
build (windows)	4m 56s
fmt	8s
long-tests	4m 5s
publish-dry-run	5s
test-bindings-c-cpp-linux	53s
test-bindings-c-cpp-windows (Debug-c, x86_64-pc-windows-msvc)	2m 56s
test-bindings-c-cpp-windows (Debug-c, i686-pc-windows-msvc)	2m 44s
test-bindings-c-cpp-windows (Release-c, x86_64-pc-windows-msvc)	2m 22s
test-bindings-c-cpp-windows (Release-c, i686-pc-windows-msvc)	2m 33s
test-bindings-c-cpp-windows (Debug-cpp, x86_64-pc-windows-msvc)	2m 30s
test-bindings-c-cpp-windows (Debug-cpp, i686-pc-windows-msvc)	2m 45s
test-bindings-c-cpp-windows (Release-cpp, x86_64-pc-windows-msvc)	2m 20s
test-bindings-c-cpp-windows (Release-cpp, i686-pc-windows-msvc)	2m 25s
	45m 5s

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