Doc crypto #485

Job	Run time
afl-build	4m 11s
audit	8s
all-features	1m 26s
build (linux)	1s
clippy	3m 51s
fmt	10s
build (macos)	1s
long-tests	4m 2s
build (windows)	1s
publish-dry-run	11s
test-bindings-c-cpp-linux	53s
test-bindings-c-cpp-windows (Debug-c, x86_64-pc-windows-msvc)	49s
test-bindings-c-cpp-windows (Debug-c, i686-pc-windows-msvc)	55s
test-bindings-c-cpp-windows (Release-c, x86_64-pc-windows-msvc)	58s
test-bindings-c-cpp-windows (Release-c, i686-pc-windows-msvc)	54s
test-bindings-c-cpp-windows (Debug-cpp, x86_64-pc-windows-msvc)	46s
test-bindings-c-cpp-windows (Debug-cpp, i686-pc-windows-msvc)	50s
test-bindings-c-cpp-windows (Release-cpp, x86_64-pc-windows-msvc)	48s
test-bindings-c-cpp-windows (Release-cpp, i686-pc-windows-msvc)	44s
	21m 39s

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