Crunchy uses this format for ephemeral points in hybrid encryption.

PiperOrigin-RevId: 205294945
GitOrigin-RevId: 8e670c4bef2084717a8d149a646b4e4a3c790a0b

PiperOrigin-RevId: 204232671
GitOrigin-RevId: 33ca66ee5ff8124dd3951ea390c5c8572b058d6c

Removing references to NIST P-224 and SHA224, which we never supported and are not used in many places.

We keep SHA1 because HMAC-SHA1 is safe and a popular MAC.

PiperOrigin-RevId: 193747110
GitOrigin-RevId: 2f657666903fc8e7c3963017a7462ac33bb7b20d

PiperOrigin-RevId: 189379168
GitOrigin-RevId: 2524f3b25fbaa08011b512a2730265435f48db37

Also putting all subtle-classes in namespace crypto::tink::subtle.

Change-Id: I47fece5df4ef524521449320d619b13ba8466373
ORIGINAL_AUTHOR=Bartosz Przydatek <przydatek@google.com>
GitOrigin-RevId: 39ba523aecf79247e31f87e974f79eec3dfaf1bc