Fixes#6277
Description:
Make each of the five EdDSA instances defined in RFC 8032 -- Ed25519,
Ed25519ctx, Ed25519ph, Ed448, Ed448ph -- available via the EVP APIs.
The desired EdDSA instance is specified via an OSSL_PARAM.
All instances, except for Ed25519, allow context strings as input.
Context strings are passed via an OSSL_PARAM. For Ed25519ctx, the
context string must be nonempty.
Ed25519, Ed25519ctx, Ed448 are PureEdDSA instances, which means that
the full message (not a digest) must be passed to sign and verify
operations.
Ed25519ph, Ed448ph are HashEdDSA instances, which means that the input
message is hashed before sign and verify.
Testing:
All 21 test vectors from RFC 8032 have been added to evppkey_ecx.txt
(thanks to Shane Lontis for showing how to do that). Those 21 test
vectors are exercised by evp_test.c and cover all five instances.
Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/19705)