EC_POINT_get_affine_coordinates replacement in 3.0

[William Roberts]

On Tue, May 3, 2022 at 3:18 PM Chris Bare <chris.bare at gmail.com> wrote:
>
>
> On Tue, May 3, 2022 at 3:10 PM William Roberts <bill.c.roberts at gmail.com> wrote:
>>
>> On Tue, May 3, 2022 at 1:14 PM Chris Bare <chris.bare at gmail.com> wrote:
>> >
>> > I'm converting some openssl 1.0 code to 3.0 and I don't know how to get the coordinates
>> > in a 3.0 way.
>> > The old code is:
>> > BN_CTX *ctx = BN_CTX_new ();
>> > BIGNUM *X = NULL, *Y = NULL;
>> > const EC_POINT *pubkey;
>> > const EC_GROUP *group;
>> > BN_CTX_start (ctx);
>> > X = BN_CTX_get (ctx);
>> > Y = BN_CTX_get (ctx);
>> > pubkey = EC_KEY_get0_public_key ((EC_KEY *) EVP_PKEY_get0 (pkey));
>> > group = EC_KEY_get0_group ((EC_KEY *) EVP_PKEY_get0 (cvr->sm_pkey));
>> > EC_POINT_get_affine_coordinates_GFp (group, pubkey, X, Y, ctx)
>> >
>> > What would be the 3.0 way to get X and Y without using deprecated functions?
>>
>> For EC_POINT_get_affine_coordinates_GFp it goes to
>> EC_POINT_get_affine_coordinates, see:
>>   - https://www.openssl.org/docs/man3.0/man3/EC_POINT_get_affine_coordinates.html
>>
>> Offhand I don't see any other deprecated functions, was that the only one?
>>
>> Thanks,
>> Bill
>
>
> all the EC_KEY_get0_ functions are deprecated. Is there a new way to access the internals of
> the opaque structures, or am I stuck with the deprecated ones for this?

I think you want the from and to data routines that provide the
components from an EVP PKEY or produce an EVP_PKEY
from the components:
  - https://www.openssl.org/docs/man3.0/man3/EVP_PKEY_todata.html
  - https://www.openssl.org/docs/man3.0/man3/EVP_PKEY_fromdata.html