[openssl-users] What does EC_KEY_get0_public_key deliver?

Christian Weber weber at infotech.de
Thu Jan 8 17:16:08 UTC 2015

Dear OpenSSL-Users,

recently i found a pitfall using EC_KEY_get0_public_key(key->pkey.ec).
The function just returns a copy to a pointer to key->pub_key which is a 
EC_POINT pointer.
The key itself is taken from a certificate using EVP_PKEY *key = 

Fine, i assumed, these must be coordinates of the publich key in the 
elements X and Y!
Both are BIGNUMS as expected.

BUT instead i got some tranformed coordinates.

Finally i got the coordinates by using EC_POINT_point2hex() with the 
propoer group and
converting its output.

There seems to be no instantly accessible BIGNUM-pair represesentation 
of a ECDSA
public key, which i would like to gain access to.

What am i missing?

Thanks in advance
-- Chris

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