[openssl-users] ec_point_is_compat

[john.hughes at secid.co.uk]

In a test harness I'm writing I'm adding in a facility to check the validity
of an EC public key according to the 4 tests of X9.62.

 

The curve and point I supply to EC_POINT_is_at_infinity works fine.

 

However, when I come to use EC_POINT_is_on_curve it fails. The error return
indicates the error is "incompatible objects". Looking through the openssl
source indicates that the error is a result of failing one of the tests in
the inline function ec_point_is_compat.  In this function there are four
simple tests - most of which pertains to looking at the values of curve_name
in the EC_POINT and EC_GROUP structures.  So I thought, quite simply, look
at what these two structures hold pertaining to the member curve_name - and
then I can figure out what I'm doing wrong.

 

The openssl interface has the function EC_GROUP_get_curve_name() which I
used to show that curve name was 409 (for NIST P192) and 415 (for NIST
P256). But to my surprise there was no function of
EC_POINT_get_curve_name().

 

Has any one any suggestions why my code is failing the ec_point_is_compat
tests and how to get hold of the values of meth and curve_name in my
EC_GROUP and EC_POINT structures so I can determine why the checks are
failing

 

 

John

 

 

 

 

 

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