[PATCH v3 05/10] crypto: ecc - Add nbits field to ecc_curve structure

Stefan Berger
2024-02-23T20:42:16Z

Add the number of bits a curve has to the ecc_curve definition. This field
only needs to be set for curves that don't fill up all bytes in their
digits, such as NIST P521 which has only 9 bits in the most significant
digit. This field will be used to determine the number of bytes a curve
requires for its key coordinates for example.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
include/crypto/ecc_curve.h | 3 +++
1 file changed, 3 insertions(+)

diff --git a/include/crypto/ecc_curve.h b/include/crypto/ecc_curve.h
index 70964781eb68..337a44956926 100644
--- a/include/crypto/ecc_curve.h
+++ b/include/crypto/ecc_curve.h
@@ -23,6 +23,8 @@ struct ecc_point {
* struct ecc_curve - definition of elliptic curve
*
* @name: Short name of the curve.
+ * @nbits: Curves that do not use all bits in their ndigits must specify
+ * their number of bits here, otherwise can leave at 0.
* @g: Generator point of the curve.
* @p: Prime number, if Barrett's reduction is used for this curve
* pre-calculated value 'mu' is appended to the @p after ndigits.
@@ -34,6 +36,7 @@ struct ecc_point {
*/
struct ecc_curve {
char *name;
+ unsigned int nbits;
struct ecc_point g;
u64 *p;
u64 *n;
--
2.43.0