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

Commit Message

Stefan Berger Feb. 23, 2024, 8:41 p.m. UTC

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 <[e-mail]>
---
 include/crypto/ecc_curve.h | 3 +++
 1 file changed, 3 insertions(+)

Patch

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;