From 692f26a354e27339598e25ae21ac6545e4aa4b65 Mon Sep 17 00:00:00 2001 From: Justus Winter Date: Wed, 6 Oct 2021 14:31:34 +0200 Subject: openpgp: Add Curve::field_size. --- openpgp/src/types/mod.rs | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'openpgp/src') diff --git a/openpgp/src/types/mod.rs b/openpgp/src/types/mod.rs index e87a0e2c..29775a16 100644 --- a/openpgp/src/types/mod.rs +++ b/openpgp/src/types/mod.rs @@ -347,6 +347,28 @@ impl Curve { Unknown(_) => None, } } + + /// Returns the curve's field size in bytes. + /// + /// # Examples + /// + /// ```rust + /// # fn main() -> sequoia_openpgp::Result<()> { + /// use sequoia_openpgp as openpgp; + /// use openpgp::types::Curve; + /// + /// assert_eq!(Curve::NistP256.field_size()?, 32); + /// assert_eq!(Curve::NistP384.field_size()?, 48); + /// assert_eq!(Curve::NistP521.field_size()?, 66); + /// assert_eq!(Curve::Ed25519.field_size()?, 32); + /// assert!(Curve::Unknown(Box::new([0x2B, 0x11])).field_size().is_err()); + /// # Ok(()) } + /// ``` + pub fn field_size(&self) -> Result { + self.bits() + .map(|bits| (bits + 7) / 8) + .ok_or_else(|| Error::UnsupportedEllipticCurve(self.clone()).into()) + } } impl fmt::Display for Curve { -- cgit v1.2.3