From 2c5347d385b62d7d1ec7de1a6b9ee70a23f048be Mon Sep 17 00:00:00 2001
From: crwn1337 <38888474+crwn1337@users.noreply.github.com>
Date: Thu, 31 Aug 2023 18:18:57 +0300
Subject: [PATCH] add voprf to p521

---
 Cargo.lock      | 1 +
 p521/Cargo.toml | 2 ++
 p521/src/lib.rs | 9 +++++++++
 3 files changed, 12 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index b2ddf688..d2ec03bc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -790,6 +790,7 @@ version = "0.13.0"
 dependencies = [
  "elliptic-curve",
  "primeorder",
+ "sha2",
 ]
 
 [[package]]
diff --git a/p521/Cargo.toml b/p521/Cargo.toml
index f80160e8..8786301c 100644
--- a/p521/Cargo.toml
+++ b/p521/Cargo.toml
@@ -17,6 +17,7 @@ rust-version = "1.65"
 
 [dependencies]
 elliptic-curve = { version = "0.13", default-features = false, features = ["hazmat", "sec1"] }
+sha2 = { version = "0.10", optional = true, default-features = false }
 
 # optional dependencies
 primeorder = { version = "0.13.1", optional = true, path = "../primeorder" }
@@ -30,6 +31,7 @@ jwk = ["elliptic-curve/jwk"]
 pem = ["elliptic-curve/pem", "pkcs8"]
 pkcs8 = ["elliptic-curve/pkcs8"]
 wip-arithmetic-do-not-use = ["dep:primeorder"]
+voprf = ["elliptic-curve/voprf", "sha2"]
 
 [package.metadata.docs.rs]
 all-features = true
diff --git a/p521/src/lib.rs b/p521/src/lib.rs
index dc9859b2..fb127ca7 100644
--- a/p521/src/lib.rs
+++ b/p521/src/lib.rs
@@ -78,3 +78,12 @@ impl FieldBytesEncoding<NistP521> for U576 {}
 
 /// NIST P-521 secret key.
 pub type SecretKey = elliptic_curve::SecretKey<NistP521>;
+
+#[cfg(feature = "voprf")]
+impl elliptic_curve::VoprfParameters for NistP521 {
+    /// See <https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-19.html#section-4.5-1>.
+    const ID: &'static str = "P521-SHA512";
+
+    /// See <https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-08.html#section-4.5-1.2>.
+    type Hash = sha2::Sha512;
+}