From 2561bdf64d1e2ea1b2f9de30c3fc805953413e20 Mon Sep 17 00:00:00 2001
From: Rushil Mehra <rmehra@cloudflare.com>
Date: Mon, 10 Feb 2025 13:50:50 -0800
Subject: [PATCH] Expose EVP_HPKE_KEY

---
 boring/src/hpke.rs | 31 +++++++++++++++++++++++++++++++
 boring/src/lib.rs  |  1 +
 2 files changed, 32 insertions(+)
 create mode 100644 boring/src/hpke.rs

diff --git a/boring/src/hpke.rs b/boring/src/hpke.rs
new file mode 100644
index 00000000..7f788224
--- /dev/null
+++ b/boring/src/hpke.rs
@@ -0,0 +1,31 @@
+use crate::error::ErrorStack;
+use crate::{cvt_0i, cvt_p, ffi};
+
+use foreign_types::ForeignType;
+
+foreign_type_and_impl_send_sync! {
+    type CType = ffi::EVP_HPKE_KEY;
+    fn drop = ffi::EVP_HPKE_KEY_free;
+
+    pub struct HpkeKey;
+}
+
+impl HpkeKey {
+    /// Allocates and initializes a key with the `EVP_HPKE_KEY` type using the
+    /// `EVP_hpke_x25519_hkdf_sha256` KEM algorithm.
+    pub fn dhkem_p256_sha256(pkey: &[u8]) -> Result<HpkeKey, ErrorStack> {
+        unsafe {
+            ffi::init();
+            let hpke = cvt_p(ffi::EVP_HPKE_KEY_new()).map(|p| HpkeKey::from_ptr(p))?;
+
+            cvt_0i(ffi::EVP_HPKE_KEY_init(
+                hpke.as_ptr(),
+                ffi::EVP_hpke_x25519_hkdf_sha256(),
+                pkey.as_ptr(),
+                pkey.len(),
+            ))?;
+
+            Ok(hpke)
+        }
+    }
+}
diff --git a/boring/src/lib.rs b/boring/src/lib.rs
index 6779586a..93d56943 100644
--- a/boring/src/lib.rs
+++ b/boring/src/lib.rs
@@ -128,6 +128,7 @@ pub mod error;
 pub mod ex_data;
 pub mod fips;
 pub mod hash;
+pub mod hpke;
 pub mod memcmp;
 pub mod nid;
 pub mod pkcs12;