From e3c2455f636b54267aa3b155bfff5ac4033489b1 Mon Sep 17 00:00:00 2001
From: Michael Rosenberg <micro@fastmail.com>
Date: Tue, 8 Jul 2025 15:06:07 -0400
Subject: [PATCH] x: Remove Zeroize impl for secret types (#782)

---
 x25519-dalek/CHANGELOG.md  |  4 ++++
 x25519-dalek/src/x25519.rs | 28 ----------------------------
 2 files changed, 4 insertions(+), 28 deletions(-)

diff --git a/x25519-dalek/CHANGELOG.md b/x25519-dalek/CHANGELOG.md
index 10e1a54..6695492 100644
--- a/x25519-dalek/CHANGELOG.md
+++ b/x25519-dalek/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 Entries are listed in reverse chronological order.
 
+## Unreleased
+
+* Remove `Zeroize` impl for `x25519::{EphemeralSecret, ReusableSecret, SharedSecret, StaticSecret}` to prevent misuse. These are now only zeroized on drop.
+
 # 2.x Series
 
 * Note: All `x255919-dalek` 2.x releases are in sync with the underlying `curve25519-dalek` 4.x releases. 
diff --git a/x25519-dalek/src/x25519.rs b/x25519-dalek/src/x25519.rs
index c1f8281..2d155f0 100644
--- a/x25519-dalek/src/x25519.rs
+++ b/x25519-dalek/src/x25519.rs
@@ -111,13 +111,6 @@ impl<'a> From<&'a EphemeralSecret> for PublicKey {
 impl Drop for EphemeralSecret {
     fn drop(&mut self) {
         #[cfg(feature = "zeroize")]
-        self.zeroize();
-    }
-}
-
-#[cfg(feature = "zeroize")]
-impl Zeroize for EphemeralSecret {
-    fn zeroize(&mut self) {
         self.0.zeroize();
     }
 }
@@ -182,13 +175,6 @@ impl<'a> From<&'a ReusableSecret> for PublicKey {
 impl Drop for ReusableSecret {
     fn drop(&mut self) {
         #[cfg(feature = "zeroize")]
-        self.zeroize();
-    }
-}
-
-#[cfg(all(feature = "reusable_secrets", feature = "zeroize"))]
-impl Zeroize for ReusableSecret {
-    fn zeroize(&mut self) {
         self.0.zeroize();
     }
 }
@@ -279,13 +265,6 @@ impl AsRef<[u8]> for StaticSecret {
 impl Drop for StaticSecret {
     fn drop(&mut self) {
         #[cfg(feature = "zeroize")]
-        self.zeroize();
-    }
-}
-
-#[cfg(all(feature = "static_secrets", feature = "zeroize"))]
-impl Zeroize for StaticSecret {
-    fn zeroize(&mut self) {
         self.0.zeroize();
     }
 }
@@ -362,13 +341,6 @@ impl AsRef<[u8]> for SharedSecret {
 impl Drop for SharedSecret {
     fn drop(&mut self) {
         #[cfg(feature = "zeroize")]
-        self.zeroize();
-    }
-}
-
-#[cfg(feature = "zeroize")]
-impl Zeroize for SharedSecret {
-    fn zeroize(&mut self) {
         self.0.zeroize();
     }
 }