[PATCH] lib/crypto: Add a sentence about zeroizing raw key structures
From: Thomas Huth
Date: Wed Nov 04 2026 - 05:54:07 EST
Let's make it clear that raw key material has to be zeroized, too.
Suggested-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
---
Suggested here:
https://lore.kernel.org/linux-crypto/20260930201434.GA61218@xxxxxxxxxx/
Documentation/crypto/libcrypto-zeroization.rst | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/crypto/libcrypto-zeroization.rst b/Documentation/crypto/libcrypto-zeroization.rst
index 76b6506711634..fe9f94413d1f2 100644
--- a/Documentation/crypto/libcrypto-zeroization.rst
+++ b/Documentation/crypto/libcrypto-zeroization.rst
@@ -47,7 +47,9 @@ The following types of structures hold sensitive material and should be
zeroized after use:
- **Key structures** (e.g. ``struct aes_key``, ``struct hmac_sha256_key``):
- contain expanded round keys or prepared key material.
+ contain expanded round keys or prepared key material. Note: Arrays and
+ structures that contain raw key material (e.g. raw AES keys) of course
+ need to be zeroized as well as soon as the data is not required anymore.
- **HMAC/MAC context structures** (e.g. ``struct hmac_sha256_ctx``,
``struct aes_cmac_ctx``): contain inner and outer hash states derived from
--
2.56.0