openpgp: Use time-constant comparison for MDC.

  - This avoids side-channel attacks on the MDC computed digest.

1 files changed, 4 insertions, 1 deletions

diff --git a/openpgp/src/packet/mdc.rs b/openpgp/src/packet/mdc.rs
index 16fdcd7b..5c3544ca 100644
--- a/openpgp/src/packet/mdc.rs
+++ b/openpgp/src/packet/mdc.rs
@@ -1,4 +1,7 @@
+use std::cmp::Ordering;
+
 use crate::crypto;
+use crate::crypto::mem;
 use crate::packet;
 use crate::Packet;
 
@@ -67,7 +70,7 @@ impl MDC {
             // return false.
             false
         } else {
-            self.computed_digest == self.digest
+            mem::secure_cmp(&self.computed_digest, &self.digest) == Ordering::Equal
         }
     }
 }