diff --git a/rust/ic_principal/src/lib.rs b/rust/ic_principal/src/lib.rs
index 237560a5..9860e8b9 100644
--- a/rust/ic_principal/src/lib.rs
+++ b/rust/ic_principal/src/lib.rs
@@ -97,7 +97,7 @@ pub struct Principal {
 }
 
 impl Principal {
-    const MAX_LENGTH_IN_BYTES: usize = 29;
+    pub const MAX_LENGTH_IN_BYTES: usize = 29;
     const CRC_LENGTH_IN_BYTES: usize = 4;
 
     const SELF_AUTHENTICATING_TAG: u8 = 2;