From 778da03f0d80c751a45fc3249d05a2859c4ddfcd Mon Sep 17 00:00:00 2001
From: Daniel Schadt <kingdread@gmx.de>
Date: Wed, 9 Apr 2025 09:19:19 +0200
Subject: fix overflow for long messages

---
 src/block.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'src/block.rs')

diff --git a/src/block.rs b/src/block.rs
index e63062e..abd7ff7 100644
--- a/src/block.rs
+++ b/src/block.rs
@@ -53,6 +53,17 @@ impl Block {
         }
         Block(block)
     }
+
+    /// Computes self * 2^exponent
+    ///
+    /// Ensures that there's no overflow in computing 2^exponent.
+    pub fn exp(&self, exponent: u32) -> Block {
+        match exponent {
+            _ if exponent < 32 => *self * (1 << exponent),
+            _ if exponent % 2 == 0 => self.exp(exponent / 2).exp(exponent / 2),
+            _ => (*self * 2).exp(exponent - 1),
+        }
+    }
 }
 
 impl From<[u8; 16]> for Block {
-- 
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