diff --git a/sha1/Cargo.toml b/sha1/Cargo.toml
index dcb6e049..af002663 100644
--- a/sha1/Cargo.toml
+++ b/sha1/Cargo.toml
@@ -29,7 +29,6 @@ std = ["digest/std"]
 oid = ["digest/oid"] # Enable OID support
 zeroize = ["digest/zeroize"]
 force-soft = [] # Force software implementation
-collision = ["digest/mac"] # Detect SHA1 collisions and mitigate them
 
 [package.metadata.docs.rs]
 all-features = true