diff --git b/src/untrusted.rs a/src/untrusted.rs
index 010b001..47c281e 100644
--- b/src/untrusted.rs
+++ a/src/untrusted.rs
@@ -105,6 +105,10 @@
 #![allow(rustdoc::bare_urls)]
 #![no_std]
 
+// ANDROID: use std to allow building as a dylib.
+#[cfg(android_dylib)]
+extern crate std;
+
 /// A wrapper around `&'a [u8]` that helps in writing panic-free code.
 ///
 /// No methods of `Input` will ever panic.