diff --git a/src/lib.rs b/src/lib.rs
index bec82a2b6..4a76bafb9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,6 @@
 #[macro_use]
 extern crate slog;
 
+pub mod pubkeystore;
 pub mod state;
 pub mod utils;
diff --git a/src/pubkeystore/mod.rs b/src/pubkeystore/mod.rs
new file mode 100644
index 000000000..414c9e7fa
--- /dev/null
+++ b/src/pubkeystore/mod.rs
@@ -0,0 +1,7 @@
+use super::state::block::Block;
+
+#[allow(unused_variables)]
+pub fn verify_block(block: &Block, proposer: &usize) -> bool {
+    // TODO: fetch proposer pubkey and verify it.
+    return true;
+}
diff --git a/src/state/mod.rs b/src/state/mod.rs
index 922b54aa2..72830910f 100644
--- a/src/state/mod.rs
+++ b/src/state/mod.rs
@@ -4,6 +4,7 @@ extern crate blake2;
 extern crate bytes;
 
 use super::utils;
+use super::pubkeystore;
 
 pub mod active_state;
 pub mod crystallized_state;