diff --git a/Cargo.toml b/Cargo.toml
index bf4f016..1222db2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,8 +10,8 @@ homepage      = "https://github.com/SpinResearch/merkle_sigs.rs"
 repository    = "https://github.com/SpinResearch/merkle_sigs.rs"
 
 [dependencies]
-ring = "^0.16.1"
-lamport_sigs = "^0.7.0"
+ring         = "0.16.15"
+lamport_sigs = "0.7.0"
 
 [dependencies.merkle]
 version = "^1.11.0"