diff --git a/Cargo.toml b/Cargo.toml
index 26dfff7..d3862ca 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ coverm = "0.6.0"
 ndarray = "0.13.1"
 numpy = "0.12.1"
 pyo3 = { version = "0.12.4", features = ["extension-module"] }
+openssl = { version = "0.10", features = ["vendored"] }
 rust-htslib = "0.36.0"
 
 [package.metadata.maturin]