diff --git a/pyproject.toml b/pyproject.toml
index 8c44af68..d40add6a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -40,6 +40,7 @@ dependencies = [
   "cryptography",
   "in-toto-attestation",
   "oras>=0.2.30",
+  "pyasn1>=0.6.2",
   "sigstore>=4.2",
   "sigstore-models>=0.0.5",
   "typing_extensions",