DNM: OCI layer signature support

src/tardev-snapshotter/Cargo.toml

@@ -20,3 +20,12 @@ tempfile = "3.3.0"
 flate2 = { version = "1.0.26", features = ["zlib-ng"], default-features = false }
 base64 = "0.21.2"
 containerd-client = "0.4.0"
+uuid = { version = "1.0", features = ["v4"] }
+nix = "0.24.2"
+devicemapper = "0.33.1"
+anyhow = "=1.0.58"
+zerocopy = "0.6.1"
+
+# YAML file serialization/deserialization.
+serde = { version = "1.0.159", features = ["derive"] }
+hex = { version = "0.4.3" }