-ring = { version = "0.17", default-features = false, features = ["alloc"] }
-hex_lit = { version = "0.1", default-features = false, features = ["rust_v_1_46"] }
+ring = { version = "0.17", default-features = false, features = ["alloc"], optional = true }
+hex_lit = { version = "0.1", default-features = false, features = ["rust_v_1_46"], optional = true }