fixup! fix: apply suggestions from code review (#22)

Cargo.toml

@@ -40,19 +40,19 @@ enumflags2 = { version = "^0.7", default-features = false }
 rand = { version = "^0.8", default-features = false }
 openssl = { version = "^0.10", optional = true }
 lazy_static = "1.4.0"
-aes-gcm = { version = "0.10.3", optional = true }
-typenum = { version = "1.17.0", optional = true, features = ["const-generics"] }
-crypto-common = { version = "0.1.6", optional = true }
-aead = { version = "0.5.2", optional = true }
-aes-kw = { version = "0.2.1", optional = true, features = ["alloc"] }
-aes = { version = "0.8.4", optional = true }
-hmac = { version = "0.12.1", optional = true }
-digest = { version = "0.10.7", optional = true }
-sha2 = { version = "0.10.8", optional = true }
-elliptic-curve = { version = "0.13.8", optional = true }
-ecdsa = { version = "0.16.9", optional = true, features = ["sha2"] }
-p256 = { version = "0.13.2", optional = true }
-p384 = { version = "0.13.0", optional = true }
+aes-gcm = { version = "0.10.3", optional = true, default-features = false, features = ["alloc", "aes"] }
+typenum = { version = "1.17.0", optional = true, default-features = false, features = ["const-generics"] }
+crypto-common = { version = "0.1.6", optional = true, default-features = false }
+aead = { version = "0.5.2", optional = true, default-features = false }
+aes-kw = { version = "0.2.1", optional = true, default-features = false, features = ["alloc"] }
+aes = { version = "0.8.4", optional = true, default-features = false }
+hmac = { version = "0.12.1", optional = true, default-features = false }
+digest = { version = "0.10.7", optional = true, default-features = false }
+sha2 = { version = "0.10.8", optional = true, default-features = false }
+elliptic-curve = { version = "0.13.8", default-features = false, optional = true }
+ecdsa = { version = "0.16.9", optional = true, default-features = false, features = ["sha2"] }
+p256 = { version = "0.13.2", optional = true, default-features = false, features = ["alloc", "ecdsa", "arithmetic"] }
+p384 = { version = "0.13.0", optional = true, default-features = false, features = ["alloc", "ecdsa", "arithmetic"] }
 # P-521 must implement DigestPrimitive in order to be usable in ECDSA, which was only recently added and is not released yet.
 # p521 = { version = "0.14.0-pre.1", optional = true }