feat(zeroize): added zeorizing to Felt (#100)

Author: Trantorian1

crates/starknet-types-core/Cargo.toml

@@ -24,6 +24,7 @@ serde = { version = "1", optional = true, default-features = false, features = [
 lambdaworks-crypto = { version = "0.10.0", default-features = false, optional = true }
 parity-scale-codec = { version = "3.6", default-features = false, optional = true }
 lazy_static = { version = "1.5", default-features = false, optional = true }
+zeroize = { version = "1.8.1", default-features = false, optional = true }
 
 [features]
 default = ["std", "serde", "curve", "num-traits"]
@@ -34,8 +35,9 @@ std = [
   "num-integer/std",
   "serde?/std",
   "lambdaworks-crypto?/std",
+  "zeroize?/std",
 ]
-alloc = []
+alloc = ["zeroize?/alloc"]
 curve = []
 hash = ["dep:lambdaworks-crypto"]
 arbitrary = ["std", "dep:arbitrary"]
@@ -44,6 +46,7 @@ serde = ["alloc", "dep:serde"]
 prime-bigint = ["dep:lazy_static"]
 num-traits = []
 papyrus-serialization = ["std"]
+zeroize = ["dep:zeroize"]
 
 [dev-dependencies]
 proptest = "1.5"

crates/starknet-types-core/src/felt/mod.rs

@@ -1057,6 +1057,13 @@ mod errors {
     }
 }
 
+#[cfg(feature = "zeroize")]
+mod zeroing {
+    use super::Felt;
+
+    impl zeroize::DefaultIsZeroes for Felt {}
+}
+
 #[cfg(test)]
 mod test {
     use super::alloc::{format, string::String, vec::Vec};
@@ -1839,4 +1846,14 @@ mod test {
             assert_eq!(Felt::from_bytes_be(&bytes), d);
         }
     }
+
+    #[cfg(feature = "zeroize")]
+    #[test]
+    fn zeroing_felt() {
+        use zeroize::Zeroize;
+
+        let mut felt = Felt::from_hex_unchecked("0x01");
+        felt.zeroize();
+        assert_eq!(felt, Felt::ZERO);
+    }
 }