chore: Make more fields public and refactor some signature code

crates/iota-rust-sdk/src/types/checkpoint.rs

@@ -119,7 +119,7 @@ pub struct SignedCheckpointSummary {
 #[cfg_attr(test, derive(test_strategy::Arbitrary))]
 pub struct CheckpointContents(
     #[cfg_attr(test, any(proptest::collection::size_range(0..=2).lift()))]
-    Vec<CheckpointTransactionInfo>,
+    pub  Vec<CheckpointTransactionInfo>,
 );
 
 #[derive(Clone, Debug, PartialEq, Eq)]

crates/iota-rust-sdk/src/types/crypto/mod.rs

@@ -26,6 +26,27 @@ pub use zklogin::{
     ZkLoginInputs, ZkLoginProof, ZkLoginPublicIdentifier,
 };
 
+#[cfg(feature = "serde")]
+#[derive(Debug)]
+pub struct SignatureFromBytesError(String);
+
+#[cfg(feature = "serde")]
+impl SignatureFromBytesError {
+    fn new(msg: impl core::fmt::Display) -> Self {
+        Self(msg.to_string())
+    }
+}
+
+#[cfg(feature = "serde")]
+impl core::fmt::Display for SignatureFromBytesError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "error deserializing bytes: {}", self.0)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl std::error::Error for SignatureFromBytesError {}
+
 // Implement various base64 fixed-size array helpers
 //
 

crates/iota-rust-sdk/src/types/crypto/multisig.rs

@@ -132,7 +132,10 @@ mod serialization {
     use serde_with::{Bytes, DeserializeAs};
 
     use super::*;
-    use crate::types::{Ed25519PublicKey, Secp256k1PublicKey, Secp256r1PublicKey, SignatureScheme};
+    use crate::types::{
+        Ed25519PublicKey, Secp256k1PublicKey, Secp256r1PublicKey, SignatureScheme,
+        crypto::SignatureFromBytesError,
+    };
 
     #[derive(serde_derive::Deserialize)]
     pub struct Multisig {
@@ -203,24 +206,23 @@ mod serialization {
                 })
             } else {
                 let bytes: Cow<'de, [u8]> = Bytes::deserialize_as(deserializer)?;
-                Self::from_serialized_bytes(bytes)
+                Self::from_serialized_bytes(bytes).map_err(serde::de::Error::custom)
             }
         }
     }
 
     impl MultisigAggregatedSignature {
-        pub(crate) fn from_serialized_bytes<T: AsRef<[u8]>, E: serde::de::Error>(
-            bytes: T,
-        ) -> Result<Self, E> {
+        pub fn from_serialized_bytes(
+            bytes: impl AsRef<[u8]>,
+        ) -> Result<Self, SignatureFromBytesError> {
             let bytes = bytes.as_ref();
-            let flag = SignatureScheme::from_byte(
-                *bytes
-                    .first()
-                    .ok_or_else(|| serde::de::Error::custom("missing signature scheme flag"))?,
-            )
-            .map_err(serde::de::Error::custom)?;
+            let flag =
+                SignatureScheme::from_byte(*bytes.first().ok_or_else(|| {
+                    SignatureFromBytesError::new("missing signature scheme flag")
+                })?)
+                .map_err(SignatureFromBytesError::new)?;
             if flag != SignatureScheme::Multisig {
-                return Err(serde::de::Error::custom("invalid multisig flag"));
+                return Err(SignatureFromBytesError::new("invalid multisig flag"));
             }
             let bcs_bytes = &bytes[1..];
 
@@ -231,7 +233,7 @@ mod serialization {
                     committee: multisig.committee,
                 })
             } else {
-                Err(serde::de::Error::custom("invalid multisig"))
+                Err(SignatureFromBytesError::new("invalid multisig"))
             }
         }
     }

crates/iota-rust-sdk/src/types/crypto/passkey.rs

@@ -53,7 +53,7 @@ mod serialization {
     use serde_with::{Bytes, DeserializeAs};
 
     use super::*;
-    use crate::types::{SignatureScheme, SimpleSignature};
+    use crate::types::{SignatureScheme, SimpleSignature, crypto::SignatureFromBytesError};
 
     #[derive(serde::Serialize)]
     struct AuthenticatorRef<'a> {
@@ -121,23 +121,24 @@ mod serialization {
                 let bytes: Cow<'de, [u8]> = Bytes::deserialize_as(deserializer)?;
                 Self::from_serialized_bytes(bytes)
             }
+            .map_err(serde::de::Error::custom)
         }
     }
 
     impl PasskeyAuthenticator {
-        fn try_from_raw<E: serde::de::Error>(
+        fn try_from_raw(
             Authenticator {
                 authenticator_data,
                 client_data_json,
                 signature,
             }: Authenticator,
-        ) -> Result<Self, E> {
+        ) -> Result<Self, SignatureFromBytesError> {
             let SimpleSignature::Secp256r1 {
                 signature,
                 public_key,
             } = signature
             else {
-                return Err(serde::de::Error::custom(
+                return Err(SignatureFromBytesError::new(
                     "expected passkey with secp256r1 signature",
                 ));
             };
@@ -146,7 +147,7 @@ mod serialization {
                 ty: _,
                 challenge,
                 origin: _,
-            } = serde_json::from_str(&client_data_json).map_err(serde::de::Error::custom)?;
+            } = serde_json::from_str(&client_data_json).map_err(SignatureFromBytesError::new)?;
 
             // challenge is 3 byte intent | 32 byte hash
             let mut challenge_buf = [0; 3 + Digest::LENGTH];
@@ -158,7 +159,7 @@ mod serialization {
                 &mut challenge_buf,
             )
             .map_err(|e| {
-                serde::de::Error::custom(format!(
+                SignatureFromBytesError::new(format!(
                     "unable to decode base64urlunpadded into 3-byte intent and 32-byte digest: {e}"
                 ))
             })?;
@@ -176,22 +177,21 @@ mod serialization {
             })
         }
 
-        pub(crate) fn from_serialized_bytes<T: AsRef<[u8]>, E: serde::de::Error>(
-            bytes: T,
-        ) -> Result<Self, E> {
+        pub fn from_serialized_bytes(
+            bytes: impl AsRef<[u8]>,
+        ) -> Result<Self, SignatureFromBytesError> {
             let bytes = bytes.as_ref();
-            let flag = SignatureScheme::from_byte(
-                *bytes
-                    .first()
-                    .ok_or_else(|| serde::de::Error::custom("missing signature scheme flag"))?,
-            )
-            .map_err(serde::de::Error::custom)?;
+            let flag =
+                SignatureScheme::from_byte(*bytes.first().ok_or_else(|| {
+                    SignatureFromBytesError::new("missing signature scheme flag")
+                })?)
+                .map_err(SignatureFromBytesError::new)?;
             if flag != SignatureScheme::Passkey {
-                return Err(serde::de::Error::custom("invalid passkey flag"));
+                return Err(SignatureFromBytesError::new("invalid passkey flag"));
             }
             let bcs_bytes = &bytes[1..];
 
-            let authenticator = bcs::from_bytes(bcs_bytes).map_err(serde::de::Error::custom)?;
+            let authenticator = bcs::from_bytes(bcs_bytes).map_err(SignatureFromBytesError::new)?;
 
             Self::try_from_raw(authenticator)
         }