Revamp error handling (#63)

* revamp encapsulate error

* revamp hkdf error

* update license

* update dep

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ecies"
-version = "0.2.0"
+version = "0.2.1"
 # docs
 authors = ["Weiliang Li <[email protected]>"]
 description = "Elliptic Curve Integrated Encryption Scheme for secp256k1 in Rust"
@@ -25,11 +25,11 @@ libsecp256k1 = "0.3.5"
 sha2 = "0.9.2"
 
 # openssl aes
-openssl = {version = "0.10.31", optional = true}
+openssl = {version = "0.10.32", optional = true}
 
 # pure rust aes
 aes-gcm = {version = "0.8.0", optional = true}
-typenum = {version = "1.12", optional = true}
+typenum = {version = "1.12.0", optional = true}
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 rand = {version = "0.7.3", features = ["wasm-bindgen"]}
@@ -50,8 +50,8 @@ wasm-bindgen-test = "0.3.19"
 
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 futures-util = "0.3.8"
-reqwest = "0.10.9"
-tokio = "0.2.22"
+reqwest = "0.10.10"
+tokio = "0.2.24"
 
 [[bench]]
 harness = false

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2019-2020 Weiliang Li
+Copyright (c) 2019-2021 Weiliang Li
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

src/lib.rs

@@ -76,7 +76,7 @@ pub fn encrypt(receiver_pub: &[u8], msg: &[u8]) -> Result<Vec<u8>, SecpError> {
     let receiver_pk = PublicKey::parse_slice(receiver_pub, None)?;
     let (ephemeral_sk, ephemeral_pk) = generate_keypair();
 
-    let aes_key = encapsulate(&ephemeral_sk, &receiver_pk);
+    let aes_key = encapsulate(&ephemeral_sk, &receiver_pk)?;
     let encrypted = aes_encrypt(&aes_key, msg).ok_or(SecpError::InvalidMessage)?;
 
     let mut cipher_text = Vec::with_capacity(FULL_PUBLIC_KEY_SIZE + encrypted.len());
@@ -102,7 +102,7 @@ pub fn decrypt(receiver_sec: &[u8], msg: &[u8]) -> Result<Vec<u8>, SecpError> {
     let ephemeral_pk = PublicKey::parse_slice(&msg[..FULL_PUBLIC_KEY_SIZE], None)?;
     let encrypted = &msg[FULL_PUBLIC_KEY_SIZE..];
 
-    let aes_key = decapsulate(&ephemeral_pk, &receiver_sk);
+    let aes_key = decapsulate(&ephemeral_pk, &receiver_sk)?;
 
     aes_decrypt(&aes_key, encrypted).ok_or(SecpError::InvalidMessage)
 }

src/utils.rs

@@ -1,6 +1,6 @@
 use hkdf::Hkdf;
 use rand::thread_rng;
-use secp256k1::{util::FULL_PUBLIC_KEY_SIZE, PublicKey, SecretKey};
+use secp256k1::{util::FULL_PUBLIC_KEY_SIZE, Error as SecpError, PublicKey, SecretKey};
 use sha2::Sha256;
 
 use crate::consts::EMPTY_BYTES;
@@ -19,9 +19,9 @@ pub fn generate_keypair() -> (SecretKey, PublicKey) {
 }
 
 /// Calculate a shared AES key of our secret key and peer's public key by hkdf
-pub fn encapsulate(sk: &SecretKey, peer_pk: &PublicKey) -> AesKey {
+pub fn encapsulate(sk: &SecretKey, peer_pk: &PublicKey) -> Result<AesKey, SecpError> {
     let mut shared_point = peer_pk.clone();
-    shared_point.tweak_mul_assign(&sk).unwrap();
+    shared_point.tweak_mul_assign(&sk)?;
 
     let mut master = Vec::with_capacity(FULL_PUBLIC_KEY_SIZE * 2);
     master.extend(PublicKey::from_secret_key(&sk).serialize().iter());
@@ -31,9 +31,9 @@ pub fn encapsulate(sk: &SecretKey, peer_pk: &PublicKey) -> AesKey {
 }
 
 /// Calculate a shared AES key of our public key and peer's secret key by hkdf
-pub fn decapsulate(pk: &PublicKey, peer_sk: &SecretKey) -> AesKey {
+pub fn decapsulate(pk: &PublicKey, peer_sk: &SecretKey) -> Result<AesKey, SecpError> {
     let mut shared_point = pk.clone();
-    shared_point.tweak_mul_assign(&peer_sk).unwrap();
+    shared_point.tweak_mul_assign(&peer_sk)?;
 
     let mut master = Vec::with_capacity(FULL_PUBLIC_KEY_SIZE * 2);
     master.extend(pk.serialize().iter());
@@ -43,11 +43,12 @@ pub fn decapsulate(pk: &PublicKey, peer_sk: &SecretKey) -> AesKey {
 }
 
 // private below
-fn hkdf_sha256(master: &[u8]) -> AesKey {
+fn hkdf_sha256(master: &[u8]) -> Result<AesKey, SecpError> {
     let h = Hkdf::<Sha256>::new(None, master);
     let mut out = [0u8; 32];
-    h.expand(&EMPTY_BYTES, &mut out).unwrap();
-    out
+    h.expand(&EMPTY_BYTES, &mut out)
+        .map_err(|_| SecpError::InvalidInputLength)?;
+    Ok(out)
 }
 
 #[cfg(test)]
@@ -176,7 +177,7 @@ pub(crate) mod tests {
 
         assert_eq!(encapsulate(&sk2, &pk3), decapsulate(&pk2, &sk3));
         assert_eq!(
-            encapsulate(&sk2, &pk3).to_vec(),
+            encapsulate(&sk2, &pk3).map(|v| v.to_vec()).unwrap(),
             decode_hex("6f982d63e8590c9d9b5b4c1959ff80315d772edd8f60287c9361d548d5200f82")
         );
     }