40 implement a secure key storage functionality for the pop server

crates/keystore/Cargo.toml

@@ -10,3 +10,10 @@ chrono.workspace = true
 serde_json.workspace = true
 thiserror.workspace = true
 nix.workspace = true
+chacha20poly1305 = "0.10.1"
+log = "0.4.22"
+openssl = "0.10.66"
+jsonwebtoken = "9.3.0"
+zeroize.workspace = true
+secrecy = "0.10.2"
+

crates/keystore/src/errors.rs

@@ -0,0 +1,23 @@
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum KeystoreError {
+    #[error("File error: {0}")]
+    FileError(std::io::Error),
+    #[error("JwkConversionError")] 
+    JwkConversionError,
+    #[error("KeyPairGenerationError")]
+    KeyPairGenerationError,
+    #[error("non compliant")]
+    NonCompliant,
+    #[error("not found")]
+    NotFound,
+    #[error("parse error")]
+    ParseError(serde_json::Error),
+    #[error("serde error")]
+    SerdeError(serde_json::Error),
+    #[error("Encryption error: {0}")]
+    EncryptionError(chacha20poly1305::Error),
+    #[error("Decryption error: {0}")]
+    DecryptionError(chacha20poly1305::Error),
+}

crates/keystore/src/lib.rs

@@ -1,31 +1,15 @@
 pub mod filesystem;
+pub mod errors;
 
 use chrono::Utc;
 use did_utils::{
     crypto::{Ed25519KeyPair, Generate, ToPublic, X25519KeyPair},
     jwk::Jwk,
 };
-use std::error::Error;
+use std::{error::Error, fs::File, io::{Read, Write}};
 
 use crate::filesystem::FileSystem;
-
-#[derive(Debug, thiserror::Error)]
-pub enum KeyStoreError {
-    #[error("failure to convert to JWK format")]
-    JwkConversionError,
-    #[error("failure to generate key pair")]
-    KeyPairGenerationError,
-    #[error("ioerror: {0}")]
-    IoError(std::io::Error),
-    #[error("non compliant")]
-    NonCompliant,
-    #[error("not found")]
-    NotFound,
-    #[error("parse error")]
-    ParseError(serde_json::Error),
-    #[error("serde error")]
-    SerdeError(serde_json::Error),
-}
+use crate::errors::KeystoreError;
 
 pub struct KeyStore<'a> {
     fs: &'a mut dyn FileSystem,
@@ -34,6 +18,76 @@
     keys: Vec<Jwk>,
 }
 
+use chacha20poly1305::{
+    aead::{generic_array::GenericArray, Aead, AeadCore, OsRng},
+    ChaCha20Poly1305, KeyInit,
+};
+
+use log::{debug, info, error}; // Import logging macros
+use secrecy::{ExposeSecret, SecretString};
+use zeroize::Zeroize;
+
+struct FileSystemKeystore {
+    key: SecretString, // Store key securely using secrecy crate
+    nonce: Vec<u8>,
+}
+
+impl FileSystemKeystore {
+    fn encrypt(mut self, secret: KeyStore) -> Result<(), Box<dyn Error>> {
+        let key = self.key.expose_secret(); // Access key securely
+        let cipher = ChaCha20Poly1305::new(GenericArray::from_slice(key.as_bytes()));
+
+        let nonce = ChaCha20Poly1305::generate_nonce(&mut OsRng);
+        let path = secret.path();
+        let mut keystorefile = File::open(path.clone())?; // Use Result for error handling
+
+        let mut buffer = Vec::new();
+        keystorefile.read_to_end(&mut buffer)?; // Use Result for error handling
+
+        let encrypted_key = cipher
+            .encrypt(GenericArray::from_slice(&self.nonce), buffer.as_slice())
+            .map_err(|err| err).unwrap();
+        // Overwrite the file with encrypted keys
+        keystorefile.write_all(&encrypted_key)?; // Use Result for error handling
+
+        self.nonce = nonce.to_vec();
+
+        // Overwrite the buffer with zeros to prevent data leakage
+        buffer.clear();
+        buffer.zeroize();
+
+        // Conditional logging
+        debug!("Encryption successful for keystore file: {}", path);
+
+        Ok(())
+    }
+
+    fn decrypt(self, secret: KeyStore) -> Result<Vec<u8>, std::io::Error> {
+        let key = self.key.expose_secret(); // Access key securely
+        let cipher = ChaCha20Poly1305::new(GenericArray::from_slice(key.as_bytes()));
+
+        let path = secret.path();
+        let mut keystorefile = File::open(path.clone())?; // Use Result for error handling
+
+        let mut buffer = Vec::new();
+        keystorefile.read_to_end(&mut buffer)?; // Use Result for error handling
+
+        let decrypted_key = cipher.decrypt(GenericArray::from_slice(&self.nonce), buffer.as_slice())
+            .map_err(|err| err).unwrap();
+
+        // Enhanced redaction: Replace all sensitive characters with asterisks
+        let redacted_key = decrypted_key.iter().map(|b| if b.is_ascii_graphic() && !b.is_ascii_whitespace() { '*' as u8 } else { *b }).collect::<Vec<u8>>();
+
+        // Conditional logging with redacted key
+        info!("Decryption successful for keystore file: {}, redacted key: {:?}", &path, redacted_key);
+
+        buffer.clear();
+        buffer.zeroize();
+
+        Ok(decrypted_key)
+    }
+}
+
 impl<'a> KeyStore<'a> {
     /// Constructs file-based key-value store.
     pub fn new(fs: &'a mut dyn FileSystem, storage_dirpath: &str) -> Self {
@@ -49,13 +103,13 @@
     pub fn latest(
         fs: &'a mut dyn FileSystem,
         storage_dirpath: &str,
-    ) -> Result<Self, KeyStoreError> {
+    ) -> Result<Self, KeystoreError> {
         let dirpath = format!("{storage_dirpath}/keystore");
 
         // Read directory
         let paths = fs
             .read_dir_files(&dirpath)
-            .map_err(KeyStoreError::IoError)?;
+            .map_err(KeystoreError::FileError)?;
 
         // Collect paths and associated timestamps of files inside `dir`
         let mut collected: Vec<(String, i32)> = vec![];
@@ -65,7 +119,7 @@
                     .trim_start_matches(&format!("{}/", &dirpath))
                     .trim_end_matches(".json")
                     .parse()
-                    .map_err(|_| KeyStoreError::NonCompliant)?;
+                    .map_err(|_| KeystoreError::NonCompliant)?;
 
                 collected.push((path, stamp));
             }
@@ -77,9 +131,9 @@
             .max_by_key(|(_, stamp)| stamp)
             .map(|(path, _)| path);
 
-        let path = file.ok_or(KeyStoreError::NotFound)?;
-        let content = fs.read_to_string(path).map_err(KeyStoreError::IoError)?;
-        let keys = serde_json::from_str::<Vec<Jwk>>(&content).map_err(KeyStoreError::ParseError)?;
+        let path = file.ok_or(KeystoreError::NotFound)?;
+        let content = fs.read_to_string(path).map_err(KeystoreError::FileError)?;
+        let keys = serde_json::from_str::<Vec<Jwk>>(&content).map_err(KeystoreError::ParseError)?;
 
         let filename = path
             .trim_start_matches(&format!("{}/", &dirpath))
@@ -99,16 +153,16 @@
     }
 
     /// Persists store on disk
-    fn persist(&mut self) -> Result<(), KeyStoreError> {
+    fn persist(&mut self) -> Result<(), KeystoreError> {
         self.fs
             .create_dir_all(&self.dirpath)
-            .map_err(KeyStoreError::IoError)?;
+            .map_err(KeystoreError::FileError)?;
         self.fs
             .write(
                 &self.path(),
-                &serde_json::to_string_pretty(&self.keys).map_err(KeyStoreError::SerdeError)?,
+                &serde_json::to_string_pretty(&self.keys).map_err(KeystoreError::SerdeError)?,
             )
-            .map_err(KeyStoreError::IoError)
+            .map_err(KeystoreError::FileError)
     }
 
     /// Searches keypair given public key
@@ -119,10 +173,10 @@
     /// Generates and persists an ed25519 keypair for digital signatures.
     /// Returns public Jwk for convenience.
     pub fn gen_ed25519_jwk(&mut self) -> Result<Jwk, Box<dyn Error>> {
-        let keypair = Ed25519KeyPair::new().map_err(|_| KeyStoreError::KeyPairGenerationError)?;
+        let keypair = Ed25519KeyPair::new().map_err(|_| KeystoreError::KeyPairGenerationError)?;
         let jwk: Jwk = keypair
             .try_into()
-            .map_err(|_| KeyStoreError::JwkConversionError)?;
+            .map_err(|_| KeystoreError::JwkConversionError)?;
         let pub_jwk = jwk.to_public();
 
         self.keys.push(jwk);
@@ -133,11 +187,11 @@
 
     /// Generates and persists an x25519 keypair for digital signatures.
     /// Returns public Jwk for convenience.
-    pub fn gen_x25519_jwk(&mut self) -> Result<Jwk, KeyStoreError> {
-        let keypair = X25519KeyPair::new().map_err(|_| KeyStoreError::KeyPairGenerationError)?;
+    pub fn gen_x25519_jwk(&mut self) -> Result<Jwk, KeystoreError> {
+        let keypair = X25519KeyPair::new().map_err(|_| KeystoreError::KeyPairGenerationError)?;
         let jwk: Jwk = keypair
             .try_into()
-            .map_err(|_| KeyStoreError::JwkConversionError)?;
+            .map_err(|_| KeystoreError::JwkConversionError)?;
         let pub_jwk = jwk.to_public();
 
         self.keys.push(jwk);

crates/plugins/mediator-coordination/src/util/mod.rs

@@ -4,7 +4,8 @@ use did_utils::{
     didcore::{AssertionMethod, Document, KeyAgreement, KeyFormat, VerificationMethod},
     jwk::Jwk,
 };
-use keystore::{filesystem::FileSystem, KeyStore, KeyStoreError};
+use keystore::{filesystem::FileSystem, KeyStore};
+use keystore::errors::KeystoreError;
 use serde_json::Error as SerdeError;
 use std::io;
 
@@ -43,7 +44,7 @@ pub fn read_diddoc(fs: &dyn FileSystem, storage_dirpath: &str) -> Result<Documen
 pub fn read_keystore<'a>(
     fs: &'a mut dyn FileSystem,
     storage_dirpath: &str,
-) -> Result<KeyStore<'a>, KeyStoreError> {
+) -> Result<KeyStore<'a>, KeystoreError> {
     KeyStore::latest(fs, storage_dirpath)
 }