fix: add hidden types and seed words to key manager (#4925)

Description
---
We refactor the `key_manager` crate so that hides sensitive data such as mnemonics, encryption and mac keys, etc.

Motivation and Context
---
Tackle issue #4861 and a portion of #4846.

Fixes #4861 

How Has This Been Tested?
---
Add unit tests for `SeedWords`. Also generated need wallet with visible seed words, to the user.

applications/tari_console_wallet/Cargo.toml

@@ -50,6 +50,7 @@ tonic = "0.6.2"
 tracing = "0.1.26"
 unicode-segmentation = "1.6.0"
 unicode-width = "0.1"
+zeroize = "1.3.0"
 
 [dependencies.tari_core]
 path = "../../base_layer/core"

applications/tari_console_wallet/src/init/mod.rs

@@ -401,7 +401,7 @@ pub async fn init_wallet(
     }
     if let Some(file_name) = seed_words_file_name {
         let seed_words = wallet.get_seed_words(&MnemonicLanguage::English)?.join(" ");
-        let _result = fs::write(file_name, seed_words).map_err(|e| {
+        let _result = fs::write(file_name, seed_words.reveal()).map_err(|e| {
             ExitError::new(
                 ExitCode::WalletError,
                 &format!("Problem writing seed words to file: {}", e),
@@ -549,7 +549,7 @@ fn confirm_seed_words(wallet: &mut WalletSqlite) -> Result<(), ExitError> {
     println!("WRITE THEM DOWN OR COPY THEM NOW. THIS IS YOUR ONLY CHANCE TO DO SO.");
     println!();
     println!("=========================");
-    println!("{}", seed_words.join(" "));
+    println!("{}", seed_words.join(" ").reveal());
     println!("=========================");
     println!("\x07"); // beep!
 

applications/tari_console_wallet/src/lib.rs

@@ -48,7 +48,8 @@ use tari_common::{
     configuration::bootstrap::ApplicationType,
     exit_codes::{ExitCode, ExitError},
 };
-use tari_key_manager::cipher_seed::CipherSeed;
+use tari_crypto::tari_utilities::Hidden;
+use tari_key_manager::{cipher_seed::CipherSeed, SeedWords};
 #[cfg(all(unix, feature = "libtor"))]
 use tari_libtor::tor::Tor;
 use tari_shutdown::Shutdown;
@@ -213,13 +214,15 @@ fn get_password(config: &ApplicationConfig, cli: &Cli) -> Option<SafePassword> {
 fn get_recovery_seed(boot_mode: WalletBoot, cli: &Cli) -> Result<Option<CipherSeed>, ExitError> {
     if matches!(boot_mode, WalletBoot::Recovery) {
         let seed = if cli.seed_words.is_some() {
-            let seed_words: Vec<String> = cli
-                .seed_words
-                .clone()
-                .unwrap()
-                .split_whitespace()
-                .map(|v| v.to_string())
-                .collect();
+            // need to zeroize first, to clean up memory of cli.seed_words clone
+            let seed_words: SeedWords = SeedWords::new(
+                cli.seed_words
+                    .as_ref()
+                    .unwrap()
+                    .split_whitespace()
+                    .map(|s| Hidden::hide(s.to_string()))
+                    .collect(),
+            );
             get_seed_from_seed_words(seed_words)?
         } else {
             prompt_private_key_from_seed_words()?

applications/tari_console_wallet/src/recovery.rs

@@ -27,7 +27,8 @@ use futures::FutureExt;
 use log::*;
 use rustyline::Editor;
 use tari_common::exit_codes::{ExitCode, ExitError};
-use tari_key_manager::{cipher_seed::CipherSeed, mnemonic::Mnemonic};
+use tari_crypto::tari_utilities::Hidden;
+use tari_key_manager::{cipher_seed::CipherSeed, mnemonic::Mnemonic, SeedWords};
 use tari_shutdown::Shutdown;
 use tari_utilities::hex::Hex;
 use tari_wallet::{
@@ -37,6 +38,7 @@ use tari_wallet::{
     WalletSqlite,
 };
 use tokio::sync::broadcast;
+use zeroize::Zeroizing;
 
 use crate::wallet_modes::PeerConfig;
 
@@ -51,8 +53,9 @@ pub fn prompt_private_key_from_seed_words() -> Result<CipherSeed, ExitError> {
         println!("Recovery Mode");
         println!();
         println!("Type or paste all of your seed words on one line, only separated by spaces.");
-        let input = rl.readline(">> ").map_err(|e| ExitError::new(ExitCode::IOError, e))?;
-        let seed_words: Vec<String> = input.split_whitespace().map(str::to_string).collect();
+        let input = Zeroizing::new(rl.readline(">> ").map_err(|e| ExitError::new(ExitCode::IOError, e))?);
+        let seed_words: SeedWords =
+            SeedWords::new(input.split_whitespace().map(|s| Hidden::hide(s.to_string())).collect());
 
         match CipherSeed::from_mnemonic(&seed_words, None) {
             Ok(seed) => break Ok(seed),
@@ -66,7 +69,7 @@ pub fn prompt_private_key_from_seed_words() -> Result<CipherSeed, ExitError> {
 }
 
 /// Return seed matching the seed words.
-pub fn get_seed_from_seed_words(seed_words: Vec<String>) -> Result<CipherSeed, ExitError> {
+pub fn get_seed_from_seed_words(seed_words: SeedWords) -> Result<CipherSeed, ExitError> {
     debug!(target: LOG_TARGET, "Return seed derived from the provided seed words");
     match CipherSeed::from_mnemonic(&seed_words, None) {
         Ok(seed) => Ok(seed),