Introduce a SignatoryManager service.

crates/cashu/src/nuts/nut00/mod.rs

@@ -200,6 +200,18 @@ pub enum Witness {
     HTLCWitness(HTLCWitness),
 }
 
+impl From<P2PKWitness> for Witness {
+    fn from(witness: P2PKWitness) -> Self {
+        Self::P2PKWitness(witness)
+    }
+}
+
+impl From<HTLCWitness> for Witness {
+    fn from(witness: HTLCWitness) -> Self {
+        Self::HTLCWitness(witness)
+    }
+}
+
 impl Witness {
     /// Add signatures to [`Witness`]
     pub fn add_signatures(&mut self, signatues: Vec<String>) {

crates/cashu/src/nuts/nut01/mod.rs

@@ -46,6 +46,14 @@ pub enum Error {
 #[cfg_attr(feature = "swagger", derive(utoipa::ToSchema))]
 pub struct Keys(BTreeMap<AmountStr, PublicKey>);
 
+impl Deref for Keys {
+    type Target = BTreeMap<AmountStr, PublicKey>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 impl From<MintKeys> for Keys {
     fn from(keys: MintKeys) -> Self {
         Self(

crates/cdk-common/src/error.rs

@@ -52,6 +52,14 @@ pub enum Error {
     #[error("Amount Less Invoice is not allowed")]
     AmountLessNotAllowed,
 
+    /// Internal Error - Send error
+    #[error("Internal send error: {0}")]
+    SendError(String),
+
+    /// Internal Error - Recv error
+    #[error("Internal receive error: {0}")]
+    RecvError(String),
+
     // Mint Errors
     /// Minting is disabled
     #[error("Minting is disabled")]

crates/cdk-common/src/lib.rs

@@ -13,6 +13,8 @@ pub mod error;
 pub mod lightning;
 pub mod pub_sub;
 #[cfg(feature = "mint")]
+pub mod signatory;
+#[cfg(feature = "mint")]
 pub mod subscription;
 pub mod ws;
 

crates/cdk-common/src/signatory.rs

@@ -0,0 +1,50 @@
+//! Signatory mod
+//!
+//! This module abstract all the key related operations, defining an interface for the necessary
+//! operations, to be implemented by the different signatory implementations.
+//!
+//! There is an in memory implementation, when the keys are stored in memory, in the same process,
+//! but it is isolated from the rest of the application, and they communicate through a channel with
+//! the defined API.
+use std::collections::HashMap;
+
+use bitcoin::bip32::DerivationPath;
+use cashu::{
+    BlindSignature, BlindedMessage, CurrencyUnit, Id, KeySet, KeysResponse, KeysetResponse, Proof,
+};
+
+use super::error::Error;
+
+#[async_trait::async_trait]
+/// Signatory trait
+pub trait Signatory {
+    /// Blind sign a message
+    async fn blind_sign(&self, blinded_message: BlindedMessage) -> Result<BlindSignature, Error>;
+
+    /// Verify [`Proof`] meets conditions and is signed
+    async fn verify_proof(&self, proof: Proof) -> Result<(), Error>;
+
+    /// Retrieve a keyset by id
+    async fn keyset(&self, keyset_id: Id) -> Result<Option<KeySet>, Error>;
+
+    /// Retrieve the public keys of a keyset
+    async fn keyset_pubkeys(&self, keyset_id: Id) -> Result<KeysResponse, Error>;
+
+    /// Retrieve the public keys of the active keyset for distribution to wallet
+    /// clients
+    async fn pubkeys(&self) -> Result<KeysResponse, Error>;
+
+    /// Return a list of all supported keysets
+    async fn keysets(&self) -> Result<KeysetResponse, Error>;
+
+    /// Add current keyset to inactive keysets
+    /// Generate new keyset
+    async fn rotate_keyset(
+        &self,
+        unit: CurrencyUnit,
+        derivation_path_index: u32,
+        max_order: u8,
+        input_fee_ppk: u64,
+        custom_paths: HashMap<CurrencyUnit, DerivationPath>,
+    ) -> Result<(), Error>;
+}

crates/cdk-integration-tests/src/init_regtest.rs

@@ -1,11 +1,12 @@
+use std::collections::HashMap;
 use std::env;
 use std::path::PathBuf;
 use std::sync::Arc;
 
 use anyhow::Result;
 use bip39::Mnemonic;
 use cdk::cdk_database::{self, MintDatabase};
-use cdk::mint::{FeeReserve, MintBuilder, MintMeltLimits};
+use cdk::mint::{FeeReserve, MemorySignatory, MintBuilder, MintMeltLimits};
 use cdk::nuts::{CurrencyUnit, PaymentMethod};
 use cdk_cln::Cln as CdkCln;
 use ln_regtest_rs::bitcoin_client::BitcoinClient;
@@ -134,7 +135,9 @@ where
 
     let mut mint_builder = MintBuilder::new();
 
-    mint_builder = mint_builder.with_localstore(Arc::new(database));
+    let localstore = Arc::new(database);
+
+    mint_builder = mint_builder.with_localstore(localstore.clone());
 
     mint_builder = mint_builder.add_ln_backend(
         CurrencyUnit::Sat,
@@ -145,8 +148,18 @@ where
 
     let mnemonic = Mnemonic::generate(12)?;
 
+    let signatory_manager = MemorySignatory::new(
+        localstore,
+        &mnemonic.to_seed_normalized(""),
+        mint_builder.supported_units.clone(),
+        HashMap::new(),
+    )
+    .await
+    .expect("valid signatory");
+
     mint_builder = mint_builder
         .with_name("regtest mint".to_string())
+        .with_signatory(Arc::new(signatory_manager))
         .with_mint_url(format!("http://{addr}:{port}"))
         .with_description("regtest mint".to_string())
         .with_quote_ttl(10000, 10000)

crates/cdk-integration-tests/tests/mint.rs

@@ -9,7 +9,8 @@ use bip39::Mnemonic;
 use cdk::amount::{Amount, SplitTarget};
 use cdk::cdk_database::mint_memory::MintMemoryDatabase;
 use cdk::dhke::construct_proofs;
-use cdk::mint::MintQuote;
+use cdk::mint::signatory::SignatoryManager;
+use cdk::mint::{MemorySignatory, MintQuote};
 use cdk::nuts::nut00::ProofsMethods;
 use cdk::nuts::{
     CurrencyUnit, Id, MintBolt11Request, MintInfo, NotificationPayload, Nuts, PreMintSecrets,
@@ -45,15 +46,21 @@ async fn new_mint(fee: u64) -> Mint {
 
     let quote_ttl = QuoteTTL::new(10000, 10000);
 
+    let localstore = Arc::new(MintMemoryDatabase::default());
+    let seed = mnemonic.to_seed_normalized("");
+    let signatory_manager = Arc::new(SignatoryManager::new(Arc::new(
+        MemorySignatory::new(localstore.clone(), &seed, supported_units, HashMap::new())
+            .await
+            .expect("valid signatory"),
+    )));
+
     Mint::new(
         MINT_URL,
-        &mnemonic.to_seed_normalized(""),
         mint_info,
         quote_ttl,
-        Arc::new(MintMemoryDatabase::default()),
-        HashMap::new(),
-        supported_units,
+        localstore,
         HashMap::new(),
+        signatory_manager,
     )
     .await
     .unwrap()

crates/cdk-mintd/Cargo.toml

@@ -26,6 +26,9 @@ cdk-lnbits = { path = "../cdk-lnbits", version = "0.6.0", default-features = fal
 cdk-phoenixd = { path = "../cdk-phoenixd", version = "0.6.0", default-features = false }
 cdk-lnd = { path = "../cdk-lnd", version = "0.6.0", default-features = false }
 cdk-fake-wallet = { path = "../cdk-fake-wallet", version = "0.6.0", default-features = false }
+cdk-signatory = { path = "../cdk-signatory", default-features = false, features = [
+    "grpc",
+] }
 cdk-strike = { path = "../cdk-strike", version = "0.6.0" }
 cdk-axum = { path = "../cdk-axum", version = "0.6.0", default-features = false }
 config = { version = "0.13.3", features = ["toml"] }

crates/cdk-mintd/src/bin/signatory.rs

@@ -0,0 +1,61 @@
+use std::collections::HashMap;
+use std::env;
+use std::str::FromStr;
+
+use bip39::Mnemonic;
+use cdk::nuts::CurrencyUnit;
+use cdk_mintd::cli::CLIArgs;
+use cdk_mintd::env_vars::ENV_WORK_DIR;
+use cdk_mintd::{config, work_dir};
+use cdk_signatory::proto::server::grpc_server;
+use cdk_signatory::MemorySignatory;
+use clap::Parser;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let args = CLIArgs::parse();
+    let work_dir = if let Some(work_dir) = args.work_dir {
+        tracing::info!("Using work dir from cmd arg");
+        work_dir
+    } else if let Ok(env_work_dir) = env::var(ENV_WORK_DIR) {
+        tracing::info!("Using work dir from env var");
+        env_work_dir.into()
+    } else {
+        work_dir()?
+    };
+
+    let config_file_arg = match args.config {
+        Some(c) => c,
+        None => work_dir.join("config.toml"),
+    };
+
+    let settings = if config_file_arg.exists() {
+        config::Settings::new(Some(config_file_arg))
+    } else {
+        tracing::info!("Config file does not exist. Attempting to read env vars");
+        config::Settings::default()
+    };
+
+    // This check for any settings defined in ENV VARs
+    // ENV VARS will take **priority** over those in the config
+    let mut settings = settings.from_env()?;
+    let mnemonic = Mnemonic::from_str(&settings.info.mnemonic)?;
+
+    let signatory = MemorySignatory::new(
+        settings.database.engine.clone().mint(&work_dir).await?,
+        &mnemonic.to_seed_normalized(""),
+        settings
+            .supported_units
+            .take()
+            .unwrap_or(vec![CurrencyUnit::default()])
+            .into_iter()
+            .map(|u| (u, (0, 32)))
+            .collect::<HashMap<_, _>>(),
+        HashMap::new(),
+    )
+    .await?;
+
+    grpc_server(signatory, "[::1]:50051".parse().unwrap()).await?;
+
+    Ok(())
+}

crates/cdk-mintd/src/config.rs

@@ -1,8 +1,11 @@
 use std::path::PathBuf;
+use std::sync::Arc;
 
 use cdk::nuts::{CurrencyUnit, PublicKey};
-use cdk::Amount;
+use cdk::{cdk_database, Amount};
 use cdk_axum::cache;
+use cdk_redb::MintRedbDatabase;
+use cdk_sqlite::MintSqliteDatabase;
 use config::{Config, ConfigError, File};
 use serde::{Deserialize, Serialize};
 
@@ -169,6 +172,30 @@ impl std::str::FromStr for DatabaseEngine {
     }
 }
 
+impl DatabaseEngine {
+    /// Convert the database instance into a mint database
+    pub async fn mint<P: Into<PathBuf>>(
+        self,
+        work_dir: P,
+    ) -> Result<
+        Arc<dyn cdk_database::MintDatabase<Err = cdk_database::Error> + Sync + Send + 'static>,
+        cdk_database::Error,
+    > {
+        match self {
+            DatabaseEngine::Sqlite => {
+                let sql_db_path = work_dir.into().join("cdk-mintd.sqlite");
+                let db = MintSqliteDatabase::new(&sql_db_path).await?;
+                db.migrate().await;
+                Ok(Arc::new(db))
+            }
+            DatabaseEngine::Redb => {
+                let redb_path = work_dir.into().join("cdk-mintd.redb");
+                Ok(Arc::new(MintRedbDatabase::new(&redb_path)?))
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
 pub struct Database {
     pub engine: DatabaseEngine,
@@ -187,6 +214,8 @@ pub struct Settings {
     pub lnd: Option<Lnd>,
     pub fake_wallet: Option<FakeWallet>,
     pub database: Database,
+    pub supported_units: Option<Vec<CurrencyUnit>>,
+    pub remote_signatory: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]

crates/cdk-mintd/src/env_vars.rs

@@ -72,15 +72,15 @@ pub const ENV_FAKE_WALLET_MIN_DELAY: &str = "CDK_MINTD_FAKE_WALLET_MIN_DELAY";
 pub const ENV_FAKE_WALLET_MAX_DELAY: &str = "CDK_MINTD_FAKE_WALLET_MAX_DELAY";
 
 impl Settings {
-    pub fn from_env(&mut self) -> Result<Self> {
+    pub fn from_env(mut self) -> Result<Self> {
         if let Ok(database) = env::var(DATABASE_ENV_VAR) {
             let engine = DatabaseEngine::from_str(&database).map_err(|err| anyhow!(err))?;
             self.database = Database { engine };
         }
 
-        self.info = self.info.clone().from_env();
-        self.mint_info = self.mint_info.clone().from_env();
-        self.ln = self.ln.clone().from_env();
+        self.info = self.info.from_env();
+        self.mint_info = self.mint_info.from_env();
+        self.ln = self.ln.from_env();
 
         match self.ln.ln_backend {
             LnBackend::Cln => {
@@ -104,7 +104,7 @@ impl Settings {
             LnBackend::None => bail!("Ln backend must be set"),
         }
 
-        Ok(self.clone())
+        Ok(self)
     }
 }
 

crates/cdk-mintd/src/lib.rs

@@ -2,6 +2,8 @@
 
 use std::path::PathBuf;
 
+use anyhow::anyhow;
+
 pub mod cli;
 pub mod config;
 pub mod env_vars;
@@ -22,6 +24,16 @@ fn expand_path(path: &str) -> Option<PathBuf> {
     }
 }
 
+/// Work dir
+pub fn work_dir() -> anyhow::Result<PathBuf> {
+    let home_dir = home::home_dir().ok_or(anyhow!("Unknown home dir"))?;
+    let dir = home_dir.join(".cdk-mintd");
+
+    std::fs::create_dir_all(&dir)?;
+
+    Ok(dir)
+}
+
 #[cfg(test)]
 mod test {
     use std::env::current_dir;