Make server act as "aggregator"

coordinator/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 async-trait = "0.1.81"
+derivative = "2.2.0"
 eyre = "0.6.12"
 frost-core = { version = "2.0.0-rc.0", features = ["serde"] }
 frost-rerandomized = { version = "2.0.0-rc.0", features = ["serde"] }
@@ -16,6 +17,7 @@ hex = { version = "0.4", features = ["serde"] }
 thiserror = "1.0"
 rand = "0.8"
 serde_json = "1.0"
+serdect = { version = "0.2.0" }
 itertools = "0.13.0"
 exitcode = "1.1.2"
 clap = { version = "4.5.13", features = ["derive"] }

coordinator/src/args.rs

@@ -1,6 +1,19 @@
+use std::{
+    env,
+    error::Error,
+    fs,
+    io::{BufRead, Write},
+};
+
 use clap::Parser;
+use eyre::eyre;
+
+use frost_core::{keys::PublicKeyPackage, Ciphersuite};
+use frost_rerandomized::Randomizer;
 
-#[derive(Parser, Debug, Default)]
+use crate::input::read_from_file_or_stdin;
+
+#[derive(Clone, Parser, Debug, Default)]
 #[command(author, version, about, long_about = None)]
 pub struct Args {
     #[arg(short = 'C', long, default_value = "ed25519")]
@@ -32,26 +45,31 @@ pub struct Args {
     #[arg(short = 'S', long, value_delimiter = ',')]
     pub signers: Vec<String>,
 
-    /// The number of participants. If 0, will prompt for a value.
+    /// The number of participants. If `signers` is specified, it will use the
+    /// length of `signers`. Otherwise, if 0, it will prompt for a value.
     #[arg(short = 'n', long, default_value_t = 0)]
     pub num_signers: u16,
 
     /// Public key package to use. Can be a file with a JSON-encoded
-    /// package, or "". If the file does not exist or if "" is specified,
+    /// package, or "-". If the file does not exist or if "-" is specified,
     /// then it will be read from standard input.
     #[arg(short = 'P', long, default_value = "public-key-package.json")]
     pub public_key_package: String,
 
-    /// The message to sign. Can be a file with the raw message, or "". If ""
-    /// is specified, then it will be read from standard input as a hex string.
-    #[arg(short = 'm', long, default_value = "")]
-    pub message: String,
+    /// The messages to sign. Each instance can be a file with the raw message,
+    /// "" or "-". If "" or "-" is specified, then it will be read from standard
+    /// input as a hex string. If none are passed, a single one will be read
+    /// from standard input as a hex string.
+    #[arg(short = 'm', long)]
+    pub message: Vec<String>,
 
-    /// The randomizer to use. Can be a file with the raw randomizer, empty, or
-    /// "-". If empty, a random one will be generated. If "-" is specified, then
-    /// it will be read from standard input as a hex string.
-    #[arg(short = 'r', long, default_value = "")]
-    pub randomizer: String,
+    /// The randomizers to use. Each instance can be a file with the raw
+    /// randomizer, "" or "-". If "" or "-" is specified, then it will be read
+    /// from standard input as a hex string. If none are passed, random ones
+    /// will be generated. If one or more are passed, the number should match
+    /// the `message` parameter.
+    #[arg(short = 'r', long)]
+    pub randomizer: Vec<String>,
 
     /// Where to write the generated raw bytes signature. If "-", the
     /// human-readable hex-string is printed to stdout.
@@ -66,3 +84,154 @@ pub struct Args {
     #[arg(short, long, default_value_t = 2744)]
     pub port: u16,
 }
+
+#[derive(Clone, Debug)]
+pub struct ProcessedArgs<C: Ciphersuite> {
+    pub ciphersuite: String,
+
+    /// CLI mode. If enabled, it will prompt for inputs from stdin
+    /// and print values to stdout, ignoring other flags.
+    /// If false, socket communication is enabled.
+    pub cli: bool,
+
+    /// HTTP mode. If enabled, it will use HTTP communication with a
+    /// FROST server.
+    pub http: bool,
+
+    /// The username to use in HTTP mode.
+    pub username: String,
+
+    /// The (actual) password to use in HTTP mode.
+    pub password: String,
+
+    /// The comma-separated usernames of the signers to use in HTTP mode.
+    /// If HTTP mode is enabled and this is empty, then the session ID
+    /// will be printed and will have to be shared manually.
+    pub signers: Vec<String>,
+
+    /// The number of participants.
+    pub num_signers: u16,
+
+    /// Public key package to use.
+    pub public_key_package: PublicKeyPackage<C>,
+
+    /// The messages to sign.
+    pub messages: Vec<Vec<u8>>,
+
+    /// The randomizers to use.
+    pub randomizers: Vec<Randomizer<C>>,
+
+    /// Where to write the generated raw bytes signature. If "-", the
+    /// human-readable hex-string is printed to stdout.
+    pub signature: String,
+
+    /// IP to bind to, if using online comms
+    pub ip: String,
+
+    /// Port to bind to, if using online comms
+    pub port: u16,
+}
+
+impl<C: Ciphersuite + 'static> ProcessedArgs<C> {
+    /// Create a ProcessedArgs from a Args.
+    ///
+    /// Validates inputs and reads/parses arguments.
+    pub fn new(
+        args: &Args,
+        input: &mut dyn BufRead,
+        output: &mut dyn Write,
+    ) -> Result<Self, Box<dyn Error>> {
+        let password = if args.http {
+            env::var(&args.password).map_err(|_| eyre!("The password argument must specify the name of a environment variable containing the password"))?
+        } else {
+            String::new()
+        };
+
+        let num_signers = if !args.signers.is_empty() {
+            args.signers.len() as u16
+        } else if args.num_signers == 0 {
+            writeln!(output, "The number of participants: ")?;
+
+            let mut participants = String::new();
+            input.read_line(&mut participants)?;
+            participants.trim().parse::<u16>()?
+        } else {
+            args.num_signers
+        };
+
+        let out = read_from_file_or_stdin(
+            input,
+            output,
+            "public key package",
+            &args.public_key_package,
+        )?;
+
+        let public_key_package: PublicKeyPackage<C> = serde_json::from_str(&out)?;
+
+        let messages = if args.message.is_empty() {
+            writeln!(output, "The message to be signed (hex encoded)")?;
+            let mut msg = String::new();
+            input.read_line(&mut msg)?;
+            vec![hex::decode(msg.trim())?]
+        } else {
+            args.message
+                .iter()
+                .map(|filename| {
+                    let msg = if filename == "-" || filename.is_empty() {
+                        writeln!(output, "The message to be signed (hex encoded)")?;
+                        let mut msg = String::new();
+                        input.read_line(&mut msg)?;
+                        hex::decode(msg.trim())?
+                    } else {
+                        eprintln!("Reading message from {}...", &filename);
+                        fs::read(filename)?
+                    };
+                    Ok(msg)
+                })
+                .collect::<Result<_, Box<dyn Error>>>()?
+        };
+
+        println!("Processing randomizer {:?}", args.randomizer);
+        let randomizers = if args.ciphersuite == "redpallas" {
+            if args.randomizer.is_empty() {
+                Vec::new()
+            } else {
+                args.randomizer
+                    .iter()
+                    .map(|filename| {
+                        let randomizer = if filename == "-" || filename.is_empty() {
+                            writeln!(output, "Enter the randomizer (hex string):")?;
+                            let mut randomizer = String::new();
+                            input.read_line(&mut randomizer)?;
+                            let bytes = hex::decode(randomizer.trim())?;
+                            frost_rerandomized::Randomizer::deserialize(&bytes)?
+                        } else {
+                            eprintln!("Reading randomizer from {}...", &filename);
+                            let bytes = fs::read(filename)?;
+                            frost_rerandomized::Randomizer::deserialize(&bytes)?
+                        };
+                        Ok(randomizer)
+                    })
+                    .collect::<Result<_, Box<dyn Error>>>()?
+            }
+        } else {
+            Vec::new()
+        };
+
+        Ok(ProcessedArgs {
+            ciphersuite: args.ciphersuite.clone(),
+            cli: args.cli,
+            http: args.http,
+            username: args.username.clone(),
+            password,
+            signers: args.signers.clone(),
+            num_signers,
+            public_key_package,
+            messages,
+            randomizers,
+            signature: args.signature.clone(),
+            ip: args.ip.clone(),
+            port: args.port,
+        })
+    }
+}

coordinator/src/cli.rs

@@ -3,60 +3,50 @@ use std::io::{BufRead, Write};
 use frost_rerandomized::RandomizedCiphersuite;
 
 use crate::args::Args;
+use crate::args::ProcessedArgs;
 use crate::comms::cli::CLIComms;
 use crate::comms::http::HTTPComms;
 use crate::comms::socket::SocketComms;
 use crate::comms::Comms;
 use crate::step_1::step_1;
 use crate::step_2::step_2;
-use crate::step_3::request_randomizer;
 use crate::step_3::step_3;
 
 pub async fn cli<C: RandomizedCiphersuite + 'static>(
     args: &Args,
     reader: &mut impl BufRead,
     logger: &mut impl Write,
 ) -> Result<(), Box<dyn std::error::Error>> {
+    let pargs = ProcessedArgs::<C>::new(args, reader, logger)?;
+
     writeln!(logger, "\n=== STEP 1: CHOOSE PARTICIPANTS ===\n")?;
 
     let mut comms: Box<dyn Comms<C>> = if args.cli {
         Box::new(CLIComms::new())
     } else if args.http {
-        Box::new(HTTPComms::new(args)?)
+        Box::new(HTTPComms::new(&pargs)?)
     } else {
         Box::new(SocketComms::new(args))
     };
 
-    let participants_config = step_1(args, &mut *comms, reader, logger).await?;
+    let participants_config = step_1(&pargs, &mut *comms, reader, logger).await?;
 
     writeln!(
         logger,
         "=== STEP 2: CHOOSE MESSAGE AND GENERATE COMMITMENT PACKAGE ===\n"
     )?;
 
-    let signing_package = step_2(
-        args,
-        reader,
-        logger,
-        participants_config.commitments.clone(),
-    )?;
-
-    let randomizer = if args.ciphersuite == "redpallas" {
-        Some(request_randomizer(args, reader, logger, &signing_package)?)
-    } else {
-        None
-    };
+    let signing_package = step_2(&pargs, logger, participants_config.commitments.clone())?;
 
     writeln!(logger, "=== STEP 3: BUILD GROUP SIGNATURE ===\n")?;
 
     step_3(
-        args,
+        &pargs,
         &mut *comms,
         reader,
         logger,
         participants_config,
         &signing_package,
-        randomizer,
     )
     .await?;