add Pallas and Jubjub ciphersuites and FROST support (#33)

* clippy fixes; remove old FROST code * add RedPallas ciphersuite and FROST support * organized code * simplified version * remove randomized_frost; point to frost-randomized crate * move rerandomized test to frost-rerandomized; clean up dependencies; add 'frost' feature * remove stale comment * add Jubjub support * add torsion and identity checks where needed; tests * Apply suggestions from code review Co-authored-by: Marek <mail@marek.onl> * Apply suggestions from code review Co-authored-by: Marek <mail@marek.onl> * change Jubjub serialize() to use to_bytes(); add comment to Pallas serialize() * update frost-rerandomized version * unpin nightly Rust in coverage.yaml * fix conditional hex dependency * move FROST code inside frost folder * Apply suggestions from code review Co-authored-by: Marek <mail@marek.onl> --------- Co-authored-by: Marek <mail@marek.onl> Co-authored-by: Deirdre Connolly <deirdre@zfnd.org>
2023-02-27 20:01:50 -03:00 · 2023-02-27 20:01:50 -03:00 · 08bb408846
parent 507dcdf695
commit 08bb408846
13 changed files with 1509 additions and 3 deletions
--- a/Cargo.toml
+++ b/Cargo.toml
@ -31,6 +31,7 @@ pasta_curves = { version = "0.4", default-features = false }
 rand_core = { version = "0.6", default-features = false }
 serde = { version = "1", optional = true, features = ["derive"] }
 thiserror = { version = "1.0", optional = true }
+frost-rerandomized = { git = "https://github.com/ZcashFoundation/frost.git", rev = "ffe5c57a1729c933b3ec8766ec96d2e6976a7ece", optional = true }

 [dependencies.zeroize]
 version = "1"
@ -40,12 +41,14 @@ optional = true
 [dev-dependencies]
 bincode = "1"
 criterion = "0.4"
+hex = "0.4.3"
 proptest-derive = "0.3"
 lazy_static = "1.4"
 proptest = "1.0"
 rand = "0.8"
 rand_chacha = "0.3"
 serde_json = "1.0"
+frost-rerandomized = { git = "https://github.com/ZcashFoundation/frost.git", rev = "ffe5c57a1729c933b3ec8766ec96d2e6976a7ece", features=["test-impl"] }

 # `alloc` is only used in test code
 [dev-dependencies.pasta_curves]
@ -53,9 +56,10 @@ features = ["alloc"]

 [features]
 std = ["blake2b_simd/std", "thiserror", "zeroize", "alloc",
-       "serde"] # conditional compilation for serde not complete (issue #9)
+       "serde", "frost-rerandomized"] # conditional compilation for serde not complete (issue #9)
 alloc = ["hex"]
 nightly = []
+frost = ["frost-rerandomized"]
 default = ["std"]

 [[bench]]
--- a/src/frost.rs
+++ b/src/frost.rs
@ -0,0 +1,4 @@
+//! RedDSA with FROST.
+
+pub mod redjubjub;
+pub mod redpallas;
--- a/src/frost/redjubjub.rs
+++ b/src/frost/redjubjub.rs
@ -0,0 +1,406 @@
+//! Rerandomized FROST with Jubjub curve.
+#![allow(non_snake_case)]
+#![deny(missing_docs)]
+
+use group::GroupEncoding;
+#[cfg(feature = "alloc")]
+use group::{ff::Field as FFField, ff::PrimeField};
+
+use frost_rerandomized::{
+    frost_core::{frost, Ciphersuite, Field, FieldError, Group, GroupError},
+    RandomizedParams,
+};
+
+use rand_core::{CryptoRng, RngCore};
+
+use crate::{hash::HStar, private::Sealed, sapling};
+
+/// An error type for the FROST(Jubjub, BLAKE2b-512) ciphersuite.
+pub type Error = frost_rerandomized::frost_core::Error<JubjubBlake2b512>;
+
+/// An implementation of the FROST(Jubjub, BLAKE2b-512) ciphersuite scalar field.
+#[derive(Clone, Copy)]
+pub struct JubjubScalarField;
+
+impl Field for JubjubScalarField {
+    type Scalar = jubjub::Scalar;
+
+    type Serialization = [u8; 32];
+
+    fn zero() -> Self::Scalar {
+        Self::Scalar::zero()
+    }
+
+    fn one() -> Self::Scalar {
+        Self::Scalar::one()
+    }
+
+    fn invert(scalar: &Self::Scalar) -> Result<Self::Scalar, FieldError> {
+        // [`Jubjub::Scalar`]'s Eq/PartialEq does a constant-time comparison using
+        // `ConstantTimeEq`
+        if *scalar == <Self as Field>::zero() {
+            Err(FieldError::InvalidZeroScalar)
+        } else {
+            Ok(Self::Scalar::invert(scalar).unwrap())
+        }
+    }
+
+    fn random<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar {
+        Self::Scalar::random(rng)
+    }
+
+    fn serialize(scalar: &Self::Scalar) -> Self::Serialization {
+        scalar.to_bytes()
+    }
+
+    fn little_endian_serialize(scalar: &Self::Scalar) -> Self::Serialization {
+        Self::serialize(scalar)
+    }
+
+    fn deserialize(buf: &Self::Serialization) -> Result<Self::Scalar, FieldError> {
+        match Self::Scalar::from_repr(*buf).into() {
+            Some(s) => Ok(s),
+            None => Err(FieldError::MalformedScalar),
+        }
+    }
+}
+
+/// An implementation of the FROST(Jubjub, BLAKE2b-512) ciphersuite group.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct JubjubGroup;
+
+impl Group for JubjubGroup {
+    type Field = JubjubScalarField;
+
+    type Element = jubjub::ExtendedPoint;
+
+    type Serialization = [u8; 32];
+
+    fn cofactor() -> <Self::Field as Field>::Scalar {
+        Self::Field::one()
+    }
+
+    fn identity() -> Self::Element {
+        Self::Element::identity()
+    }
+
+    fn generator() -> Self::Element {
+        sapling::SpendAuth::basepoint()
+    }
+
+    fn serialize(element: &Self::Element) -> Self::Serialization {
+        element.to_bytes()
+    }
+
+    fn deserialize(buf: &Self::Serialization) -> Result<Self::Element, GroupError> {
+        let point = Self::Element::from_bytes(buf);
+
+        match Option::<Self::Element>::from(point) {
+            Some(point) => {
+                if point == Self::identity() {
+                    Err(GroupError::InvalidIdentityElement)
+                } else if point.is_torsion_free().into() {
+                    Ok(point)
+                } else {
+                    Err(GroupError::InvalidNonPrimeOrderElement)
+                }
+            }
+            None => Err(GroupError::MalformedElement),
+        }
+    }
+}
+
+/// An implementation of the FROST(Jubjub, BLAKE2b-512) ciphersuite.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct JubjubBlake2b512;
+
+impl Ciphersuite for JubjubBlake2b512 {
+    type Group = JubjubGroup;
+
+    type HashOutput = [u8; 64];
+
+    type SignatureSerialization = [u8; 64];
+
+    /// H1 for FROST(Jubjub, BLAKE2b-512)
+    fn H1(m: &[u8]) -> <<Self::Group as Group>::Field as Field>::Scalar {
+        HStar::<sapling::SpendAuth>::new(b"FROST_RedJubjubR")
+            .update(m)
+            .finalize()
+    }
+
+    /// H2 for FROST(Jubjub, BLAKE2b-512)
+    fn H2(m: &[u8]) -> <<Self::Group as Group>::Field as Field>::Scalar {
+        HStar::<sapling::SpendAuth>::default().update(m).finalize()
+    }
+
+    /// H3 for FROST(Jubjub, BLAKE2b-512)
+    fn H3(m: &[u8]) -> <<Self::Group as Group>::Field as Field>::Scalar {
+        HStar::<sapling::SpendAuth>::new(b"FROST_RedJubjubN")
+            .update(m)
+            .finalize()
+    }
+
+    /// H4 for FROST(Jubjub, BLAKE2b-512)
+    fn H4(m: &[u8]) -> Self::HashOutput {
+        let mut state = blake2b_simd::Params::new()
+            .hash_length(64)
+            .personal(b"FROST_RedJubjubM")
+            .to_state();
+        *state.update(m).finalize().as_array()
+    }
+
+    /// H5 for FROST(Jubjub, BLAKE2b-512)
+    fn H5(m: &[u8]) -> Self::HashOutput {
+        let mut state = blake2b_simd::Params::new()
+            .hash_length(64)
+            .personal(b"FROST_RedJubjubC")
+            .to_state();
+        *state.update(m).finalize().as_array()
+    }
+
+    /// HDKG for FROST(Jubjub, BLAKE2b-512)
+    fn HDKG(m: &[u8]) -> Option<<<Self::Group as Group>::Field as Field>::Scalar> {
+        Some(
+            HStar::<sapling::SpendAuth>::new(b"FROST_RedJubjubD")
+                .update(m)
+                .finalize(),
+        )
+    }
+}
+
+// Shorthand alias for the ciphersuite
+type J = JubjubBlake2b512;
+
+/// A FROST(Jubjub, BLAKE2b-512) participant identifier.
+pub type Identifier = frost::Identifier<J>;
+
+/// FROST(Jubjub, BLAKE2b-512) keys, key generation, key shares.
+pub mod keys {
+    use alloc::vec::Vec;
+
+    use super::*;
+
+    /// Allows all participants' keys to be generated using a central, trusted
+    /// dealer.
+    pub fn keygen_with_dealer<RNG: RngCore + CryptoRng>(
+        max_signers: u16,
+        min_signers: u16,
+        mut rng: RNG,
+    ) -> Result<(Vec<SecretShare>, PublicKeyPackage), Error> {
+        frost::keys::keygen_with_dealer(max_signers, min_signers, &mut rng)
+    }
+
+    /// Secret and public key material generated by a dealer performing
+    /// [`keygen_with_dealer`].
+    ///
+    /// # Security
+    ///
+    /// To derive a FROST(Jubjub, BLAKE2b-512) keypair, the receiver of the [`SecretShare`] *must* call
+    /// .into(), which under the hood also performs validation.
+    pub type SecretShare = frost::keys::SecretShare<J>;
+
+    /// A FROST(Jubjub, BLAKE2b-512) keypair, which can be generated either by a trusted dealer or using
+    /// a DKG.
+    ///
+    /// When using a central dealer, [`SecretShare`]s are distributed to
+    /// participants, who then perform verification, before deriving
+    /// [`KeyPackage`]s, which they store to later use during signing.
+    pub type KeyPackage = frost::keys::KeyPackage<J>;
+
+    /// Public data that contains all the signers' public keys as well as the
+    /// group public key.
+    ///
+    /// Used for verification purposes before publishing a signature.
+    pub type PublicKeyPackage = frost::keys::PublicKeyPackage<J>;
+
+    pub mod dkg {
+        #![doc = include_str!("./redjubjub/dkg.md")]
+        use super::*;
+
+        /// The secret package that must be kept in memory by the participant
+        /// between the first and second parts of the DKG protocol (round 1).
+        ///
+        /// # Security
+        ///
+        /// This package MUST NOT be sent to other participants!
+        pub type Round1SecretPackage = frost::keys::dkg::Round1SecretPackage<J>;
+
+        /// The package that must be broadcast by each participant to all other participants
+        /// between the first and second parts of the DKG protocol (round 1).
+        pub type Round1Package = frost::keys::dkg::Round1Package<J>;
+
+        /// The secret package that must be kept in memory by the participant
+        /// between the second and third parts of the DKG protocol (round 2).
+        ///
+        /// # Security
+        ///
+        /// This package MUST NOT be sent to other participants!
+        pub type Round2SecretPackage = frost::keys::dkg::Round2SecretPackage<J>;
+
+        /// A package that must be sent by each participant to some other participants
+        /// in Round 2 of the DKG protocol. Note that there is one specific package
+        /// for each specific recipient, in contrast to Round 1.
+        ///
+        /// # Security
+        ///
+        /// The package must be sent on an *confidential* and *authenticated* channel.
+        pub type Round2Package = frost::keys::dkg::Round2Package<J>;
+
+        /// Performs the first part of the distributed key generation protocol
+        /// for the given participant.
+        ///
+        /// It returns the [`Round1SecretPackage`] that must be kept in memory
+        /// by the participant for the other steps, and the [`Round1Package`] that
+        /// must be sent to other participants.
+        pub fn keygen_part1<R: RngCore + CryptoRng>(
+            identifier: Identifier,
+            max_signers: u16,
+            min_signers: u16,
+            mut rng: R,
+        ) -> Result<(Round1SecretPackage, Round1Package), Error> {
+            frost::keys::dkg::keygen_part1(identifier, max_signers, min_signers, &mut rng)
+        }
+
+        /// Performs the second part of the distributed key generation protocol
+        /// for the participant holding the given [`Round1SecretPackage`],
+        /// given the received [`Round1Package`]s received from the other participants.
+        ///
+        /// It returns the [`Round2SecretPackage`] that must be kept in memory
+        /// by the participant for the final step, and the [`Round2Package`]s that
+        /// must be sent to other participants.
+        pub fn keygen_part2(
+            secret_package: Round1SecretPackage,
+            round1_packages: &[Round1Package],
+        ) -> Result<(Round2SecretPackage, Vec<Round2Package>), Error> {
+            frost::keys::dkg::keygen_part2(secret_package, round1_packages)
+        }
+
+        /// Performs the third and final part of the distributed key generation protocol
+        /// for the participant holding the given [`Round2SecretPackage`],
+        /// given the received [`Round1Package`]s and [`Round2Package`]s received from
+        /// the other participants.
+        ///
+        /// It returns the [`KeyPackage`] that has the long-lived key share for the
+        /// participant, and the [`PublicKeyPackage`]s that has public information
+        /// about all participants; both of which are required to compute FROST
+        /// signatures.
+        pub fn keygen_part3(
+            round2_secret_package: &Round2SecretPackage,
+            round1_packages: &[Round1Package],
+            round2_packages: &[Round2Package],
+        ) -> Result<(KeyPackage, PublicKeyPackage), Error> {
+            frost::keys::dkg::keygen_part3(round2_secret_package, round1_packages, round2_packages)
+        }
+    }
+}
+
+/// FROST(Jubjub, BLAKE2b-512) Round 1 functionality and types.
+pub mod round1 {
+    use frost_rerandomized::frost_core::frost::keys::SigningShare;
+
+    use super::*;
+    /// Comprised of FROST(Jubjub, BLAKE2b-512) hiding and binding nonces.
+    ///
+    /// Note that [`SigningNonces`] must be used *only once* for a signing
+    /// operation; re-using nonces will result in leakage of a signer's long-lived
+    /// signing key.
+    pub type SigningNonces = frost::round1::SigningNonces<J>;
+
+    /// Published by each participant in the first round of the signing protocol.
+    ///
+    /// This step can be batched if desired by the implementation. Each
+    /// SigningCommitment can be used for exactly *one* signature.
+    pub type SigningCommitments = frost::round1::SigningCommitments<J>;
+
+    /// Performed once by each participant selected for the signing operation.
+    ///
+    /// Generates the signing nonces and commitments to be used in the signing
+    /// operation.
+    pub fn commit<RNG>(
+        participant_identifier: frost::Identifier<J>,
+        secret: &SigningShare<J>,
+        rng: &mut RNG,
+    ) -> (SigningNonces, SigningCommitments)
+    where
+        RNG: CryptoRng + RngCore,
+    {
+        frost::round1::commit::<J, RNG>(participant_identifier, secret, rng)
+    }
+}
+
+/// Generated by the coordinator of the signing operation and distributed to
+/// each signing party.
+pub type SigningPackage = frost::SigningPackage<J>;
+
+/// FROST(Jubjub, BLAKE2b-512) Round 2 functionality and types, for signature share generation.
+pub mod round2 {
+    use super::*;
+
+    /// A FROST(Jubjub, BLAKE2b-512) participant's signature share, which the Coordinator will aggregate with all other signer's
+    /// shares into the joint signature.
+    pub type SignatureShare = frost::round2::SignatureShare<J>;
+
+    /// Generated by the coordinator of the signing operation and distributed to
+    /// each signing party
+    pub type SigningPackage = frost::SigningPackage<J>;
+
+    /// Performed once by each participant selected for the signing operation.
+    ///
+    /// Receives the message to be signed and a set of signing commitments and a set
+    /// of randomizing commitments to be used in that signing operation, including
+    /// that for this participant.
+    ///
+    /// Assumes the participant has already determined which nonce corresponds with
+    /// the commitment that was assigned by the coordinator in the SigningPackage.
+    pub fn sign(
+        signing_package: &SigningPackage,
+        signer_nonces: &round1::SigningNonces,
+        key_package: &keys::KeyPackage,
+        randomizer_point: &<<J as Ciphersuite>::Group as Group>::Element,
+    ) -> Result<SignatureShare, Error> {
+        frost_rerandomized::sign(
+            signing_package,
+            signer_nonces,
+            key_package,
+            randomizer_point,
+        )
+    }
+}
+
+/// A Schnorr signature on FROST(Jubjub, BLAKE2b-512).
+pub type Signature = frost_rerandomized::frost_core::Signature<J>;
+
+/// Verifies each FROST(Jubjub, BLAKE2b-512) participant's signature share, and if all are valid,
+/// aggregates the shares into a signature to publish.
+///
+/// Resulting signature is compatible with verification of a plain Schnorr
+/// signature.
+///
+/// This operation is performed by a coordinator that can communicate with all
+/// the signing participants before publishing the final signature. The
+/// coordinator can be one of the participants or a semi-trusted third party
+/// (who is trusted to not perform denial of service attacks, but does not learn
+/// any secret information). Note that because the coordinator is trusted to
+/// report misbehaving parties in order to avoid publishing an invalid
+/// signature, if the coordinator themselves is a signer and misbehaves, they
+/// can avoid that step. However, at worst, this results in a denial of
+/// service attack due to publishing an invalid signature.
+pub fn aggregate(
+    signing_package: &round2::SigningPackage,
+    signature_shares: &[round2::SignatureShare],
+    pubkeys: &keys::PublicKeyPackage,
+    randomized_params: &RandomizedParams<J>,
+) -> Result<Signature, Error> {
+    frost_rerandomized::aggregate(
+        signing_package,
+        signature_shares,
+        pubkeys,
+        randomized_params,
+    )
+}
+
+/// A signing key for a Schnorr signature on FROST(Jubjub, BLAKE2b-512).
+pub type SigningKey = frost_rerandomized::frost_core::SigningKey<J>;
+
+/// A valid verifying key for Schnorr signatures on FROST(Jubjub, BLAKE2b-512).
+pub type VerifyingKey = frost_rerandomized::frost_core::VerifyingKey<J>;
--- a/src/frost/redjubjub/README.md
+++ b/src/frost/redjubjub/README.md
@ -0,0 +1,98 @@
+An implementation of Schnorr signatures on the Jubjub curve for both single and threshold numbers
+of signers (FROST).
+
+## Example: key generation with trusted dealer and FROST signing
+
+Creating a key with a trusted dealer and splitting into shares; then signing a message
+and aggregating the signature. Note that the example just simulates a distributed
+scenario in a single thread and it abstracts away any communication between peers.
+
+
+```rust
+use reddsa::frost::redjubjub as frost;
+use rand::thread_rng;
+use std::collections::HashMap;
+
+let mut rng = thread_rng();
+let max_signers = 5;
+let min_signers = 3;
+let (shares, pubkeys) = frost::keys::keygen_with_dealer(max_signers, min_signers, &mut rng)?;
+
+// Verifies the secret shares from the dealer and stores them in a HashMap.
+// In practice, each KeyPackage must be sent to its respective participant
+// through a confidential and authenticated channel.
+let key_packages: HashMap<_, _> = shares
+    .into_iter()
+    .map(|share| Ok((share.identifier, frost::keys::KeyPackage::try_from(share)?)))
+    .collect::<Result<_, _>>()?;
+
+let mut nonces = HashMap::new();
+let mut commitments = HashMap::new();
+
+////////////////////////////////////////////////////////////////////////////
+// Round 1: generating nonces and signing commitments for each participant
+////////////////////////////////////////////////////////////////////////////
+
+// In practice, each iteration of this loop will be executed by its respective participant.
+for participant_index in 1..(min_signers as u16 + 1) {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    // Generate one (1) nonce and one SigningCommitments instance for each
+    // participant, up to _threshold_.
+    let (nonce, commitment) = frost::round1::commit(
+        participant_identifier,
+        key_packages[&participant_identifier].secret_share(),
+        &mut rng,
+    );
+    // In practice, the nonces and commitments must be sent to the coordinator
+    // (or to every other participant if there is no coordinator) using
+    // an authenticated channel.
+    nonces.insert(participant_identifier, nonce);
+    commitments.insert(participant_identifier, commitment);
+}
+
+// This is what the signature aggregator / coordinator needs to do:
+// - decide what message to sign
+// - take one (unused) commitment per signing participant
+let mut signature_shares = Vec::new();
+let message = "message to sign".as_bytes();
+let comms = commitments.clone().into_values().collect();
+// In practice, the SigningPackage must be sent to all participants
+// involved in the current signing (at least min_signers participants),
+// using an authenticated channel (and confidential if the message is secret).
+let signing_package = frost::SigningPackage::new(comms, message.to_vec());
+
+////////////////////////////////////////////////////////////////////////////
+// Round 2: each participant generates their signature share
+////////////////////////////////////////////////////////////////////////////
+
+// In practice, each iteration of this loop will be executed by its respective participant.
+for participant_identifier in nonces.keys() {
+    let key_package = &key_packages[participant_identifier];
+
+    let nonces_to_use = &nonces[participant_identifier];
+
+    // Each participant generates their signature share.
+    let signature_share = frost::round2::sign(&signing_package, nonces_to_use, key_package)?;
+
+    // In practice, the signature share must be sent to the Coordinator
+    // using an authenticated channel.
+    signature_shares.push(signature_share);
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Aggregation: collects the signing shares from all participants,
+// generates the final signature.
+////////////////////////////////////////////////////////////////////////////
+
+// Aggregate (also verifies the signature shares)
+let group_signature = frost::aggregate(&signing_package, &signature_shares[..], &pubkeys)?;
+
+// Check that the threshold signature can be verified by the group public
+// key (the verification key).
+assert!(pubkeys
+    .group_public
+    .verify(message, &group_signature)
+    .is_ok());
+
+# Ok::<(), frost::Error>(())
+```
--- a/src/frost/redjubjub/dkg.md
+++ b/src/frost/redjubjub/dkg.md
@ -0,0 +1,157 @@
+# Distributed Key Generation (DKG)
+
+The DKG module supports generating FROST key shares in a distributed manner,
+without a trusted dealer.
+
+Before starting, each participant needs a unique identifier, which can be built from
+a `u16`. The process in which these identifiers are allocated is up to the application.
+
+The distributed key generation process has 3 parts, with 2 communication rounds
+between them, in which each participant needs to send a "package" to every other
+participant. In the first round, each participant sends the same package
+(a [`Round1Package`]) to every other. In the second round, each receiver gets
+their own package (a [`Round2Package`]).
+
+Between part 1 and 2, each participant needs to hold onto a [`Round1SecretPackage`]
+that MUST be kept secret. Between part 2 and 3, each participant needs to hold
+onto a [`Round2SecretPackage`].
+
+After the third part, each participant will get a [`KeyPackage`] with their
+long-term secret share that must be kept secret, and a [`PublicKeyPackage`]
+that is public (and will be the same between all participants). With those
+they can proceed to sign messages with FROST.
+
+
+## Example
+
+```rust
+use rand::thread_rng;
+use std::collections::HashMap;
+
+use reddsa::frost::redjubjub as frost;
+
+let mut rng = thread_rng();
+
+////////////////////////////////////////////////////////////////////////////
+// Key generation, Round 1
+////////////////////////////////////////////////////////////////////////////
+
+let max_signers = 5;
+let min_signers = 3;
+
+// Keep track of each participant's round 1 secret package.
+// In practice each participant will keep its copy; no one
+// will have all the participant's packages.
+let mut round1_secret_packages = HashMap::new();
+
+// Keep track of all round 1 packages sent to the given participant.
+// This is used to simulate the broadcast; in practice the packages
+// will be sent through some communication channel.
+let mut received_round1_packages = HashMap::new();
+
+// For each participant, perform the first part of the DKG protocol.
+// In practice, each participant will perform this on their own environments.
+for participant_index in 1..=max_signers {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    let (secret_package, round1_package) = frost::keys::dkg::keygen_part1(
+        participant_identifier,
+        max_signers,
+        min_signers,
+        &mut rng,
+    )?;
+
+    // Store the participant's secret package for later use.
+    // In practice each participant will store it in their own environment.
+    round1_secret_packages.insert(participant_identifier, secret_package);
+
+    // "Send" the round 1 package to all other participants. In this
+    // test this is simulated using a HashMap; in practice this will be
+    // sent through some communication channel.
+    for receiver_participant_index in 1..=max_signers {
+        if receiver_participant_index == participant_index {
+            continue;
+        }
+        let receiver_participant_identifier: frost::Identifier = receiver_participant_index
+            .try_into()
+            .expect("should be nonzero");
+        received_round1_packages
+            .entry(receiver_participant_identifier)
+            .or_insert_with(Vec::new)
+            .push(round1_package.clone());
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Key generation, Round 2
+////////////////////////////////////////////////////////////////////////////
+
+// Keep track of each participant's round 2 secret package.
+// In practice each participant will keep its copy; no one
+// will have all the participant's packages.
+let mut round2_secret_packages = HashMap::new();
+
+// Keep track of all round 2 packages sent to the given participant.
+// This is used to simulate the broadcast; in practice the packages
+// will be sent through some communication channel.
+let mut received_round2_packages = HashMap::new();
+
+// For each participant, perform the second part of the DKG protocol.
+// In practice, each participant will perform this on their own environments.
+for participant_index in 1..=max_signers {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    let (round2_secret_package, round2_packages) = frost::keys::dkg::keygen_part2(
+        round1_secret_packages
+            .remove(&participant_identifier)
+            .unwrap(),
+        &received_round1_packages[&participant_identifier],
+    )?;
+
+    // Store the participant's secret package for later use.
+    // In practice each participant will store it in their own environment.
+    round2_secret_packages.insert(participant_identifier, round2_secret_package);
+
+    // "Send" the round 2 package to all other participants. In this
+    // test this is simulated using a HashMap; in practice this will be
+    // sent through some communication channel.
+    // Note that, in contrast to the previous part, here each other participant
+    // gets its own specific package.
+    for round2_package in round2_packages {
+        received_round2_packages
+            .entry(round2_package.receiver_identifier)
+            .or_insert_with(Vec::new)
+            .push(round2_package);
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Key generation, final computation
+////////////////////////////////////////////////////////////////////////////
+
+// Keep track of each participant's long-lived key package.
+// In practice each participant will keep its copy; no one
+// will have all the participant's packages.
+let mut key_packages = HashMap::new();
+
+// Keep track of each participant's public key package.
+// In practice, if there is a Coordinator, only they need to store the set.
+// If there is not, then all candidates must store their own sets.
+// All participants will have the same exact public key package.
+let mut pubkey_packages = HashMap::new();
+
+// For each participant, perform the third part of the DKG protocol.
+// In practice, each participant will perform this on their own environments.
+for participant_index in 1..=max_signers {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    let (key_package, pubkey_package_for_participant) = frost::keys::dkg::keygen_part3(
+        &round2_secret_packages[&participant_identifier],
+        &received_round1_packages[&participant_identifier],
+        &received_round2_packages[&participant_identifier],
+    )?;
+    key_packages.insert(participant_identifier, key_package);
+    pubkey_packages.insert(participant_identifier, pubkey_package_for_participant);
+}
+
+// With its own key package and the pubkey package, each participant can now proceed
+// to sign with FROST.
+# Ok::<(), frost::Error>(())
+```
--- a/src/frost/redpallas.rs
+++ b/src/frost/redpallas.rs
@ -0,0 +1,408 @@
+//! Rerandomized FROST with Pallas curve.
+#![allow(non_snake_case)]
+#![deny(missing_docs)]
+
+use group::GroupEncoding;
+#[cfg(feature = "alloc")]
+use group::{ff::Field as FFField, ff::PrimeField, Group as FFGroup};
+use pasta_curves::pallas;
+
+use frost_rerandomized::{
+    frost_core::{frost, Ciphersuite, Field, FieldError, Group, GroupError},
+    RandomizedParams,
+};
+
+use rand_core::{CryptoRng, RngCore};
+
+use crate::{hash::HStar, orchard, private::Sealed};
+
+/// An error type for the FROST(Pallas, BLAKE2b-512) ciphersuite.
+pub type Error = frost_rerandomized::frost_core::Error<PallasBlake2b512>;
+
+/// An implementation of the FROST(Pallas, BLAKE2b-512) ciphersuite scalar field.
+#[derive(Clone, Copy)]
+pub struct PallasScalarField;
+
+impl Field for PallasScalarField {
+    type Scalar = pallas::Scalar;
+
+    type Serialization = [u8; 32];
+
+    fn zero() -> Self::Scalar {
+        Self::Scalar::zero()
+    }
+
+    fn one() -> Self::Scalar {
+        Self::Scalar::one()
+    }
+
+    fn invert(scalar: &Self::Scalar) -> Result<Self::Scalar, FieldError> {
+        // [`pallas::Scalar`]'s Eq/PartialEq does a constant-time comparison using
+        // `ConstantTimeEq`
+        if *scalar == <Self as Field>::zero() {
+            Err(FieldError::InvalidZeroScalar)
+        } else {
+            Ok(Self::Scalar::invert(scalar).unwrap())
+        }
+    }
+
+    fn random<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar {
+        Self::Scalar::random(rng)
+    }
+
+    fn serialize(scalar: &Self::Scalar) -> Self::Serialization {
+        // to_repr() endianess is implementation-specific, but this is OK since
+        // it is specific to [`pallas::Scalar`] which uses little-endian and that
+        // is what we want.
+        scalar.to_repr()
+    }
+
+    fn little_endian_serialize(scalar: &Self::Scalar) -> Self::Serialization {
+        Self::serialize(scalar)
+    }
+
+    fn deserialize(buf: &Self::Serialization) -> Result<Self::Scalar, FieldError> {
+        match pallas::Scalar::from_repr(*buf).into() {
+            Some(s) => Ok(s),
+            None => Err(FieldError::MalformedScalar),
+        }
+    }
+}
+
+/// An implementation of the FROST(Pallas, BLAKE2b-512) ciphersuite group.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct PallasGroup;
+
+impl Group for PallasGroup {
+    type Field = PallasScalarField;
+
+    type Element = pallas::Point;
+
+    type Serialization = [u8; 32];
+
+    fn cofactor() -> <Self::Field as Field>::Scalar {
+        Self::Field::one()
+    }
+
+    fn identity() -> Self::Element {
+        Self::Element::identity()
+    }
+
+    fn generator() -> Self::Element {
+        orchard::SpendAuth::basepoint()
+    }
+
+    fn serialize(element: &Self::Element) -> Self::Serialization {
+        element.to_bytes()
+    }
+
+    fn deserialize(buf: &Self::Serialization) -> Result<Self::Element, GroupError> {
+        let point = Self::Element::from_bytes(buf);
+
+        match Option::<Self::Element>::from(point) {
+            Some(point) => {
+                if point == Self::identity() {
+                    Err(GroupError::InvalidIdentityElement)
+                } else {
+                    Ok(point)
+                }
+            }
+            None => Err(GroupError::MalformedElement),
+        }
+    }
+}
+
+/// An implementation of the FROST(Pallas, BLAKE2b-512) ciphersuite.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct PallasBlake2b512;
+
+impl Ciphersuite for PallasBlake2b512 {
+    type Group = PallasGroup;
+
+    type HashOutput = [u8; 64];
+
+    type SignatureSerialization = [u8; 64];
+
+    /// H1 for FROST(Pallas, BLAKE2b-512)
+    fn H1(m: &[u8]) -> <<Self::Group as Group>::Field as Field>::Scalar {
+        HStar::<orchard::SpendAuth>::new(b"FROST_RedPallasR")
+            .update(m)
+            .finalize()
+    }
+
+    /// H2 for FROST(Pallas, BLAKE2b-512)
+    fn H2(m: &[u8]) -> <<Self::Group as Group>::Field as Field>::Scalar {
+        HStar::<orchard::SpendAuth>::default().update(m).finalize()
+    }
+
+    /// H3 for FROST(Pallas, BLAKE2b-512)
+    fn H3(m: &[u8]) -> <<Self::Group as Group>::Field as Field>::Scalar {
+        HStar::<orchard::SpendAuth>::new(b"FROST_RedPallasN")
+            .update(m)
+            .finalize()
+    }
+
+    /// H4 for FROST(Pallas, BLAKE2b-512)
+    fn H4(m: &[u8]) -> Self::HashOutput {
+        let mut state = blake2b_simd::Params::new()
+            .hash_length(64)
+            .personal(b"FROST_RedPallasM")
+            .to_state();
+        *state.update(m).finalize().as_array()
+    }
+
+    /// H5 for FROST(Pallas, BLAKE2b-512)
+    fn H5(m: &[u8]) -> Self::HashOutput {
+        let mut state = blake2b_simd::Params::new()
+            .hash_length(64)
+            .personal(b"FROST_RedPallasC")
+            .to_state();
+        *state.update(m).finalize().as_array()
+    }
+
+    /// HDKG for FROST(Pallas, BLAKE2b-512)
+    fn HDKG(m: &[u8]) -> Option<<<Self::Group as Group>::Field as Field>::Scalar> {
+        Some(
+            HStar::<orchard::SpendAuth>::new(b"FROST_RedPallasD")
+                .update(m)
+                .finalize(),
+        )
+    }
+}
+
+// Shorthand alias for the ciphersuite
+type P = PallasBlake2b512;
+
+/// A FROST(Pallas, BLAKE2b-512) participant identifier.
+pub type Identifier = frost::Identifier<P>;
+
+/// FROST(Pallas, BLAKE2b-512) keys, key generation, key shares.
+pub mod keys {
+    use alloc::vec::Vec;
+
+    use super::*;
+
+    /// Allows all participants' keys to be generated using a central, trusted
+    /// dealer.
+    pub fn keygen_with_dealer<RNG: RngCore + CryptoRng>(
+        max_signers: u16,
+        min_signers: u16,
+        mut rng: RNG,
+    ) -> Result<(Vec<SecretShare>, PublicKeyPackage), Error> {
+        frost::keys::keygen_with_dealer(max_signers, min_signers, &mut rng)
+    }
+
+    /// Secret and public key material generated by a dealer performing
+    /// [`keygen_with_dealer`].
+    ///
+    /// # Security
+    ///
+    /// To derive a FROST(Pallas, BLAKE2b-512) keypair, the receiver of the [`SecretShare`] *must* call
+    /// .into(), which under the hood also performs validation.
+    pub type SecretShare = frost::keys::SecretShare<P>;
+
+    /// A FROST(Pallas, BLAKE2b-512) keypair, which can be generated either by a trusted dealer or using
+    /// a DKG.
+    ///
+    /// When using a central dealer, [`SecretShare`]s are distributed to
+    /// participants, who then perform verification, before deriving
+    /// [`KeyPackage`]s, which they store to later use during signing.
+    pub type KeyPackage = frost::keys::KeyPackage<P>;
+
+    /// Public data that contains all the signers' public keys as well as the
+    /// group public key.
+    ///
+    /// Used for verification purposes before publishing a signature.
+    pub type PublicKeyPackage = frost::keys::PublicKeyPackage<P>;
+
+    pub mod dkg {
+        #![doc = include_str!("./redpallas/dkg.md")]
+        use super::*;
+
+        /// The secret package that must be kept in memory by the participant
+        /// between the first and second parts of the DKG protocol (round 1).
+        ///
+        /// # Security
+        ///
+        /// This package MUST NOT be sent to other participants!
+        pub type Round1SecretPackage = frost::keys::dkg::Round1SecretPackage<P>;
+
+        /// The package that must be broadcast by each participant to all other participants
+        /// between the first and second parts of the DKG protocol (round 1).
+        pub type Round1Package = frost::keys::dkg::Round1Package<P>;
+
+        /// The secret package that must be kept in memory by the participant
+        /// between the second and third parts of the DKG protocol (round 2).
+        ///
+        /// # Security
+        ///
+        /// This package MUST NOT be sent to other participants!
+        pub type Round2SecretPackage = frost::keys::dkg::Round2SecretPackage<P>;
+
+        /// A package that must be sent by each participant to some other participants
+        /// in Round 2 of the DKG protocol. Note that there is one specific package
+        /// for each specific recipient, in contrast to Round 1.
+        ///
+        /// # Security
+        ///
+        /// The package must be sent on an *confidential* and *authenticated* channel.
+        pub type Round2Package = frost::keys::dkg::Round2Package<P>;
+
+        /// Performs the first part of the distributed key generation protocol
+        /// for the given participant.
+        ///
+        /// It returns the [`Round1SecretPackage`] that must be kept in memory
+        /// by the participant for the other steps, and the [`Round1Package`] that
+        /// must be sent to other participants.
+        pub fn keygen_part1<R: RngCore + CryptoRng>(
+            identifier: Identifier,
+            max_signers: u16,
+            min_signers: u16,
+            mut rng: R,
+        ) -> Result<(Round1SecretPackage, Round1Package), Error> {
+            frost::keys::dkg::keygen_part1(identifier, max_signers, min_signers, &mut rng)
+        }
+
+        /// Performs the second part of the distributed key generation protocol
+        /// for the participant holding the given [`Round1SecretPackage`],
+        /// given the received [`Round1Package`]s received from the other participants.
+        ///
+        /// It returns the [`Round2SecretPackage`] that must be kept in memory
+        /// by the participant for the final step, and the [`Round2Package`]s that
+        /// must be sent to other participants.
+        pub fn keygen_part2(
+            secret_package: Round1SecretPackage,
+            round1_packages: &[Round1Package],
+        ) -> Result<(Round2SecretPackage, Vec<Round2Package>), Error> {
+            frost::keys::dkg::keygen_part2(secret_package, round1_packages)
+        }
+
+        /// Performs the third and final part of the distributed key generation protocol
+        /// for the participant holding the given [`Round2SecretPackage`],
+        /// given the received [`Round1Package`]s and [`Round2Package`]s received from
+        /// the other participants.
+        ///
+        /// It returns the [`KeyPackage`] that has the long-lived key share for the
+        /// participant, and the [`PublicKeyPackage`]s that has public information
+        /// about all participants; both of which are required to compute FROST
+        /// signatures.
+        pub fn keygen_part3(
+            round2_secret_package: &Round2SecretPackage,
+            round1_packages: &[Round1Package],
+            round2_packages: &[Round2Package],
+        ) -> Result<(KeyPackage, PublicKeyPackage), Error> {
+            frost::keys::dkg::keygen_part3(round2_secret_package, round1_packages, round2_packages)
+        }
+    }
+}
+
+/// FROST(Pallas, BLAKE2b-512) Round 1 functionality and types.
+pub mod round1 {
+    use frost_rerandomized::frost_core::frost::keys::SigningShare;
+
+    use super::*;
+    /// Comprised of FROST(Pallas, BLAKE2b-512) hiding and binding nonces.
+    ///
+    /// Note that [`SigningNonces`] must be used *only once* for a signing
+    /// operation; re-using nonces will result in leakage of a signer's long-lived
+    /// signing key.
+    pub type SigningNonces = frost::round1::SigningNonces<P>;
+
+    /// Published by each participant in the first round of the signing protocol.
+    ///
+    /// This step can be batched if desired by the implementation. Each
+    /// SigningCommitment can be used for exactly *one* signature.
+    pub type SigningCommitments = frost::round1::SigningCommitments<P>;
+
+    /// Performed once by each participant selected for the signing operation.
+    ///
+    /// Generates the signing nonces and commitments to be used in the signing
+    /// operation.
+    pub fn commit<RNG>(
+        participant_identifier: frost::Identifier<P>,
+        secret: &SigningShare<P>,
+        rng: &mut RNG,
+    ) -> (SigningNonces, SigningCommitments)
+    where
+        RNG: CryptoRng + RngCore,
+    {
+        frost::round1::commit::<P, RNG>(participant_identifier, secret, rng)
+    }
+}
+
+/// Generated by the coordinator of the signing operation and distributed to
+/// each signing party.
+pub type SigningPackage = frost::SigningPackage<P>;
+
+/// FROST(Pallas, BLAKE2b-512) Round 2 functionality and types, for signature share generation.
+pub mod round2 {
+    use super::*;
+
+    /// A FROST(Pallas, BLAKE2b-512) participant's signature share, which the Coordinator will aggregate with all other signer's
+    /// shares into the joint signature.
+    pub type SignatureShare = frost::round2::SignatureShare<P>;
+
+    /// Generated by the coordinator of the signing operation and distributed to
+    /// each signing party
+    pub type SigningPackage = frost::SigningPackage<P>;
+
+    /// Performed once by each participant selected for the signing operation.
+    ///
+    /// Receives the message to be signed and a set of signing commitments and a set
+    /// of randomizing commitments to be used in that signing operation, including
+    /// that for this participant.
+    ///
+    /// Assumes the participant has already determined which nonce corresponds with
+    /// the commitment that was assigned by the coordinator in the SigningPackage.
+    pub fn sign(
+        signing_package: &SigningPackage,
+        signer_nonces: &round1::SigningNonces,
+        key_package: &keys::KeyPackage,
+        randomizer_point: &<<P as Ciphersuite>::Group as Group>::Element,
+    ) -> Result<SignatureShare, Error> {
+        frost_rerandomized::sign(
+            signing_package,
+            signer_nonces,
+            key_package,
+            randomizer_point,
+        )
+    }
+}
+
+/// A Schnorr signature on FROST(Pallas, BLAKE2b-512).
+pub type Signature = frost_rerandomized::frost_core::Signature<P>;
+
+/// Verifies each FROST(Pallas, BLAKE2b-512) participant's signature share, and if all are valid,
+/// aggregates the shares into a signature to publish.
+///
+/// Resulting signature is compatible with verification of a plain Schnorr
+/// signature.
+///
+/// This operation is performed by a coordinator that can communicate with all
+/// the signing participants before publishing the final signature. The
+/// coordinator can be one of the participants or a semi-trusted third party
+/// (who is trusted to not perform denial of service attacks, but does not learn
+/// any secret information). Note that because the coordinator is trusted to
+/// report misbehaving parties in order to avoid publishing an invalid
+/// signature, if the coordinator themselves is a signer and misbehaves, they
+/// can avoid that step. However, at worst, this results in a denial of
+/// service attack due to publishing an invalid signature.
+pub fn aggregate(
+    signing_package: &round2::SigningPackage,
+    signature_shares: &[round2::SignatureShare],
+    pubkeys: &keys::PublicKeyPackage,
+    randomized_params: &RandomizedParams<P>,
+) -> Result<Signature, Error> {
+    frost_rerandomized::aggregate(
+        signing_package,
+        signature_shares,
+        pubkeys,
+        randomized_params,
+    )
+}
+
+/// A signing key for a Schnorr signature on FROST(Pallas, BLAKE2b-512).
+pub type SigningKey = frost_rerandomized::frost_core::SigningKey<P>;
+
+/// A valid verifying key for Schnorr signatures on FROST(Pallas, BLAKE2b-512).
+pub type VerifyingKey = frost_rerandomized::frost_core::VerifyingKey<P>;
--- a/src/frost/redpallas/README.md
+++ b/src/frost/redpallas/README.md
@ -0,0 +1,98 @@
+An implementation of Schnorr signatures on the Pallas curve for both single and threshold numbers
+of signers (FROST).
+
+## Example: key generation with trusted dealer and FROST signing
+
+Creating a key with a trusted dealer and splitting into shares; then signing a message
+and aggregating the signature. Note that the example just simulates a distributed
+scenario in a single thread and it abstracts away any communication between peers.
+
+
+```rust
+use reddsa::frost::redpallas as frost;
+use rand::thread_rng;
+use std::collections::HashMap;
+
+let mut rng = thread_rng();
+let max_signers = 5;
+let min_signers = 3;
+let (shares, pubkeys) = frost::keys::keygen_with_dealer(max_signers, min_signers, &mut rng)?;
+
+// Verifies the secret shares from the dealer and stores them in a HashMap.
+// In practice, each KeyPackage must be sent to its respective participant
+// through a confidential and authenticated channel.
+let key_packages: HashMap<_, _> = shares
+    .into_iter()
+    .map(|share| Ok((share.identifier, frost::keys::KeyPackage::try_from(share)?)))
+    .collect::<Result<_, _>>()?;
+
+let mut nonces = HashMap::new();
+let mut commitments = HashMap::new();
+
+////////////////////////////////////////////////////////////////////////////
+// Round 1: generating nonces and signing commitments for each participant
+////////////////////////////////////////////////////////////////////////////
+
+// In practice, each iteration of this loop will be executed by its respective participant.
+for participant_index in 1..(min_signers as u16 + 1) {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    // Generate one (1) nonce and one SigningCommitments instance for each
+    // participant, up to _threshold_.
+    let (nonce, commitment) = frost::round1::commit(
+        participant_identifier,
+        key_packages[&participant_identifier].secret_share(),
+        &mut rng,
+    );
+    // In practice, the nonces and commitments must be sent to the coordinator
+    // (or to every other participant if there is no coordinator) using
+    // an authenticated channel.
+    nonces.insert(participant_identifier, nonce);
+    commitments.insert(participant_identifier, commitment);
+}
+
+// This is what the signature aggregator / coordinator needs to do:
+// - decide what message to sign
+// - take one (unused) commitment per signing participant
+let mut signature_shares = Vec::new();
+let message = "message to sign".as_bytes();
+let comms = commitments.clone().into_values().collect();
+// In practice, the SigningPackage must be sent to all participants
+// involved in the current signing (at least min_signers participants),
+// using an authenticated channel (and confidential if the message is secret).
+let signing_package = frost::SigningPackage::new(comms, message.to_vec());
+
+////////////////////////////////////////////////////////////////////////////
+// Round 2: each participant generates their signature share
+////////////////////////////////////////////////////////////////////////////
+
+// In practice, each iteration of this loop will be executed by its respective participant.
+for participant_identifier in nonces.keys() {
+    let key_package = &key_packages[participant_identifier];
+
+    let nonces_to_use = &nonces[participant_identifier];
+
+    // Each participant generates their signature share.
+    let signature_share = frost::round2::sign(&signing_package, nonces_to_use, key_package)?;
+
+    // In practice, the signature share must be sent to the Coordinator
+    // using an authenticated channel.
+    signature_shares.push(signature_share);
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Aggregation: collects the signing shares from all participants,
+// generates the final signature.
+////////////////////////////////////////////////////////////////////////////
+
+// Aggregate (also verifies the signature shares)
+let group_signature = frost::aggregate(&signing_package, &signature_shares[..], &pubkeys)?;
+
+// Check that the threshold signature can be verified by the group public
+// key (the verification key).
+assert!(pubkeys
+    .group_public
+    .verify(message, &group_signature)
+    .is_ok());
+
+# Ok::<(), frost::Error>(())
+```
--- a/src/frost/redpallas/dkg.md
+++ b/src/frost/redpallas/dkg.md
@ -0,0 +1,157 @@
+# Distributed Key Generation (DKG)
+
+The DKG module supports generating FROST key shares in a distributed manner,
+without a trusted dealer.
+
+Before starting, each participant needs a unique identifier, which can be built from
+a `u16`. The process in which these identifiers are allocated is up to the application.
+
+The distributed key generation process has 3 parts, with 2 communication rounds
+between them, in which each participant needs to send a "package" to every other
+participant. In the first round, each participant sends the same package
+(a [`Round1Package`]) to every other. In the second round, each receiver gets
+their own package (a [`Round2Package`]).
+
+Between part 1 and 2, each participant needs to hold onto a [`Round1SecretPackage`]
+that MUST be kept secret. Between part 2 and 3, each participant needs to hold
+onto a [`Round2SecretPackage`].
+
+After the third part, each participant will get a [`KeyPackage`] with their
+long-term secret share that must be kept secret, and a [`PublicKeyPackage`]
+that is public (and will be the same between all participants). With those
+they can proceed to sign messages with FROST.
+
+
+## Example
+
+```rust
+use rand::thread_rng;
+use std::collections::HashMap;
+
+use reddsa::frost::redpallas as frost;
+
+let mut rng = thread_rng();
+
+////////////////////////////////////////////////////////////////////////////
+// Key generation, Round 1
+////////////////////////////////////////////////////////////////////////////
+
+let max_signers = 5;
+let min_signers = 3;
+
+// Keep track of each participant's round 1 secret package.
+// In practice each participant will keep its copy; no one
+// will have all the participant's packages.
+let mut round1_secret_packages = HashMap::new();
+
+// Keep track of all round 1 packages sent to the given participant.
+// This is used to simulate the broadcast; in practice the packages
+// will be sent through some communication channel.
+let mut received_round1_packages = HashMap::new();
+
+// For each participant, perform the first part of the DKG protocol.
+// In practice, each participant will perform this on their own environments.
+for participant_index in 1..=max_signers {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    let (secret_package, round1_package) = frost::keys::dkg::keygen_part1(
+        participant_identifier,
+        max_signers,
+        min_signers,
+        &mut rng,
+    )?;
+
+    // Store the participant's secret package for later use.
+    // In practice each participant will store it in their own environment.
+    round1_secret_packages.insert(participant_identifier, secret_package);
+
+    // "Send" the round 1 package to all other participants. In this
+    // test this is simulated using a HashMap; in practice this will be
+    // sent through some communication channel.
+    for receiver_participant_index in 1..=max_signers {
+        if receiver_participant_index == participant_index {
+            continue;
+        }
+        let receiver_participant_identifier: frost::Identifier = receiver_participant_index
+            .try_into()
+            .expect("should be nonzero");
+        received_round1_packages
+            .entry(receiver_participant_identifier)
+            .or_insert_with(Vec::new)
+            .push(round1_package.clone());
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Key generation, Round 2
+////////////////////////////////////////////////////////////////////////////
+
+// Keep track of each participant's round 2 secret package.
+// In practice each participant will keep its copy; no one
+// will have all the participant's packages.
+let mut round2_secret_packages = HashMap::new();
+
+// Keep track of all round 2 packages sent to the given participant.
+// This is used to simulate the broadcast; in practice the packages
+// will be sent through some communication channel.
+let mut received_round2_packages = HashMap::new();
+
+// For each participant, perform the second part of the DKG protocol.
+// In practice, each participant will perform this on their own environments.
+for participant_index in 1..=max_signers {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    let (round2_secret_package, round2_packages) = frost::keys::dkg::keygen_part2(
+        round1_secret_packages
+            .remove(&participant_identifier)
+            .unwrap(),
+        &received_round1_packages[&participant_identifier],
+    )?;
+
+    // Store the participant's secret package for later use.
+    // In practice each participant will store it in their own environment.
+    round2_secret_packages.insert(participant_identifier, round2_secret_package);
+
+    // "Send" the round 2 package to all other participants. In this
+    // test this is simulated using a HashMap; in practice this will be
+    // sent through some communication channel.
+    // Note that, in contrast to the previous part, here each other participant
+    // gets its own specific package.
+    for round2_package in round2_packages {
+        received_round2_packages
+            .entry(round2_package.receiver_identifier)
+            .or_insert_with(Vec::new)
+            .push(round2_package);
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////
+// Key generation, final computation
+////////////////////////////////////////////////////////////////////////////
+
+// Keep track of each participant's long-lived key package.
+// In practice each participant will keep its copy; no one
+// will have all the participant's packages.
+let mut key_packages = HashMap::new();
+
+// Keep track of each participant's public key package.
+// In practice, if there is a Coordinator, only they need to store the set.
+// If there is not, then all candidates must store their own sets.
+// All participants will have the same exact public key package.
+let mut pubkey_packages = HashMap::new();
+
+// For each participant, perform the third part of the DKG protocol.
+// In practice, each participant will perform this on their own environments.
+for participant_index in 1..=max_signers {
+    let participant_identifier = participant_index.try_into().expect("should be nonzero");
+    let (key_package, pubkey_package_for_participant) = frost::keys::dkg::keygen_part3(
+        &round2_secret_packages[&participant_identifier],
+        &received_round1_packages[&participant_identifier],
+        &received_round2_packages[&participant_identifier],
+    )?;
+    key_packages.insert(participant_identifier, key_package);
+    pubkey_packages.insert(participant_identifier, pubkey_package_for_participant);
+}
+
+// With its own key package and the pubkey package, each participant can now proceed
+// to sign with FROST.
+# Ok::<(), frost::Error>(())
+```
--- a/src/hash.rs
+++ b/src/hash.rs
@ -34,6 +34,19 @@ impl<T: SigType> Default for HStar<T> {
 }

 impl<T: SigType> HStar<T> {
+    // Only used by FROST code
+    #[allow(unused)]
+    pub(crate) fn new(personalization_string: &[u8]) -> Self {
+        let state = Params::new()
+            .hash_length(64)
+            .personal(personalization_string)
+            .to_state();
+        Self {
+            state,
+            _marker: PhantomData::default(),
+        }
+    }
+
    /// Add `data` to the hash, and return `Self` for chaining.
    pub fn update(&mut self, data: impl AsRef<[u8]>) -> &mut Self {
        self.state.update(data.as_ref());
--- a/src/lib.rs
+++ b/src/lib.rs
@ -24,6 +24,8 @@ extern crate std;
 pub mod batch;
 mod constants;
 mod error;
+#[cfg(feature = "frost")]
+pub mod frost;
 mod hash;
 pub mod orchard;
 pub mod sapling;
--- a/src/signing_key.rs
+++ b/src/signing_key.rs
@ -31,8 +31,8 @@ pub struct SigningKey<T: SigType> {
    pk: VerificationKey<T>,
 }

-impl<'a, T: SigType> From<&'a SigningKey<T>> for VerificationKey<T> {
-    fn from(sk: &'a SigningKey<T>) -> VerificationKey<T> {
+impl<T: SigType> From<&SigningKey<T>> for VerificationKey<T> {
+    fn from(sk: &SigningKey<T>) -> VerificationKey<T> {
        sk.pk
    }
 }
--- a/tests/frost_redjubjub.rs
+++ b/tests/frost_redjubjub.rs
@ -0,0 +1,85 @@
+#![cfg(feature = "frost")]
+
+use frost_rerandomized::frost_core::{Ciphersuite, Group, GroupError};
+use rand::thread_rng;
+
+use reddsa::{frost::redjubjub::JubjubBlake2b512, sapling};
+
+#[test]
+fn check_sign_with_dealer() {
+    let rng = thread_rng();
+
+    frost_rerandomized::frost_core::tests::check_sign_with_dealer::<JubjubBlake2b512, _>(rng);
+}
+
+#[test]
+fn check_randomized_sign_with_dealer() {
+    let rng = thread_rng();
+
+    let (msg, group_signature, group_pubkey) =
+        frost_rerandomized::tests::check_randomized_sign_with_dealer::<JubjubBlake2b512, _>(rng);
+
+    // Check that the threshold signature can be verified by the `reddsa` crate
+    // public key (interoperability test)
+
+    let sig = {
+        let bytes: [u8; 64] = group_signature.to_bytes().as_ref().try_into().unwrap();
+        reddsa::Signature::<sapling::SpendAuth>::from(bytes)
+    };
+    let pk_bytes = {
+        let bytes: [u8; 32] = group_pubkey.to_bytes().as_ref().try_into().unwrap();
+        reddsa::VerificationKeyBytes::<sapling::SpendAuth>::from(bytes)
+    };
+
+    // Check that the verification key is a valid RedDSA verification key.
+    let pub_key = reddsa::VerificationKey::try_from(pk_bytes)
+        .expect("The test verification key to be well-formed.");
+
+    // Check that signature validation has the expected result.
+    assert!(pub_key.verify(&msg, &sig).is_ok());
+}
+
+#[test]
+fn check_sign_with_dkg() {
+    let rng = thread_rng();
+
+    frost_rerandomized::frost_core::tests::check_sign_with_dkg::<JubjubBlake2b512, _>(rng);
+}
+
+#[test]
+fn check_deserialize_identity() {
+    let encoded_identity = <JubjubBlake2b512 as Ciphersuite>::Group::serialize(
+        &<JubjubBlake2b512 as Ciphersuite>::Group::identity(),
+    );
+    let r = <JubjubBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_identity);
+    assert_eq!(r, Err(GroupError::InvalidIdentityElement));
+}
+
+#[test]
+fn check_deserialize_non_canonical() {
+    let encoded_generator = <JubjubBlake2b512 as Ciphersuite>::Group::serialize(
+        &<JubjubBlake2b512 as Ciphersuite>::Group::generator(),
+    );
+    let r = <JubjubBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_generator);
+    assert!(r.is_ok());
+
+    // This is x = p + 3 which is non-canonical and maps to a valid point.
+    let encoded_point =
+        hex::decode("04000000fffffffffe5bfeff02a4bd5305d8a10908d83933487d9d2953a7ed73")
+            .unwrap()
+            .try_into()
+            .unwrap();
+    let r = <JubjubBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_point);
+    assert_eq!(r, Err(GroupError::MalformedElement));
+}
+
+#[test]
+fn check_deserialize_non_prime_order() {
+    let encoded_point =
+        hex::decode("0300000000000000000000000000000000000000000000000000000000000000")
+            .unwrap()
+            .try_into()
+            .unwrap();
+    let r = <JubjubBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_point);
+    assert_eq!(r, Err(GroupError::InvalidNonPrimeOrderElement));
+}
--- a/tests/frost_redpallas.rs
+++ b/tests/frost_redpallas.rs
@ -0,0 +1,74 @@
+#![cfg(feature = "frost")]
+
+use frost_rerandomized::frost_core::{Ciphersuite, Group, GroupError};
+use rand::thread_rng;
+
+use reddsa::{frost::redpallas::PallasBlake2b512, orchard};
+
+#[test]
+fn check_sign_with_dealer() {
+    let rng = thread_rng();
+
+    frost_rerandomized::frost_core::tests::check_sign_with_dealer::<PallasBlake2b512, _>(rng);
+}
+
+#[test]
+fn check_randomized_sign_with_dealer() {
+    let rng = thread_rng();
+
+    let (msg, group_signature, group_pubkey) =
+        frost_rerandomized::tests::check_randomized_sign_with_dealer::<PallasBlake2b512, _>(rng);
+
+    // Check that the threshold signature can be verified by the `reddsa` crate
+    // public key (interoperability test)
+
+    let sig = {
+        let bytes: [u8; 64] = group_signature.to_bytes().as_ref().try_into().unwrap();
+        reddsa::Signature::<orchard::SpendAuth>::from(bytes)
+    };
+    let pk_bytes = {
+        let bytes: [u8; 32] = group_pubkey.to_bytes().as_ref().try_into().unwrap();
+        reddsa::VerificationKeyBytes::<orchard::SpendAuth>::from(bytes)
+    };
+
+    // Check that the verification key is a valid RedDSA verification key.
+    let pub_key = reddsa::VerificationKey::try_from(pk_bytes)
+        .expect("The test verification key to be well-formed.");
+
+    // Check that signature validation has the expected result.
+    assert!(pub_key.verify(&msg, &sig).is_ok());
+}
+
+#[test]
+fn check_sign_with_dkg() {
+    let rng = thread_rng();
+
+    frost_rerandomized::frost_core::tests::check_sign_with_dkg::<PallasBlake2b512, _>(rng);
+}
+
+#[test]
+fn check_deserialize_identity() {
+    let encoded_identity = <PallasBlake2b512 as Ciphersuite>::Group::serialize(
+        &<PallasBlake2b512 as Ciphersuite>::Group::identity(),
+    );
+    let r = <PallasBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_identity);
+    assert_eq!(r, Err(GroupError::InvalidIdentityElement));
+}
+
+#[test]
+fn check_deserialize_non_canonical() {
+    let encoded_generator = <PallasBlake2b512 as Ciphersuite>::Group::serialize(
+        &<PallasBlake2b512 as Ciphersuite>::Group::generator(),
+    );
+    let r = <PallasBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_generator);
+    assert!(r.is_ok());
+
+    // This is x = p + 3 which is non-canonical and maps to a valid point.
+    let encoded_point =
+        hex::decode("04000000ed302d991bf94c09fc98462200000000000000000000000000000040")
+            .unwrap()
+            .try_into()
+            .unwrap();
+    let r = <PallasBlake2b512 as Ciphersuite>::Group::deserialize(&encoded_point);
+    assert_eq!(r, Err(GroupError::MalformedElement));
+}