Files
opaque-vx/src/messages.rs
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466 lines
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Rust

// Copyright (c) Meta Platforms, Inc. and affiliates.
//
// This source code is dual-licensed under either the MIT license found in the
// LICENSE-MIT file in the root directory of this source tree or the Apache
// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
// of this source tree. You may select, at your option, one of the above-listed
// licenses.
//! Contains the messages used for OPAQUE
use core::ops::Add;
use derive_where::derive_where;
use digest::Output;
use generic_array::sequence::Concat;
use generic_array::typenum::{Sum, Unsigned};
use generic_array::{ArrayLength, GenericArray};
use rand::{CryptoRng, RngCore};
use voprf::{BlindedElement, BlindedElementLen, EvaluationElement, EvaluationElementLen};
use zeroize::Zeroizing;
use crate::ciphersuite::{CipherSuite, KeGroup, OprfGroup, OprfHash};
use crate::envelope::{Envelope, EnvelopeLen};
use crate::errors::ProtocolError;
use crate::hash::OutputSize;
use crate::key_exchange::group::Group;
use crate::key_exchange::shared::NonceLen;
use crate::key_exchange::traits::{
CredentialRequestParts, CredentialResponseParts, Deserialize, Ke1MessageLen, Ke2MessageLen,
Ke3MessageLen, KeyExchange, Serialize,
};
use crate::keypair::PublicKey;
use crate::opaque::{
MaskedResponse, MaskedResponseLen, ServerLogin, ServerLoginStartResult, ServerSetup,
};
use crate::serialization::SliceExt;
////////////////////////////
// High-level API Structs //
// ====================== //
////////////////////////////
/// The message sent by the client to the server, to initiate registration
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound = "")
)]
#[derive_where(Clone)]
#[derive_where(Debug, Eq, Hash, Ord, PartialEq, PartialOrd; voprf::BlindedElement<CS::OprfCs>)]
pub struct RegistrationRequest<CS: CipherSuite> {
/// blinded password information
pub(crate) blinded_element: voprf::BlindedElement<CS::OprfCs>,
}
/// The answer sent by the server to the user, upon reception of the
/// registration attempt
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound = "")
)]
#[derive_where(Clone)]
#[derive_where(Debug, Eq, Hash, Ord, PartialEq, PartialOrd; voprf::EvaluationElement<CS::OprfCs>, <KeGroup<CS> as Group>::Pk)]
pub struct RegistrationResponse<CS: CipherSuite> {
/// The server's oprf output
pub(crate) evaluation_element: voprf::EvaluationElement<CS::OprfCs>,
/// Server's static public key
pub(crate) server_s_pk: PublicKey<KeGroup<CS>>,
}
/// The final message from the client, containing sealed cryptographic
/// identifiers
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound = "")
)]
#[derive_where(Clone, ZeroizeOnDrop)]
#[derive_where(Debug, Eq, Hash, Ord, PartialEq, PartialOrd; <KeGroup<CS> as Group>::Pk)]
pub struct RegistrationUpload<CS: CipherSuite> {
/// The "envelope" generated by the user, containing sealed cryptographic
/// identifiers
pub(crate) envelope: Envelope<CS>,
/// The masking key used to mask the envelope
pub(crate) masking_key: Output<OprfHash<CS>>,
/// The user's public key
pub(crate) client_s_pk: PublicKey<KeGroup<CS>>,
}
/// The message sent by the user to the server, to initiate registration
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound(
deserialize = "<CS::KeyExchange as KeyExchange>::KE1Message: serde::Deserialize<'de>",
serialize = "<CS::KeyExchange as KeyExchange>::KE1Message: serde::Serialize"
))
)]
#[derive_where(Clone, ZeroizeOnDrop)]
#[derive_where(
Debug, Eq, Hash, PartialEq;
voprf::BlindedElement<CS::OprfCs>,
<CS::KeyExchange as KeyExchange>::KE1Message,
)]
pub struct CredentialRequest<CS: CipherSuite> {
pub(crate) blinded_element: voprf::BlindedElement<CS::OprfCs>,
pub(crate) ke1_message: <CS::KeyExchange as KeyExchange>::KE1Message,
}
/// Builder for [`ServerLogin`](crate::ServerLogin) when using remote keys.
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound(
deserialize = "SK: serde::Deserialize<'de>, <CS::KeyExchange as \
KeyExchange>::KE2Builder<'a, CS>: serde::Deserialize<'de>",
serialize = "SK: serde::Serialize, <CS::KeyExchange as KeyExchange>::KE2Builder<'a, CS>: \
serde::Serialize"
))
)]
#[derive_where(Clone)]
#[derive_where(
Debug, Eq, PartialEq;
<KeGroup<CS> as Group>::Pk,
SK,
voprf::EvaluationElement<CS::OprfCs>,
<CS::KeyExchange as KeyExchange>::KE2Builder<'a, CS>,
)]
pub struct ServerLoginBuilder<'a, CS: CipherSuite, SK: Clone> {
pub(crate) server_s_sk: SK,
pub(crate) evaluation_element: voprf::EvaluationElement<CS::OprfCs>,
pub(crate) masking_nonce: Zeroizing<GenericArray<u8, NonceLen>>,
pub(crate) masked_response: MaskedResponse<CS>,
#[cfg(test)]
pub(crate) oprf_key: Zeroizing<GenericArray<u8, <OprfGroup<CS> as voprf::Group>::ScalarLen>>,
pub(crate) ke2_builder: <CS::KeyExchange as KeyExchange>::KE2Builder<'a, CS>,
}
impl<CS: CipherSuite, SK: Clone> ServerLoginBuilder<'_, CS, SK> {
/// The returned data here has to be processed and the result given as an
/// input to [`ServerLoginBuilder::build()`]. To understand what kind of
/// output is expected here and how to process it, refer to the
/// documentation of your chosen [`CipherSuite::KeyExchange`].
pub fn data(&self) -> <CS::KeyExchange as KeyExchange>::KE2BuilderData<'_, CS> {
CS::KeyExchange::ke2_builder_data(&self.ke2_builder)
}
/// The handle to the corresponding [`ServerSetup`]s private key.
pub fn private_key(&self) -> &SK {
&self.server_s_sk
}
/// Build [`ServerLogin`] after attaining the input for the key exchange. To
/// understand what kind of input is expected here, refer to the
/// documentation of your chosen [`CipherSuite::KeyExchange`].
///
/// See [`ServerLogin::start()`] for the regular path.
pub fn build(
self,
input: <CS::KeyExchange as KeyExchange>::KE2BuilderInput<CS>,
) -> Result<ServerLoginStartResult<CS>, ProtocolError> {
ServerLogin::build(self, input)
}
}
/// The answer sent by the server to the user, upon reception of the login
/// attempt
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound(
deserialize = "<CS::KeyExchange as KeyExchange>::KE2Message: serde::Deserialize<'de>",
serialize = "<CS::KeyExchange as KeyExchange>::KE2Message: serde::Serialize"
))
)]
#[derive_where(Clone)]
#[derive_where(
Debug, Eq, Hash, PartialEq;
voprf::EvaluationElement<CS::OprfCs>,
<CS::KeyExchange as KeyExchange>::KE2Message,
)]
pub struct CredentialResponse<CS: CipherSuite> {
/// the server's oprf output
pub(crate) evaluation_element: voprf::EvaluationElement<CS::OprfCs>,
pub(crate) masking_nonce: GenericArray<u8, NonceLen>,
pub(crate) masked_response: MaskedResponse<CS>,
pub(crate) ke2_message: <CS::KeyExchange as KeyExchange>::KE2Message,
}
/// The answer sent by the client to the server, upon reception of the sealed
/// envelope
#[cfg_attr(
feature = "serde",
derive(serde::Deserialize, serde::Serialize),
serde(bound(
deserialize = "<CS::KeyExchange as KeyExchange>::KE3Message: serde::Deserialize<'de>",
serialize = "<CS::KeyExchange as KeyExchange>::KE3Message: serde::Serialize"
))
)]
#[derive_where(Clone)]
#[derive_where(
Debug, Eq, Hash, PartialEq;
<CS::KeyExchange as KeyExchange>::KE3Message,
)]
pub struct CredentialFinalization<CS: CipherSuite> {
pub(crate) ke3_message: <CS::KeyExchange as KeyExchange>::KE3Message,
}
////////////////////////////////
// High-level Implementations //
// ========================== //
////////////////////////////////
/// Length of [`RegistrationRequest`] in bytes for serialization.
pub type RegistrationRequestLen<CS: CipherSuite> = <OprfGroup<CS> as voprf::Group>::ElemLen;
impl<CS: CipherSuite> RegistrationRequest<CS> {
/// Only used for testing purposes
#[cfg(test)]
pub(crate) fn get_blinded_element_for_testing(&self) -> voprf::BlindedElement<CS::OprfCs> {
self.blinded_element.clone()
}
/// Serialization into bytes
pub fn serialize(&self) -> GenericArray<u8, RegistrationRequestLen<CS>> {
<OprfGroup<CS> as voprf::Group>::serialize_elem(self.blinded_element.value())
}
/// Deserialization from bytes
pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
Ok(Self {
blinded_element: voprf::BlindedElement::deserialize(input)?,
})
}
}
/// Length of [`RegistrationResponse`] in bytes for serialization.
pub type RegistrationResponseLen<CS: CipherSuite> =
Sum<<OprfGroup<CS> as voprf::Group>::ElemLen, <KeGroup<CS> as Group>::PkLen>;
impl<CS: CipherSuite> RegistrationResponse<CS> {
/// Serialization into bytes
pub fn serialize(&self) -> GenericArray<u8, RegistrationResponseLen<CS>>
where
// RegistrationResponse: KgPk + KePk
<OprfGroup<CS> as voprf::Group>::ElemLen: Add<<KeGroup<CS> as Group>::PkLen>,
RegistrationResponseLen<CS>: ArrayLength<u8>,
{
<OprfGroup<CS> as voprf::Group>::serialize_elem(self.evaluation_element.value())
.concat(self.server_s_pk.serialize())
}
/// Deserialization from bytes
pub fn deserialize(mut input: &[u8]) -> Result<Self, ProtocolError> {
let evaluation_element = EvaluationElement::deserialize(input)?;
input = &input[EvaluationElementLen::<CS::OprfCs>::USIZE..];
Ok(Self {
evaluation_element,
server_s_pk: PublicKey::deserialize_take(&mut input)?,
})
}
#[cfg(test)]
/// Only used for tests, where we can set the beta value to test for the
/// reflection error case
pub(crate) fn set_evaluation_element_for_testing(
&self,
beta: <OprfGroup<CS> as voprf::Group>::Elem,
) -> Self {
Self {
evaluation_element: voprf::EvaluationElement::from_value_unchecked(beta),
server_s_pk: self.server_s_pk.clone(),
}
}
}
/// Length of [`RegistrationUpload`] in bytes for serialization.
pub type RegistrationUploadLen<CS: CipherSuite> =
Sum<Sum<<KeGroup<CS> as Group>::PkLen, OutputSize<OprfHash<CS>>>, EnvelopeLen<CS>>;
impl<CS: CipherSuite> RegistrationUpload<CS> {
/// Serialization into bytes
pub fn serialize(&self) -> GenericArray<u8, RegistrationUploadLen<CS>>
where
// RegistrationUpload: (KePk + Hash) + Envelope
<KeGroup<CS> as Group>::PkLen: Add<OutputSize<OprfHash<CS>>>,
Sum<<KeGroup<CS> as Group>::PkLen, OutputSize<OprfHash<CS>>>:
ArrayLength<u8> + Add<EnvelopeLen<CS>>,
RegistrationUploadLen<CS>: ArrayLength<u8>,
{
self.client_s_pk
.serialize()
.concat(self.masking_key.clone())
.concat(self.envelope.serialize())
}
/// Deserialization from bytes
pub fn deserialize(mut input: &[u8]) -> Result<Self, ProtocolError> {
Ok(Self {
client_s_pk: PublicKey::deserialize_take(&mut input)?,
masking_key: input.take_array("masking key")?,
envelope: Envelope::deserialize_take(&mut input)?,
})
}
// Creates a dummy instance used for faking a [CredentialResponse]
pub(crate) fn dummy<R: RngCore + CryptoRng, SK: Clone, OS: Clone>(
rng: &mut R,
server_setup: &ServerSetup<CS, SK, OS>,
) -> Self {
let mut masking_key = Output::<OprfHash<CS>>::default();
rng.fill_bytes(&mut masking_key);
Self {
envelope: Envelope::<CS>::dummy(),
masking_key,
client_s_pk: server_setup.dummy_pk.clone(),
}
}
}
/// Length of [`CredentialRequest`] in bytes for serialization.
pub type CredentialRequestLen<CS: CipherSuite> =
Sum<<OprfGroup<CS> as voprf::Group>::ElemLen, Ke1MessageLen<CS>>;
impl<CS: CipherSuite> CredentialRequest<CS> {
/// Serialization into bytes
pub fn serialize(&self) -> GenericArray<u8, CredentialRequestLen<CS>>
where
<CS::KeyExchange as KeyExchange>::KE1Message: Serialize,
// CredentialRequest: KgPk + Ke1Message
<OprfGroup<CS> as voprf::Group>::ElemLen: Add<Ke1MessageLen<CS>>,
CredentialRequestLen<CS>: ArrayLength<u8>,
{
<OprfGroup<CS> as voprf::Group>::serialize_elem(self.blinded_element.value())
.concat(self.ke1_message.serialize())
}
/// Deserialization from bytes
pub fn deserialize(mut input: &[u8]) -> Result<Self, ProtocolError>
where
<CS::KeyExchange as KeyExchange>::KE1Message: Deserialize,
{
Self::deserialize_take(&mut input)
}
pub(crate) fn deserialize_take(input: &mut &[u8]) -> Result<Self, ProtocolError>
where
<CS::KeyExchange as KeyExchange>::KE1Message: Deserialize,
{
let blinded_element = BlindedElement::deserialize(input)?;
*input = &input[BlindedElementLen::<CS::OprfCs>::USIZE..];
Ok(Self {
blinded_element,
ke1_message: <CS::KeyExchange as KeyExchange>::KE1Message::deserialize_take(input)?,
})
}
pub(crate) fn to_parts(&self) -> CredentialRequestParts<CS> {
CredentialRequestParts::new(&self.blinded_element)
}
/// Only used for testing purposes
#[cfg(test)]
pub(crate) fn get_blinded_element_for_testing(&self) -> voprf::BlindedElement<CS::OprfCs> {
self.blinded_element.clone()
}
}
/// Length of [`CredentialResponse`] in bytes for serialization.
pub type CredentialResponseLen<CS: CipherSuite> =
Sum<CredentialResponseWithoutKeLen<CS>, Ke2MessageLen<CS>>;
pub(crate) type CredentialResponseWithoutKeLen<CS: CipherSuite> =
Sum<Sum<<OprfGroup<CS> as voprf::Group>::ElemLen, NonceLen>, MaskedResponseLen<CS>>;
impl<CS: CipherSuite> CredentialResponse<CS> {
/// Serialization into bytes
pub fn serialize(&self) -> GenericArray<u8, CredentialResponseLen<CS>>
where
<CS::KeyExchange as KeyExchange>::KE2Message: Serialize,
// CredentialResponseWithoutKeLen: (KgPk + Nonce) + MaskedResponse
<OprfGroup<CS> as voprf::Group>::ElemLen: Add<NonceLen>,
Sum<<OprfGroup<CS> as voprf::Group>::ElemLen, NonceLen>:
ArrayLength<u8> + Add<MaskedResponseLen<CS>>,
CredentialResponseWithoutKeLen<CS>: ArrayLength<u8>,
// CredentialResponse: CredentialResponseWithoutKeLen + Ke2Message
CredentialResponseWithoutKeLen<CS>: Add<Ke2MessageLen<CS>>,
CredentialResponseLen<CS>: ArrayLength<u8>,
{
<OprfGroup<CS> as voprf::Group>::serialize_elem(self.evaluation_element.value())
.concat(self.masking_nonce)
.concat(self.masked_response.serialize())
.concat(self.ke2_message.serialize())
}
/// Deserialization from bytes
pub fn deserialize(mut input: &[u8]) -> Result<Self, ProtocolError>
where
<CS::KeyExchange as KeyExchange>::KE2Message: Deserialize,
{
let evaluation_element = EvaluationElement::deserialize(input)?;
input = &input[voprf::EvaluationElementLen::<CS::OprfCs>::USIZE..];
Ok(Self {
evaluation_element,
masking_nonce: input.take_array("masking nonce")?,
masked_response: MaskedResponse::deserialize_take(&mut input)?,
ke2_message: <CS::KeyExchange as KeyExchange>::KE2Message::deserialize_take(
&mut input,
)?,
})
}
pub(crate) fn to_parts(&self) -> CredentialResponseParts<CS> {
CredentialResponseParts::new(
&self.evaluation_element,
self.masking_nonce,
self.masked_response.clone(),
)
}
#[cfg(test)]
/// Only used for tests, where we can set the beta value to test for the
/// reflection error case
pub(crate) fn set_evaluation_element_for_testing(
&self,
beta: <OprfGroup<CS> as voprf::Group>::Elem,
) -> Self {
Self {
evaluation_element: voprf::EvaluationElement::from_value_unchecked(beta),
masking_nonce: self.masking_nonce,
masked_response: self.masked_response.clone(),
ke2_message: self.ke2_message.clone(),
}
}
}
/// Length of [`CredentialFinalization`] in bytes for serialization.
pub type CredentialFinalizationLen<CS: CipherSuite> = Ke3MessageLen<CS>;
impl<CS: CipherSuite> CredentialFinalization<CS> {
/// Serialization into bytes
pub fn serialize(&self) -> GenericArray<u8, CredentialFinalizationLen<CS>>
where
<CS::KeyExchange as KeyExchange>::KE3Message: Serialize,
{
self.ke3_message.serialize()
}
/// Deserialization from bytes
pub fn deserialize(mut input: &[u8]) -> Result<Self, ProtocolError>
where
<CS::KeyExchange as KeyExchange>::KE3Message: Deserialize,
{
Ok(Self {
ke3_message: <CS::KeyExchange as KeyExchange>::KE3Message::deserialize_take(
&mut input,
)?,
})
}
}