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tbrezottbrezot
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implement an OpenSSL provider -- P256
1 parent d225901 commit eb95f9c

9 files changed

Lines changed: 757 additions & 3 deletions

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‎Cargo.lock‎

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‎Cargo.toml‎

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[workspace]
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members = ["crates/core", "crates/rust_nist_ec", "crates/rust_curve25519"]
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members = [
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"crates/core",
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"crates/openssl_provider",
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"crates/rust_nist_ec",
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"crates/rust_curve25519"
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]
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resolver = "2"
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[workspace.package]

‎crates/core/src/error.rs‎

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@@ -22,7 +22,6 @@ pub enum CryptoCoreError {
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given: usize,
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expected: usize,
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},
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#[cfg(any(feature = "nist_curves", feature = "curve25519"))]
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EllipticCurveError(String),
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EncryptionError,
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GenericDeserializationError(String),
@@ -85,7 +84,6 @@ impl Display for CryptoCoreError {
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f,
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"wrong size when parsing bytes: {given} given should be {expected}"
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),
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#[cfg(any(feature = "nist_curves", feature = "curve25519"))]
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CryptoCoreError::EllipticCurveError(e) => write!(f, "NIST elliptic curve error: {e}"),
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CryptoCoreError::EncryptionError => write!(f, "error during encryption"),
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CryptoCoreError::GenericDeserializationError(err) => {

‎crates/openssl_provider/Cargo.toml‎

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[package]
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name = "cosmian_openssl_provider"
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version = "1.0.0"
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description = "OpenSSL cryptographic provider."
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authors = { workspace = true }
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categories = { workspace = true }
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edition = { workspace = true }
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keywords = { workspace = true }
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license = { workspace = true }
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repository = { workspace = true }
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[lib]
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crate-type = ["lib", "staticlib"]
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name = "cosmian_openssl_provider"
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path = "src/lib.rs"
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[dependencies]
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cosmian_crypto_core = { path = "../core", version = "10.4", default-features = false }
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openssl = { version = "0.10", default-features = false }
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zeroize = { workspace = true }
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[dev-dependencies]
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cosmian_crypto_core = { path = "../core", version = "10.4", default-features = false, features = ["sha3"] }

‎crates/openssl_provider/src/kem.rs‎

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use crate::FFIMonad;
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use cosmian_crypto_core::{
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bytes_ser_de::Serializable,
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reexport::rand_core::CryptoRngCore,
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traits::{CyclicGroup, Field, KDF, KEM, NIKE},
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CryptoCoreError, Sampling, SymmetricKey,
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};
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use std::{
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marker::PhantomData,
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ops::{Add, Div, Mul, Neg, Sub},
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};
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use zeroize::ZeroizeOnDrop;
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#[derive(Debug, Clone, Copy, Default)]
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pub struct MonadicKEM<const KEY_LENGTH: usize, Group: CyclicGroup, Kdf: KDF<KEY_LENGTH>>
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where
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Group::Element: FFIMonad,
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Group::Multiplicity: FFIMonad,
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for<'a> &'a Group::Element: Neg<Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Add<&'b Group::Element, Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Sub<&'b Group::Element, Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Mul<Group::Multiplicity, Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Mul<&'b Group::Multiplicity, Output = Group::Element>,
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for<'a> &'a Group::Multiplicity: Neg<Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Add<&'b Group::Multiplicity, Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Sub<&'b Group::Multiplicity, Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Mul<&'b Group::Multiplicity, Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Div<
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&'b Group::Multiplicity,
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Output = Result<Group::Multiplicity, <Group::Multiplicity as Field>::InvError>,
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>,
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{
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data: PhantomData<(Group, Kdf)>,
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}
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impl<const KEY_LENGTH: usize, Group: CyclicGroup, Kdf: KDF<KEY_LENGTH>> KEM<KEY_LENGTH>
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for MonadicKEM<KEY_LENGTH, Group, Kdf>
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where
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Group::Element: FFIMonad + Serializable + ZeroizeOnDrop,
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Group::Multiplicity: FFIMonad + Sampling + ZeroizeOnDrop,
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for<'a> &'a Group::Element: Neg<Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Add<&'b Group::Element, Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Sub<&'b Group::Element, Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Mul<Group::Multiplicity, Output = Group::Element>,
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for<'a, 'b> &'a Group::Element: Mul<&'b Group::Multiplicity, Output = Group::Element>,
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for<'a> &'a Group::Multiplicity: Neg<Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Add<&'b Group::Multiplicity, Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Sub<&'b Group::Multiplicity, Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Mul<&'b Group::Multiplicity, Output = Group::Multiplicity>,
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for<'a, 'b> &'a Group::Multiplicity: Div<
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&'b Group::Multiplicity,
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Output = Result<Group::Multiplicity, <Group::Multiplicity as Field>::InvError>,
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>,
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{
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type Encapsulation = Group::Element;
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type EncapsulationKey = Group::Element;
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type DecapsulationKey = Group::Multiplicity;
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type Error = CryptoCoreError;
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fn keygen(
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rng: &mut impl CryptoRngCore,
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) -> Result<(Self::DecapsulationKey, Self::EncapsulationKey), Self::Error> {
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let (sk, pk) = <Group as NIKE>::keygen(rng)?;
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let sk = sk.manage_error(|e| {
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CryptoCoreError::EllipticCurveError(format!("secret key is in error state: {e}"))
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})?;
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let pk = pk.manage_error(|e| {
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CryptoCoreError::EllipticCurveError(format!("public key is in error state: {e}"))
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})?;
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Ok((sk, pk))
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}
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fn enc(
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ek: &Self::EncapsulationKey,
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rng: &mut impl CryptoRngCore,
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) -> Result<(SymmetricKey<KEY_LENGTH>, Self::Encapsulation), Self::Error> {
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let (sk, pk) = <Group as NIKE>::keygen(rng)?;
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let ss = (ek * sk).manage_error(|e| {
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CryptoCoreError::EllipticCurveError(format!("shared secret is in error state: {e}"))
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})?;
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let pk = pk.manage_error(|e| {
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CryptoCoreError::EllipticCurveError(format!("public key is in error state: {e}"))
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})?;
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let key = Kdf::derive(
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&ss.serialize()
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.map_err(|e| CryptoCoreError::GenericDeserializationError(e.to_string()))?,
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&[],
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);
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Ok((key, pk))
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}
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fn dec(
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dk: &Self::DecapsulationKey,
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enc: &Self::Encapsulation,
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) -> Result<SymmetricKey<KEY_LENGTH>, Self::Error> {
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let ss = <Group as NIKE>::shared_secret(dk, enc)?.manage_error(|e| {
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CryptoCoreError::EllipticCurveError(format!("shared secret is in error state: {e}"))
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})?;
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let key = Kdf::derive(
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&ss.serialize()
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.map_err(|e| CryptoCoreError::GenericDeserializationError(e.to_string()))?,
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&[],
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);
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Ok(key)
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}
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}

‎crates/openssl_provider/src/lib.rs‎

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//! This crate implements a cryptographic provider on top of the OpenSSL
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//! bindings. Those bindings do not fit well with the arithmetic traits defined
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//! in CryptoCore: since all operations are performed through FFI, the all --
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//! even those as simple as returning the 0 -- are fallible.
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//!
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//! Instead of modifying all arithmetic traits, which would imply the need to
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//! unwrap upon every single arithmetic operation, this provider has been design
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//! in a monadic style: elements are FFI monads that can either be a valid
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//! object or in an error state (the `openssl::ErrorStack` error type) and
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//! comply with arithmetic traits. The only quirk is that the caller is then
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//! required to check the monad state at some point, which leaks an internal
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//! detail.
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//!
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//! To ease its usage, a dedicated KEM is implemented which performs the check
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//! of the monad state when necessary (using the `GenericKEM` from CryptoCore
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//! would return a monad instead of the proper keys or encapsulation).
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pub mod kem;
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pub mod p256;
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/// An FFI monad is either in an OK or error state.
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pub trait FFIMonad: Sized {
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/// Type of the error state.
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type Error: std::error::Error;
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/// Return true if this monad is in its OK state.
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fn is_ok(&self) -> bool;
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/// Returns true if this monad is in its error state.
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fn is_err(&self) -> bool {
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!self.is_ok()
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}
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/// Return this monad unchanged if it is in its OK state, or apply the given
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/// function on its error state.
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fn manage_error<E: std::error::Error>(self, f: fn(Self::Error) -> E) -> Result<Self, E>;
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}

‎crates/openssl_provider/src/p256.rs‎

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mod point;
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mod scalar;
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pub use point::P256Point;
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pub use scalar::P256Scalar;
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use cosmian_crypto_core::traits::CyclicGroup;
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use openssl::nid::Nid;
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const NID: Nid = Nid::X9_62_PRIME256V1;
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#[derive(Debug, Clone, Copy, Default)]
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pub struct P256;
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impl CyclicGroup for P256 {
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type Element = P256Point;
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type Multiplicity = P256Scalar;
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::kem::MonadicKEM;
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use cosmian_crypto_core::{
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kdf::Kdf256,
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traits::tests::{test_cyclic_group, test_kem, test_nike},
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};
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#[test]
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fn test_p256() {
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test_cyclic_group::<P256>();
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test_nike::<P256>();
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test_kem::<32, MonadicKEM<32, P256, Kdf256>>();
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}
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}

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