// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license. use curve25519_dalek::montgomery::MontgomeryPoint; use deno_core::error::AnyError; use deno_core::op; use deno_core::ZeroCopyBuf; use elliptic_curve::pkcs8::PrivateKeyInfo; use elliptic_curve::subtle::ConstantTimeEq; use rand::rngs::OsRng; use rand::RngCore; use spki::der::Decode; use spki::der::Encode; #[op(fast)] pub fn op_generate_x25519_keypair(pkey: &mut [u8], pubkey: &mut [u8]) { // u-coordinate of the base point. const X25519_BASEPOINT_BYTES: [u8; 32] = [ 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ]; let mut rng = OsRng; rng.fill_bytes(pkey); // https://www.rfc-editor.org/rfc/rfc7748#section-6.1 // pubkey = x25519(a, 9) which is constant-time Montgomery ladder. // https://eprint.iacr.org/2014/140.pdf page 4 // https://eprint.iacr.org/2017/212.pdf algorithm 8 // pubkey is in LE order. let pkey: [u8; 32] = pkey.try_into().expect("Expected byteLength 32"); pubkey.copy_from_slice(&x25519_dalek::x25519(pkey, X25519_BASEPOINT_BYTES)); } const MONTGOMERY_IDENTITY: MontgomeryPoint = MontgomeryPoint([0; 32]); #[op(fast)] pub fn op_derive_bits_x25519(k: &[u8], u: &[u8], secret: &mut [u8]) -> bool { let k: [u8; 32] = k.try_into().expect("Expected byteLength 32"); let u: [u8; 32] = u.try_into().expect("Expected byteLength 32"); let sh_sec = x25519_dalek::x25519(k, u); let point = MontgomeryPoint(sh_sec); if point.ct_eq(&MONTGOMERY_IDENTITY).unwrap_u8() == 1 { return false; } secret.copy_from_slice(&sh_sec); true } // id-X25519 OBJECT IDENTIFIER ::= { 1 3 101 110 } pub const X25519_OID: const_oid::ObjectIdentifier = const_oid::ObjectIdentifier::new_unwrap("1.3.101.110"); #[op(fast)] pub fn op_import_spki_x25519(key_data: &[u8], out: &mut [u8]) -> bool { // 2-3. let pk_info = match spki::SubjectPublicKeyInfo::from_der(key_data) { Ok(pk_info) => pk_info, Err(_) => return false, }; // 4. let alg = pk_info.algorithm.oid; if alg != X25519_OID { return false; } // 5. if pk_info.algorithm.parameters.is_some() { return false; } out.copy_from_slice(pk_info.subject_public_key); true } #[op(fast)] pub fn op_import_pkcs8_x25519(key_data: &[u8], out: &mut [u8]) -> bool { // 2-3. // This should probably use OneAsymmetricKey instead let pk_info = match PrivateKeyInfo::from_der(key_data) { Ok(pk_info) => pk_info, Err(_) => return false, }; // 4. let alg = pk_info.algorithm.oid; if alg != X25519_OID { return false; } // 5. if pk_info.algorithm.parameters.is_some() { return false; } // 6. // CurvePrivateKey ::= OCTET STRING if pk_info.private_key.len() != 34 { return false; } out.copy_from_slice(&pk_info.private_key[2..]); true } #[op] pub fn op_export_spki_x25519(pubkey: &[u8]) -> Result { let key_info = spki::SubjectPublicKeyInfo { algorithm: spki::AlgorithmIdentifier { // id-X25519 oid: X25519_OID, parameters: None, }, subject_public_key: pubkey, }; Ok(key_info.to_vec()?.into()) } #[op] pub fn op_export_pkcs8_x25519(pkey: &[u8]) -> Result { // This should probably use OneAsymmetricKey instead let pk_info = rsa::pkcs8::PrivateKeyInfo { public_key: None, algorithm: rsa::pkcs8::AlgorithmIdentifier { // id-X25519 oid: X25519_OID, parameters: None, }, private_key: pkey, // OCTET STRING }; Ok(pk_info.to_vec()?.into()) }