keyfork-derive-util: make variable-length seeds opt-in

This commit is contained in:
Ryan Heywood 2024-02-12 00:02:59 -05:00
parent 4354be4304
commit 053902bf43
Signed by: ryan
GPG Key ID: 8E401478A3FBEF72
15 changed files with 132 additions and 41 deletions

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@ -47,7 +47,7 @@ fn secp256k1() {
);
let response =
DerivationResponse::try_from(client.request(&req.into()).unwrap()).unwrap();
assert_eq!(response.data, test.private_key);
assert_eq!(&response.data, test.private_key.as_slice());
}
handle.abort();
@ -92,7 +92,7 @@ fn ed25519() {
);
let response =
DerivationResponse::try_from(client.request(&req.into()).unwrap()).unwrap();
assert_eq!(response.data, test.private_key);
assert_eq!(&response.data, test.private_key.as_slice());
}
handle.abort();

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@ -76,7 +76,7 @@ impl Service<Request> for Keyforkd {
info!("Deriving path: {}", req.path());
}
req.derive_with_master_seed((*seed).clone())
req.derive_with_master_seed(seed.as_ref())
.map(Response::Derivation)
.map_err(|e| DerivationError::Derivation(e.to_string()).into())
}),
@ -120,7 +120,7 @@ mod tests {
.unwrap()
.try_into()
.unwrap();
assert_eq!(response.data, test.private_key);
assert_eq!(&response.data, test.private_key.as_slice());
assert_eq!(response.chain_code.as_slice(), test.chain_code);
}
}
@ -150,7 +150,7 @@ mod tests {
.unwrap()
.try_into()
.unwrap();
assert_eq!(response.data, test.private_key);
assert_eq!(&response.data, test.private_key.as_slice());
assert_eq!(response.chain_code.as_slice(), test.chain_code);
}
}

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@ -40,7 +40,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
let key1 = request.derive_with_mnemonic(&mnemonic)?;
let seed = mnemonic.seed(None)?;
let key2 = request.derive_with_master_seed(seed)?;
let key2 = request.derive_with_master_seed(&seed)?;
assert_eq!(key1, key2);

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@ -31,6 +31,68 @@ type Result<T, E = Error> = std::result::Result<T, E>;
type ChainCode = [u8; 32];
type HmacSha512 = Hmac<Sha512>;
/// A reference to a variable-length seed. Keyfork automatically supports a seed of 128 bits,
/// 256 bits, or 512 bits, but because the master key is derived from a hashed seed, in theory
/// any amount of bytes could be used. It is not advised to use a variable-length seed longer
/// than 256 bits, as a brute-force attack on the master key could be performed in 2^256
/// attempts.
///
/// Mnemonics use a 512 bit seed, as knowledge of the mnemonics' words (such as through a side
/// channel attack) could leak which individual word is used, but not the order the words are
/// used in. Using a 512 bit hash to generate the seed results in a more computationally
/// expensive brute-force requirement.
pub struct VariableLengthSeed<'a> {
seed: &'a [u8],
}
impl<'a> VariableLengthSeed<'a> {
/// Create a new VariableLengthSeed.
///
/// # Examples
/// ```rust
/// use sha2::{Sha256, Digest};
/// use keyfork_derive_util::VariableLengthSeed;
///
/// let data = b"the missile is very eepy and wants to take a small sleeb";
/// let seed = VariableLengthSeed::new(data);
/// ```
pub fn new(seed: &'a [u8]) -> Self {
Self { seed }
}
}
mod as_private_key {
use super::VariableLengthSeed;
pub trait AsPrivateKey {
fn as_private_key(&self) -> &[u8];
}
impl AsPrivateKey for [u8; 16] {
fn as_private_key(&self) -> &[u8] {
self
}
}
impl AsPrivateKey for [u8; 32] {
fn as_private_key(&self) -> &[u8] {
self
}
}
impl AsPrivateKey for [u8; 64] {
fn as_private_key(&self) -> &[u8] {
self
}
}
impl AsPrivateKey for VariableLengthSeed<'_> {
fn as_private_key(&self) -> &[u8] {
self.seed
}
}
}
/// Extended private keys derived using BIP-0032.
///
/// Generic over types implementing [`PrivateKey`].
@ -101,10 +163,10 @@ where
/// # };
/// let seed: &[u8; 64] = //
/// # b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
/// let xprv = ExtendedPrivateKey::<PrivateKey>::new(seed);
/// let xprv = ExtendedPrivateKey::<PrivateKey>::new(*seed);
/// ```
pub fn new(seed: impl AsRef<[u8]>) -> Self {
Self::new_internal(seed.as_ref())
pub fn new(seed: impl as_private_key::AsPrivateKey) -> Self {
Self::new_internal(seed.as_private_key())
}
fn new_internal(seed: &[u8]) -> Self {
@ -191,7 +253,7 @@ where
/// # 102, 201, 210, 159, 219, 222, 42, 201, 44, 196, 27,
/// # 90, 221, 80, 85, 135, 79, 39, 253, 223, 35, 251
/// # ];
/// let xprv = ExtendedPrivateKey::<PrivateKey>::new(seed);
/// let xprv = ExtendedPrivateKey::<PrivateKey>::new(*seed);
/// let xpub = xprv.extended_public_key();
/// assert_eq!(known_key, xpub.public_key().to_bytes());
/// # Ok(())
@ -215,7 +277,7 @@ where
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let seed: &[u8; 64] = //
/// # b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
/// let xprv = ExtendedPrivateKey::<PrivateKey>::new(seed);
/// let xprv = ExtendedPrivateKey::<PrivateKey>::new(*seed);
/// let pubkey = xprv.public_key();
/// # Ok(())
/// # }
@ -280,7 +342,7 @@ where
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let seed: &[u8; 64] = //
/// # b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
/// let root_xprv = ExtendedPrivateKey::<PrivateKey>::new(seed);
/// let root_xprv = ExtendedPrivateKey::<PrivateKey>::new(*seed);
/// let path = DerivationPath::default()
/// .chain_push(DerivationIndex::new(44, true)?)
/// .chain_push(DerivationIndex::new(0, true)?)
@ -326,7 +388,7 @@ where
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let seed: &[u8; 64] = //
/// # b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
/// let root_xprv = ExtendedPrivateKey::<PrivateKey>::new(seed);
/// let root_xprv = ExtendedPrivateKey::<PrivateKey>::new(*seed);
/// let bip44_wallet = DerivationPath::default()
/// .chain_push(DerivationIndex::new(44, true)?)
/// .chain_push(DerivationIndex::new(0, true)?)

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@ -17,7 +17,7 @@ pub mod public_key;
mod tests;
#[doc(inline)]
pub use crate::extended_key::{private_key::ExtendedPrivateKey, public_key::ExtendedPublicKey};
pub use crate::extended_key::{private_key::{ExtendedPrivateKey, Error as XPrvError, VariableLengthSeed}, public_key::{ExtendedPublicKey, Error as XPubError}};
pub use crate::{
index::{DerivationIndex, Error as IndexError},

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@ -19,10 +19,11 @@
//! ```
use crate::{
extended_key::private_key::Error as XPrvError,
extended_key::private_key::{Error as XPrvError, VariableLengthSeed},
private_key::{PrivateKey, TestPrivateKey},
DerivationPath, ExtendedPrivateKey,
};
use keyfork_mnemonic_util::{Mnemonic, MnemonicGenerationError};
use serde::{Deserialize, Serialize};
@ -64,7 +65,8 @@ impl DerivationAlgorithm {
///
/// # Errors
/// The method may error if the derivation fails or if the algorithm is not supported.
fn derive(&self, seed: Vec<u8>, path: &DerivationPath) -> Result<DerivationResponse> {
fn derive(&self, seed: &[u8], path: &DerivationPath) -> Result<DerivationResponse> {
let seed = VariableLengthSeed::new(seed);
match self {
#[cfg(feature = "ed25519")]
Self::Ed25519 => {
@ -207,7 +209,7 @@ impl DerivationRequest {
/// # }
pub fn derive_with_mnemonic(&self, mnemonic: &Mnemonic) -> Result<DerivationResponse> {
// TODO: passphrase support and/or store passphrase within mnemonic
self.derive_with_master_seed(mnemonic.seed(None)?)
self.derive_with_master_seed(&mnemonic.seed(None)?)
}
/// Derive an [`ExtendedPrivateKey`] using the given seed.
@ -231,10 +233,10 @@ impl DerivationRequest {
/// let path: DerivationPath = //
/// # DerivationPath::default();
/// let request = DerivationRequest::new(algo, &path);
/// let response = request.derive_with_master_seed(seed.to_vec())?;
/// let response = request.derive_with_master_seed(seed)?;
/// # Ok(())
/// # }
pub fn derive_with_master_seed(&self, seed: Vec<u8>) -> Result<DerivationResponse> {
pub fn derive_with_master_seed(&self, seed: &[u8]) -> Result<DerivationResponse> {
self.algorithm.derive(seed, &self.path)
}
}

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@ -30,7 +30,8 @@ fn secp256k1() {
} = test;
// Tests for ExtendedPrivateKey
let xkey = ExtendedPrivateKey::<SecretKey>::new(seed);
let varlen_seed = VariableLengthSeed::new(&seed);
let xkey = ExtendedPrivateKey::<SecretKey>::new(varlen_seed);
let derived_key = xkey.derive_path(&chain).unwrap();
assert_eq!(
derived_key.chain_code().as_slice(),
@ -50,7 +51,7 @@ fn secp256k1() {
// Tests for DerivationRequest
let request = DerivationRequest::new(DerivationAlgorithm::Secp256k1, &chain);
let response = request.derive_with_master_seed(seed.clone()).unwrap();
let response = request.derive_with_master_seed(&seed).unwrap();
assert_eq!(&response.data, private_key.as_slice(), "test: {chain}");
}
}
@ -75,7 +76,8 @@ fn ed25519() {
} = test;
// Tests for ExtendedPrivateKey
let xkey = ExtendedPrivateKey::<SigningKey>::new(seed);
let varlen_seed = VariableLengthSeed::new(&seed);
let xkey = ExtendedPrivateKey::<SigningKey>::new(varlen_seed);
let derived_key = xkey.derive_path(&chain).unwrap();
assert_eq!(
derived_key.chain_code().as_slice(),
@ -95,7 +97,7 @@ fn ed25519() {
// Tests for DerivationRequest
let request = DerivationRequest::new(DerivationAlgorithm::Ed25519, &chain);
let response = request.derive_with_master_seed(seed.to_vec()).unwrap();
let response = request.derive_with_master_seed(&seed).unwrap();
assert_eq!(&response.data, private_key.as_slice(), "test: {chain}");
}
}

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@ -7,11 +7,10 @@ license = "AGPL-3.0-only"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[features]
default = ["openpgp", "openpgp-card", "qrcode"]
default = ["openpgp", "openpgp-card", "qrcode", "sequoia-openpgp/crypto-nettle", "keyfork-qrcode/decode-backend-rqrr"]
openpgp = ["sequoia-openpgp", "anyhow"]
openpgp-card = ["openpgp-card-sequoia", "card-backend-pcsc", "card-backend", "dep:openpgp-card"]
qrcode = ["keyfork-qrcode"]
bin = ["sequoia-openpgp/crypto-nettle", "keyfork-qrcode/decode-backend-rqrr"]
[dependencies]
keyfork-prompt = { version = "0.1.0", path = "../util/keyfork-prompt", default-features = false, features = ["mnemonic"] }

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@ -14,7 +14,7 @@ use aes_gcm::{
};
use hkdf::{Hkdf, InvalidLength as HkdfInvalidLength};
use keyfork_derive_openpgp::{
derive_util::{DerivationPath, PathError},
derive_util::{DerivationPath, PathError, VariableLengthSeed},
XPrv,
};
use keyfork_mnemonic_util::{Mnemonic, MnemonicFromStrError, MnemonicGenerationError, Wordlist};
@ -648,7 +648,8 @@ pub fn combine(
// TODO: extract as function
let userid = UserID::from("keyfork-sss");
let path = DerivationPath::from_str("m/7366512'/0'")?;
let xprv = XPrv::new(&secret).derive_path(&path)?;
let seed = VariableLengthSeed::new(&secret);
let xprv = XPrv::new(seed).derive_path(&path)?;
let derived_cert = keyfork_derive_openpgp::derive(
xprv,
&[KeyFlags::empty().set_certification().set_signing()],
@ -679,10 +680,11 @@ pub fn combine(
/// The function may panic if the metadata can't properly store the certificates used to generate
/// the encrypted shares.
pub fn split(threshold: u8, certs: Vec<Cert>, secret: &[u8], output: impl Write) -> Result<()> {
let seed = VariableLengthSeed::new(secret);
// build cert to sign encrypted shares
let userid = UserID::from("keyfork-sss");
let path = DerivationPath::from_str("m/7366512'/0'")?;
let xprv = XPrv::new(&secret).derive_path(&path)?;
let xprv = XPrv::new(seed).derive_path(&path)?;
let derived_cert = keyfork_derive_openpgp::derive(
xprv,
&[KeyFlags::empty().set_certification().set_signing()],

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@ -21,7 +21,7 @@ pub struct PinLength(usize);
type Result<T, E = Box<dyn std::error::Error>> = std::result::Result<T, E>;
fn derive_key(seed: &[u8], index: u8) -> Result<Cert> {
fn derive_key(seed: [u8; 32], index: u8) -> Result<Cert> {
let subkeys = vec![
KeyFlags::empty().set_certification(),
KeyFlags::empty().set_signing(),
@ -102,7 +102,7 @@ fn generate_shard_secret(
keys_per_shard: u8,
output_file: &Option<PathBuf>,
) -> Result<()> {
let seed = keyfork_entropy::generate_entropy_of_size(256 / 8)?;
let seed = keyfork_entropy::generate_entropy_of_const_size::<{256 / 8}>()?;
let mut pm = Terminal::new(std::io::stdin(), std::io::stderr())?;
let mut certs = vec![];
let mut seen_cards: HashSet<String> = HashSet::new();
@ -126,7 +126,7 @@ fn generate_shard_secret(
.to_fn();
for index in 0..max {
let cert = derive_key(&seed, index)?;
let cert = derive_key(seed, index)?;
for i in 0..keys_per_shard {
pm.prompt_message(Message::Text(format!(
"Please remove all keys and insert key #{} for user #{}",

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@ -7,7 +7,7 @@ license = "MIT"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[features]
default = []
default = ["bin"]
bin = ["smex"]
[dependencies]

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@ -1,6 +1,9 @@
//! Utilities for reading entropy from secure sources.
use std::{fs::{read_dir, read_to_string, File}, io::Read};
use std::{
fs::{read_dir, read_to_string, File},
io::Read,
};
static WARNING_LINKS: [&str; 1] =
["https://lore.kernel.org/lkml/20211223141113.1240679-2-Jason@zx2c4.com/"];
@ -84,3 +87,24 @@ pub fn generate_entropy_of_size(byte_count: usize) -> Result<Vec<u8>, std::io::E
entropy_file.read_exact(&mut vec[..])?;
Ok(vec)
}
/// Read system entropy of a constant size.
///
/// # Errors
/// An error may be returned if an error occurred while reading from the random source.
///
/// # Examples
/// ```rust,no_run
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # std::env::set_var("SHOOT_SELF_IN_FOOT", "1");
/// let entropy = keyfork_entropy::generate_entropy_of_const_size::<64>()?;
/// assert_eq!(entropy.len(), 64);
/// # Ok(())
/// # }
/// ```
pub fn generate_entropy_of_const_size<const N: usize>() -> Result<[u8; N], std::io::Error> {
let mut output = [0u8; N];
let mut entropy_file = File::open("/dev/urandom")?;
entropy_file.read_exact(&mut output[..])?;
Ok(output)
}

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@ -7,7 +7,7 @@ edition = "2021"
license = "MIT"
[features]
default = []
default = ["bin"]
bin = ["smex"]
[dependencies]

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@ -276,7 +276,7 @@ impl Mnemonic {
}
/// Clone the existing entropy.
#[deprecated]
#[deprecated = "Use as_bytes(), to_bytes(), or into_bytes() instead"]
pub fn entropy(&self) -> Vec<u8> {
self.entropy.clone()
}
@ -353,8 +353,8 @@ mod tests {
random_handle.read_exact(&mut entropy[..]).unwrap();
let wordlist = Wordlist::default().arc();
let mnemonic = super::Mnemonic::from_entropy(&entropy[..256 / 8], wordlist).unwrap();
let new_entropy = mnemonic.entropy();
assert_eq!(&new_entropy, entropy);
let new_entropy = mnemonic.as_bytes();
assert_eq!(new_entropy, entropy);
}
#[test]

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@ -22,8 +22,8 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
3,
transport_validator.to_fn(),
)?;
assert_eq!(mnemonics[0].entropy().len(), 12);
assert_eq!(mnemonics[1].entropy().len(), 32);
assert_eq!(mnemonics[0].as_bytes().len(), 12);
assert_eq!(mnemonics[1].as_bytes().len(), 32);
let mnemonics = mgr.prompt_validated_wordlist(
"Enter a 24 and 48-word mnemonic: ",
@ -31,8 +31,8 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
3,
combine_validator.to_fn(),
)?;
assert_eq!(mnemonics[0].entropy().len(), 32);
assert_eq!(mnemonics[1].entropy().len(), 64);
assert_eq!(mnemonics[0].as_bytes().len(), 32);
assert_eq!(mnemonics[1].as_bytes().len(), 64);
Ok(())
}