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[keys] Add a way to restrict the networks in which keys are valid

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Thanks to the `ToWalletDescriptor` trait we can also very easily validate the checksum
for descriptors that are loaded from strings, if they contain one. Fixes #20.
This commit is contained in:
Alekos Filini
2020-09-21 15:44:07 +02:00
parent bc8acaf088
commit c51ba4a99f
8 changed files with 405 additions and 141 deletions
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253
src/keys/mod.rs
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@@ -25,36 +25,81 @@
//! Key formats
use std::any::TypeId;
use std::collections::HashSet;
use std::marker::PhantomData;
use bitcoin::util::bip32;
use bitcoin::{PrivateKey, PublicKey};
use bitcoin::{Network, PrivateKey, PublicKey};
use miniscript::descriptor::{DescriptorPublicKey, DescriptorSecretKey, DescriptorXKey, KeyMap};
pub use miniscript::ScriptContext;
use miniscript::{Miniscript, Terminal};
use crate::Error;
#[cfg(feature = "keys-bip39")]
#[cfg_attr(docsrs, doc(cfg(feature = "keys-bip39")))]
pub mod bip39;
/// Set of valid networks for a key
pub type ValidNetworks = HashSet<Network>;
/// Create a set containing mainnet, testnet and regtest
pub fn any_network() -> ValidNetworks {
vec![Network::Bitcoin, Network::Testnet, Network::Regtest]
.into_iter()
.collect()
}
/// Create a set only containing mainnet
pub fn mainnet_network() -> ValidNetworks {
vec![Network::Bitcoin].into_iter().collect()
}
/// Create a set containing testnet and regtest
pub fn test_networks() -> ValidNetworks {
vec![Network::Testnet, Network::Regtest]
.into_iter()
.collect()
}
/// Compute the intersection of two sets
pub fn merge_networks(a: &ValidNetworks, b: &ValidNetworks) -> ValidNetworks {
a.intersection(b).cloned().collect()
}
/// Container for public or secret keys
pub enum DescriptorKey<Ctx: ScriptContext> {
Public(DescriptorPublicKey, PhantomData<Ctx>),
Secret(DescriptorSecretKey, PhantomData<Ctx>),
#[doc(hidden)]
Public(DescriptorPublicKey, ValidNetworks, PhantomData<Ctx>),
#[doc(hidden)]
Secret(DescriptorSecretKey, ValidNetworks, PhantomData<Ctx>),
}
impl<Ctx: ScriptContext> DescriptorKey<Ctx> {
/// Create an instance given a public key and a set of valid networks
pub fn from_public(public: DescriptorPublicKey, networks: ValidNetworks) -> Self {
DescriptorKey::Public(public, networks, PhantomData)
}
/// Create an instance given a secret key and a set of valid networks
pub fn from_secret(secret: DescriptorSecretKey, networks: ValidNetworks) -> Self {
DescriptorKey::Secret(secret, networks, PhantomData)
}
/// Override the computed set of valid networks
pub fn override_valid_networks(self, networks: ValidNetworks) -> Self {
match self {
DescriptorKey::Public(key, _, _) => DescriptorKey::Public(key, networks, PhantomData),
DescriptorKey::Secret(key, _, _) => DescriptorKey::Secret(key, networks, PhantomData),
}
}
// This method is used internally by `bdk::fragment!` and `bdk::descriptor!`. It has to be
// public because it is effectively called by external crates, once the macros are expanded,
// but since it is not meant to be part of the public api we hide it from the docs.
#[doc(hidden)]
pub fn into_key_and_secret(self) -> Result<(DescriptorPublicKey, KeyMap), Error> {
pub fn extract(self) -> Result<(DescriptorPublicKey, KeyMap, ValidNetworks), KeyError> {
match self {
DescriptorKey::Public(public, _) => Ok((public, KeyMap::default())),
DescriptorKey::Secret(secret, _) => {
DescriptorKey::Public(public, valid_networks, _) => {
Ok((public, KeyMap::default(), valid_networks))
}
DescriptorKey::Secret(secret, valid_networks, _) => {
let mut key_map = KeyMap::with_capacity(1);
let public = secret
@@ -62,12 +107,13 @@ impl<Ctx: ScriptContext> DescriptorKey<Ctx> {
.map_err(|e| miniscript::Error::Unexpected(e.to_string()))?;
key_map.insert(public.clone(), secret);
Ok((public, key_map))
Ok((public, key_map, valid_networks))
}
}
}
}
/// Enum representation of the known valid [`ScriptContext`]s
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
pub enum ScriptContextEnum {
Legacy,
@@ -84,6 +130,7 @@ impl ScriptContextEnum {
}
}
/// Trait that adds extra useful methods to [`ScriptContext`]s
pub trait ExtScriptContext: ScriptContext {
fn as_enum() -> ScriptContextEnum;
@@ -116,7 +163,7 @@ impl<Ctx: ScriptContext + 'static> ExtScriptContext for Ctx {
/// For key types that do care about this, the [`ExtScriptContext`] trait provides some useful
/// methods that can be used to check at runtime which `Ctx` is being used.
///
/// For key types that that do not need to check this at runtime (because they can only work within a
/// For key types that can do this check statically (because they can only work within a
/// single `Ctx`), the "specialized" trait can be implemented to make the compiler handle the type
/// checking.
///
@@ -127,15 +174,14 @@ impl<Ctx: ScriptContext + 'static> ExtScriptContext for Ctx {
/// ```
/// use bdk::bitcoin::PublicKey;
///
/// use bdk::keys::{ScriptContext, ToDescriptorKey, DescriptorKey};
/// use bdk::Error;
/// use bdk::keys::{ScriptContext, ToDescriptorKey, DescriptorKey, KeyError};
///
/// pub struct MyKeyType {
/// pubkey: PublicKey,
/// }
///
/// impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for MyKeyType {
/// fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
/// fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
/// self.pubkey.to_descriptor_key()
/// }
/// }
@@ -146,8 +192,7 @@ impl<Ctx: ScriptContext + 'static> ExtScriptContext for Ctx {
/// ```
/// use bdk::bitcoin::PublicKey;
///
/// use bdk::keys::{ExtScriptContext, ScriptContext, ToDescriptorKey, DescriptorKey};
/// use bdk::Error;
/// use bdk::keys::{ExtScriptContext, ScriptContext, ToDescriptorKey, DescriptorKey, KeyError};
///
/// pub struct MyKeyType {
/// is_legacy: bool,
@@ -155,11 +200,11 @@ impl<Ctx: ScriptContext + 'static> ExtScriptContext for Ctx {
/// }
///
/// impl<Ctx: ScriptContext + 'static> ToDescriptorKey<Ctx> for MyKeyType {
/// fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
/// fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
/// if Ctx::is_legacy() == self.is_legacy {
/// self.pubkey.to_descriptor_key()
/// } else {
/// Err(Error::Generic("Invalid key context".into()))
/// Err(KeyError::InvalidScriptContext)
/// }
/// }
/// }
@@ -176,15 +221,14 @@ impl<Ctx: ScriptContext + 'static> ExtScriptContext for Ctx {
/// use std::str::FromStr;
/// use bdk::bitcoin::PublicKey;
///
/// use bdk::keys::{ToDescriptorKey, DescriptorKey};
/// use bdk::Error;
/// use bdk::keys::{ToDescriptorKey, DescriptorKey, KeyError};
///
/// pub struct MySegwitOnlyKeyType {
/// pubkey: PublicKey,
/// }
///
/// impl ToDescriptorKey<bdk::miniscript::Segwitv0> for MySegwitOnlyKeyType {
/// fn to_descriptor_key(self) -> Result<DescriptorKey<bdk::miniscript::Segwitv0>, Error> {
/// fn to_descriptor_key(self) -> Result<DescriptorKey<bdk::miniscript::Segwitv0>, KeyError> {
/// self.pubkey.to_descriptor_key()
/// }
/// }
@@ -192,25 +236,28 @@ impl<Ctx: ScriptContext + 'static> ExtScriptContext for Ctx {
/// let key = MySegwitOnlyKeyType {
/// pubkey: PublicKey::from_str("...")?,
/// };
/// let (descriptor, _) = bdk::descriptor!(pkh ( key ) )?;
/// // ^^^^^ changing this to `wpkh` would make it compile
/// let (descriptor, _, _) = bdk::descriptor!(pkh ( key ) )?;
/// // ^^^^^ changing this to `wpkh` would make it compile
///
/// # Ok::<_, Box<dyn std::error::Error>>(())
/// ```
pub trait ToDescriptorKey<Ctx: ScriptContext>: Sized {
/// Turn the key into a [`DescriptorKey`] within the requested [`ScriptContext`]
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error>;
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError>;
}
// Used internally by `bdk::fragment!` to build `pk_k()` fragments
#[doc(hidden)]
fn into_miniscript_and_secret(
self,
) -> Result<(Miniscript<DescriptorPublicKey, Ctx>, KeyMap), Error> {
let descriptor_key = self.to_descriptor_key()?;
let (key, key_map) = descriptor_key.into_key_and_secret()?;
// Used internally by `bdk::fragment!` to build `pk_k()` fragments
#[doc(hidden)]
pub fn make_pk<Pk: ToDescriptorKey<Ctx>, Ctx: ScriptContext>(
descriptor_key: Pk,
) -> Result<(Miniscript<DescriptorPublicKey, Ctx>, KeyMap, ValidNetworks), KeyError> {
let (key, key_map, valid_networks) = descriptor_key.to_descriptor_key()?.extract()?;
Ok((Miniscript::from_ast(Terminal::PkK(key))?, key_map))
}
Ok((
Miniscript::from_ast(Terminal::PkK(key))?,
key_map,
valid_networks,
))
}
// Used internally by `bdk::fragment!` to build `multi()` fragments
@@ -218,90 +265,136 @@ pub trait ToDescriptorKey<Ctx: ScriptContext>: Sized {
pub fn make_multi<Pk: ToDescriptorKey<Ctx>, Ctx: ScriptContext>(
thresh: usize,
pks: Vec<Pk>,
) -> Result<(Miniscript<DescriptorPublicKey, Ctx>, KeyMap), Error> {
let (pks, key_maps): (Vec<_>, Vec<_>) = pks
) -> Result<(Miniscript<DescriptorPublicKey, Ctx>, KeyMap, ValidNetworks), KeyError> {
let (pks, key_maps_networks): (Vec<_>, Vec<_>) = pks
.into_iter()
.map(|key| {
key.to_descriptor_key()
.and_then(DescriptorKey::into_key_and_secret)
})
.map(|key| Ok::<_, KeyError>(key.to_descriptor_key()?.extract()?))
.collect::<Result<Vec<_>, _>>()?
.into_iter()
.map(|(a, b, c)| (a, (b, c)))
.unzip();
let key_map = key_maps
.into_iter()
.fold(KeyMap::default(), |mut acc, map| {
acc.extend(map.into_iter());
acc
});
let (key_map, valid_networks) = key_maps_networks.into_iter().fold(
(KeyMap::default(), any_network()),
|(mut keys_acc, net_acc), (key, net)| {
keys_acc.extend(key.into_iter());
let net_acc = merge_networks(&net_acc, &net);
Ok((Miniscript::from_ast(Terminal::Multi(thresh, pks))?, key_map))
(keys_acc, net_acc)
},
);
Ok((
Miniscript::from_ast(Terminal::Multi(thresh, pks))?,
key_map,
valid_networks,
))
}
/// The "identity" conversion is used internally by some `bdk::fragment`s
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for DescriptorKey<Ctx> {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
Ok(self)
}
}
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for DescriptorPublicKey {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
Ok(DescriptorKey::Public(self, PhantomData))
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
let networks = match self {
DescriptorPublicKey::PubKey(_) => any_network(),
DescriptorPublicKey::XPub(DescriptorXKey { xkey, .. })
if xkey.network == Network::Bitcoin =>
{
mainnet_network()
}
_ => test_networks(),
};
Ok(DescriptorKey::from_public(self, networks))
}
}
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for PublicKey {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
Ok(DescriptorKey::Public(
DescriptorPublicKey::PubKey(self),
PhantomData,
))
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
DescriptorPublicKey::PubKey(self).to_descriptor_key()
}
}
/// This assumes that "is_wildcard" is true, since this is generally the way extended keys are used
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for (bip32::ExtendedPubKey, bip32::DerivationPath) {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
Ok(DescriptorKey::Public(
DescriptorPublicKey::XPub(DescriptorXKey {
source: None,
xkey: self.0,
derivation_path: self.1,
is_wildcard: true,
}),
PhantomData,
))
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
DescriptorPublicKey::XPub(DescriptorXKey {
source: None,
xkey: self.0,
derivation_path: self.1,
is_wildcard: true,
})
.to_descriptor_key()
}
}
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for DescriptorSecretKey {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
Ok(DescriptorKey::Secret(self, PhantomData))
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
let networks = match self {
DescriptorSecretKey::PrivKey(sk) if sk.network == Network::Bitcoin => mainnet_network(),
DescriptorSecretKey::XPrv(DescriptorXKey { xkey, .. })
if xkey.network == Network::Bitcoin =>
{
mainnet_network()
}
_ => test_networks(),
};
Ok(DescriptorKey::from_secret(self, networks))
}
}
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for PrivateKey {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
Ok(DescriptorKey::Secret(
DescriptorSecretKey::PrivKey(self),
PhantomData,
))
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
DescriptorSecretKey::PrivKey(self).to_descriptor_key()
}
}
/// This assumes that "is_wildcard" is true, since this is generally the way extended keys are used
impl<Ctx: ScriptContext> ToDescriptorKey<Ctx> for (bip32::ExtendedPrivKey, bip32::DerivationPath) {
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, Error> {
Ok(DescriptorKey::Secret(
DescriptorSecretKey::XPrv(DescriptorXKey {
source: None,
xkey: self.0,
derivation_path: self.1,
is_wildcard: true,
}),
PhantomData,
))
fn to_descriptor_key(self) -> Result<DescriptorKey<Ctx>, KeyError> {
DescriptorSecretKey::XPrv(DescriptorXKey {
source: None,
xkey: self.0,
derivation_path: self.1,
is_wildcard: true,
})
.to_descriptor_key()
}
}
#[derive(Debug)]
pub enum KeyError {
InvalidScriptContext,
InvalidNetwork,
InvalidChecksum,
Message(String),
BIP32(bitcoin::util::bip32::Error),
Miniscript(miniscript::Error),
}
impl From<miniscript::Error> for KeyError {
fn from(inner: miniscript::Error) -> Self {
KeyError::Miniscript(inner)
}
}
impl From<bitcoin::util::bip32::Error> for KeyError {
fn from(inner: bitcoin::util::bip32::Error) -> Self {
KeyError::BIP32(inner)
}
}
impl std::fmt::Display for KeyError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "{:?}", self)
}
}
impl std::error::Error for KeyError {}