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Merge pull request #253 from apoelstra/2020-11--schnorrsig-followup 

BIP 0340 followups
This commit is contained in:
Andrew Poelstra 2020-12-09 20:31:07 +00:00 committed by GitHub
parent be9a78f39e ea027ce258
commit 11e9641d21
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 187 additions and 85 deletions
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132
secp256k1-sys/src/lib.rs
View File

@ -106,13 +106,32 @@ impl_array_newtype!(PublicKey, c_uchar, 64);
impl_raw_debug!(PublicKey);
impl PublicKey {
/// Create a new (zeroed) public key usable for the FFI interface
pub fn new() -> PublicKey { PublicKey([0; 64]) }
}
/// Creates an "uninitialized" FFI public key which is zeroed out
///
/// If you pass this to any FFI functions, except as an out-pointer,
/// the result is likely to be an assertation failure and process
/// termination.
pub unsafe fn new() -> Self {
Self::from_array_unchecked([0; 64])
}
impl Default for PublicKey {
fn default() -> Self {
PublicKey::new()
/// Create a new public key usable for the FFI interface from raw bytes
///
/// Does not check the validity of the underlying representation. If it is
/// invalid the result may be assertation failures (and process aborts) from
/// the underlying library. You should not use this method except with data
/// that you obtained from the FFI interface of the same version of this
/// library.
pub unsafe fn from_array_unchecked(data: [c_uchar; 64]) -> Self {
PublicKey(data)
}
/// Returns the underlying FFI opaque representation of the public key
///
/// You should not use this unless you really know what you are doing. It is
/// essentially only useful for extending the FFI interface itself.
pub fn underlying_bytes(self) -> [c_uchar; 64] {
self.0
}
}
@ -129,13 +148,32 @@ impl_array_newtype!(Signature, c_uchar, 64);
impl_raw_debug!(Signature);
impl Signature {
/// Create a new (zeroed) signature usable for the FFI interface
pub fn new() -> Signature { Signature([0; 64]) }
}
/// Creates an "uninitialized" FFI signature which is zeroed out
///
/// If you pass this to any FFI functions, except as an out-pointer,
/// the result is likely to be an assertation failure and process
/// termination.
pub unsafe fn new() -> Self {
Self::from_array_unchecked([0; 64])
}
impl Default for Signature {
fn default() -> Self {
Signature::new()
/// Create a new signature usable for the FFI interface from raw bytes
///
/// Does not check the validity of the underlying representation. If it is
/// invalid the result may be assertation failures (and process aborts) from
/// the underlying library. You should not use this method except with data
/// that you obtained from the FFI interface of the same version of this
/// library.
pub unsafe fn from_array_unchecked(data: [c_uchar; 64]) -> Self {
Signature(data)
}
/// Returns the underlying FFI opaque representation of the signature
///
/// You should not use this unless you really know what you are doing. It is
/// essentially only useful for extending the FFI interface itself.
pub fn underlying_bytes(self) -> [c_uchar; 64] {
self.0
}
}
@ -145,11 +183,33 @@ impl_array_newtype!(XOnlyPublicKey, c_uchar, 64);
impl_raw_debug!(XOnlyPublicKey);
impl XOnlyPublicKey {
/// Create a new (zeroed) x-only public key usable for the FFI interface
pub fn new() -> XOnlyPublicKey { XOnlyPublicKey([0; 64]) }
pub fn from_array(data: [c_uchar; 64]) -> XOnlyPublicKey {
/// Creates an "uninitialized" FFI x-only public key which is zeroed out
///
/// If you pass this to any FFI functions, except as an out-pointer,
/// the result is likely to be an assertation failure and process
/// termination.
pub unsafe fn new() -> Self {
Self::from_array_unchecked([0; 64])
}
/// Create a new x-only public key usable for the FFI interface from raw bytes
///
/// Does not check the validity of the underlying representation. If it is
/// invalid the result may be assertation failures (and process aborts) from
/// the underlying library. You should not use this method except with data
/// that you obtained from the FFI interface of the same version of this
/// library.
pub unsafe fn from_array_unchecked(data: [c_uchar; 64]) -> Self {
XOnlyPublicKey(data)
}
/// Returns the underlying FFI opaque representation of the x-only public key
///
/// You should not use this unless you really know what you are doing. It is
/// essentially only useful for extending the FFI interface itself.
pub fn underlying_bytes(self) -> [c_uchar; 64] {
self.0
}
}
impl hash::Hash for XOnlyPublicKey {
@ -158,23 +218,39 @@ impl hash::Hash for XOnlyPublicKey {
}
}
impl Default for XOnlyPublicKey {
fn default() -> Self {
XOnlyPublicKey::new()
}
}
#[repr(C)]
pub struct KeyPair([c_uchar; 96]);
impl_array_newtype!(KeyPair, c_uchar, 96);
impl_raw_debug!(KeyPair);
impl KeyPair {
/// Create a new (zeroed) key pair usable for the FFI interface
pub fn new() -> KeyPair { KeyPair([0; 96]) }
pub fn from_array(data: [c_uchar; 96]) -> KeyPair {
/// Creates an "uninitialized" FFI keypair which is zeroed out
///
/// If you pass this to any FFI functions, except as an out-pointer,
/// the result is likely to be an assertation failure and process
/// termination.
pub unsafe fn new() -> Self {
Self::from_array_unchecked([0; 96])
}
/// Create a new keypair usable for the FFI interface from raw bytes
///
/// Does not check the validity of the underlying representation. If it is
/// invalid the result may be assertation failures (and process aborts) from
/// the underlying library. You should not use this method except with data
/// that you obtained from the FFI interface of the same version of this
/// library.
pub unsafe fn from_array_unchecked(data: [c_uchar; 96]) -> Self {
KeyPair(data)
}
/// Returns the underlying FFI opaque representation of the x-only public key
///
/// You should not use this unless you really know what you are doing. It is
/// essentially only useful for extending the FFI interface itself.
pub fn underlying_bytes(self) -> [c_uchar; 96] {
self.0
}
}
impl hash::Hash for KeyPair {
@ -183,12 +259,6 @@ impl hash::Hash for KeyPair {
}
}
impl Default for KeyPair {
fn default() -> Self {
KeyPair::new()
}
}
#[cfg(not(feature = "fuzztarget"))]
extern "C" {
/// Default ECDH hash function
@ -591,7 +661,7 @@ impl<T> CPtr for [T] {
fn as_mut_c_ptr(&mut self) -> *mut Self::Target {
if self.is_empty() {
ptr::null::<Self::Target>() as *mut _
ptr::null_mut::<Self::Target>()
} else {
self.as_mut_ptr()
}

18
src/key.rs
View File

@ -219,13 +219,13 @@ impl PublicKey {
/// Obtains a raw const pointer suitable for use with FFI functions
#[inline]
pub fn as_ptr(&self) -> *const ffi::PublicKey {
&self.0 as *const _
&self.0
}
/// Obtains a raw mutable pointer suitable for use with FFI functions
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut ffi::PublicKey {
&mut self.0 as *mut _
&mut self.0
}
/// Creates a new public key from a secret key.
@ -233,23 +233,23 @@ impl PublicKey {
pub fn from_secret_key<C: Signing>(secp: &Secp256k1<C>,
sk: &SecretKey)
-> PublicKey {
let mut pk = ffi::PublicKey::new();
unsafe {
let mut pk = ffi::PublicKey::new();
// We can assume the return value because it's not possible to construct
// an invalid `SecretKey` without transmute trickery or something
let res = ffi::secp256k1_ec_pubkey_create(secp.ctx, &mut pk, sk.as_c_ptr());
debug_assert_eq!(res, 1);
}
PublicKey(pk)
}
}
/// Creates a public key directly from a slice
#[inline]
pub fn from_slice(data: &[u8]) -> Result<PublicKey, Error> {
if data.is_empty() {return Err(Error::InvalidPublicKey);}
let mut pk = ffi::PublicKey::new();
unsafe {
let mut pk = ffi::PublicKey::new();
if ffi::secp256k1_ec_pubkey_parse(
ffi::secp256k1_context_no_precomp,
&mut pk,
@ -313,7 +313,7 @@ impl PublicKey {
secp: &Secp256k1<C>
) {
unsafe {
let res = ffi::secp256k1_ec_pubkey_negate(secp.ctx, &mut self.0 as *mut _);
let res = ffi::secp256k1_ec_pubkey_negate(secp.ctx, &mut self.0);
debug_assert_eq!(res, 1);
}
}
@ -331,8 +331,7 @@ impl PublicKey {
return Err(Error::InvalidTweak);
}
unsafe {
if ffi::secp256k1_ec_pubkey_tweak_add(secp.ctx, &mut self.0 as *mut _,
other.as_c_ptr()) == 1 {
if ffi::secp256k1_ec_pubkey_tweak_add(secp.ctx, &mut self.0, other.as_c_ptr()) == 1 {
Ok(())
} else {
Err(Error::InvalidTweak)
@ -353,8 +352,7 @@ impl PublicKey {
return Err(Error::InvalidTweak);
}
unsafe {
if ffi::secp256k1_ec_pubkey_tweak_mul(secp.ctx, &mut self.0 as *mut _,
other.as_c_ptr()) == 1 {
if ffi::secp256k1_ec_pubkey_tweak_mul(secp.ctx, &mut self.0, other.as_c_ptr()) == 1 {
Ok(())
} else {
Err(Error::InvalidTweak)

17
src/lib.rs
View File

@ -269,9 +269,8 @@ impl Signature {
pub fn from_der(data: &[u8]) -> Result<Signature, Error> {
if data.is_empty() {return Err(Error::InvalidSignature);}
let mut ret = ffi::Signature::new();
unsafe {
let mut ret = ffi::Signature::new();
if ffi::secp256k1_ecdsa_signature_parse_der(
ffi::secp256k1_context_no_precomp,
&mut ret,
@ -288,12 +287,12 @@ impl Signature {
/// Converts a 64-byte compact-encoded byte slice to a signature
pub fn from_compact(data: &[u8]) -> Result<Signature, Error> {
let mut ret = ffi::Signature::new();
if data.len() != 64 {
return Err(Error::InvalidSignature)
}
unsafe {
let mut ret = ffi::Signature::new();
if ffi::secp256k1_ecdsa_signature_parse_compact(
ffi::secp256k1_context_no_precomp,
&mut ret,
@ -362,13 +361,13 @@ impl Signature {
/// Obtains a raw pointer suitable for use with FFI functions
#[inline]
pub fn as_ptr(&self) -> *const ffi::Signature {
&self.0 as *const _
&self.0
}
/// Obtains a raw mutable pointer suitable for use with FFI functions
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut ffi::Signature {
&mut self.0 as *mut _
&mut self.0
}
#[inline]
@ -522,6 +521,8 @@ pub enum Error {
InvalidRecoveryId,
/// Invalid tweak for add_*_assign or mul_*_assign
InvalidTweak,
/// `tweak_add_check` failed on an xonly public key
TweakCheckFailed,
/// Didn't pass enough memory to context creation with preallocated memory
NotEnoughMemory,
}
@ -536,6 +537,7 @@ impl Error {
Error::InvalidSecretKey => "secp: malformed or out-of-range secret key",
Error::InvalidRecoveryId => "secp: bad recovery id",
Error::InvalidTweak => "secp: bad tweak",
Error::TweakCheckFailed => "secp: xonly_pubkey_tewak_add_check failed",
Error::NotEnoughMemory => "secp: not enough memory allocated",
}
}
@ -661,17 +663,16 @@ impl<C: Signing> Secp256k1<C> {
pub fn sign(&self, msg: &Message, sk: &key::SecretKey)
-> Signature {
let mut ret = ffi::Signature::new();
unsafe {
let mut ret = ffi::Signature::new();
// We can assume the return value because it's not possible to construct
// an invalid signature from a valid `Message` and `SecretKey`
assert_eq!(ffi::secp256k1_ecdsa_sign(self.ctx, &mut ret, msg.as_c_ptr(),
sk.as_c_ptr(), ffi::secp256k1_nonce_function_rfc6979,
ptr::null()), 1);
}
Signature::from(ret)
}
}
/// Generates a random keypair. Convenience function for `key::SecretKey::new`
/// and `key::PublicKey::from_secret_key`; call those functions directly for

13
src/recovery.rs
View File

@ -82,13 +82,13 @@ impl RecoverableSignature {
/// Obtains a raw pointer suitable for use with FFI functions
#[inline]
pub fn as_ptr(&self) -> *const ffi::RecoverableSignature {
&self.0 as *const _
&self.0
}
/// Obtains a raw mutable pointer suitable for use with FFI functions
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut ffi::RecoverableSignature {
&mut self.0 as *mut _
&mut self.0
}
#[inline]
@ -112,17 +112,17 @@ impl RecoverableSignature {
/// for verification
#[inline]
pub fn to_standard(&self) -> Signature {
let mut ret = super_ffi::Signature::new();
unsafe {
let mut ret = super_ffi::Signature::new();
let err = ffi::secp256k1_ecdsa_recoverable_signature_convert(
super_ffi::secp256k1_context_no_precomp,
&mut ret,
self.as_c_ptr(),
);
assert!(err == 1);
}
Signature(ret)
}
}
}
@ -178,16 +178,15 @@ impl<C: Verification> Secp256k1<C> {
pub fn recover(&self, msg: &Message, sig: &RecoverableSignature)
-> Result<key::PublicKey, Error> {
let mut pk = super_ffi::PublicKey::new();
unsafe {
let mut pk = super_ffi::PublicKey::new();
if ffi::secp256k1_ecdsa_recover(self.ctx, &mut pk,
sig.as_c_ptr(), msg.as_c_ptr()) != 1 {
return Err(Error::InvalidSignature);
}
};
Ok(key::PublicKey::from(pk))
}
}
}

90
src/schnorrsig.rs
View File

@ -104,13 +104,13 @@ impl KeyPair {
/// Obtains a raw const pointer suitable for use with FFI functions
#[inline]
pub fn as_ptr(&self) -> *const ffi::KeyPair {
&self.0 as *const _
&self.0
}
/// Obtains a raw mutable pointer suitable for use with FFI functions
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut ffi::KeyPair {
&mut self.0 as *mut _
&mut self.0
}
/// Creates a Schnorr KeyPair directly from a secret key slice
@ -123,8 +123,8 @@ impl KeyPair {
return Err(InvalidPublicKey);
}
let mut kp = ffi::KeyPair::new();
unsafe {
let mut kp = ffi::KeyPair::new();
if ffi::secp256k1_keypair_create(secp.ctx, &mut kp, data.as_c_ptr()) == 1 {
Ok(KeyPair(kp))
} else {
@ -155,21 +155,21 @@ impl KeyPair {
ret
};
let mut data = random_32_bytes();
let mut keypair = ffi::KeyPair::new();
unsafe {
let mut keypair = ffi::KeyPair::new();
while ffi::secp256k1_keypair_create(secp.ctx, &mut keypair, data.as_c_ptr()) == 0 {
data = random_32_bytes();
}
}
KeyPair(keypair)
}
}
/// Tweak a keypair by adding the given tweak to the secret key and updating the
/// public key accordingly.
/// Will return an error if the resulting key would be invalid or if
/// the tweak was not a 32-byte length slice.
#[inline]
pub fn add_assign<C: Verification>(
pub fn tweak_add_assign<C: Verification>(
&mut self,
secp: &Secp256k1<C>,
tweak: &[u8],
@ -181,7 +181,7 @@ impl KeyPair {
unsafe {
let err = ffi::secp256k1_keypair_xonly_tweak_add(
secp.ctx,
&mut self.0 as *mut _,
&mut self.0,
tweak.as_c_ptr(),
);
@ -198,21 +198,21 @@ impl PublicKey {
/// Obtains a raw const pointer suitable for use with FFI functions
#[inline]
pub fn as_ptr(&self) -> *const ffi::XOnlyPublicKey {
&self.0 as *const _
&self.0
}
/// Obtains a raw mutable pointer suitable for use with FFI functions
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut ffi::XOnlyPublicKey {
&mut self.0 as *mut _
&mut self.0
}
/// Creates a new Schnorr public key from a Schnorr key pair
#[inline]
pub fn from_keypair<C: Signing>(secp: &Secp256k1<C>, keypair: &KeyPair) -> PublicKey {
let mut xonly_pk = ffi::XOnlyPublicKey::new();
let mut pk_parity = 0;
unsafe {
let mut xonly_pk = ffi::XOnlyPublicKey::new();
let ret = ffi::secp256k1_keypair_xonly_pub(
secp.ctx,
&mut xonly_pk,
@ -220,9 +220,9 @@ impl PublicKey {
keypair.as_ptr(),
);
debug_assert_eq!(ret, 1);
}
PublicKey(xonly_pk)
}
}
/// Creates a Schnorr public key directly from a slice
#[inline]
@ -231,8 +231,8 @@ impl PublicKey {
return Err(InvalidPublicKey);
}
let mut pk = ffi::XOnlyPublicKey::new();
unsafe {
let mut pk = ffi::XOnlyPublicKey::new();
if ffi::secp256k1_xonly_pubkey_parse(
ffi::secp256k1_context_no_precomp,
&mut pk,
@ -264,14 +264,17 @@ impl PublicKey {
ret
}
/// Tweak a schnorrsig PublicKey by adding the generator multiplied with the given tweak to it.
/// Will return an error if the resulting key would be invalid or if
/// the tweak was not a 32-byte length slice.
pub fn add_assign<V: Verification>(
/// Tweak an x-only PublicKey by adding the generator multiplied with the given tweak to it.
///
/// Returns a boolean representing the parity of the tweaked key, which can be provided to
/// `tweak_add_check` which can be used to verify a tweak more efficiently than regenerating
/// it and checking equality. Will return an error if the resulting key would be invalid or
/// if the tweak was not a 32-byte length slice.
pub fn tweak_add_assign<V: Verification>(
&mut self,
secp: &Secp256k1<V>,
tweak: &[u8],
) -> Result<(), Error> {
) -> Result<bool, Error> {
if tweak.len() != 32 {
return Err(Error::InvalidTweak);
}
@ -289,18 +292,49 @@ impl PublicKey {
return Err(Error::InvalidTweak);
}
let mut parity: ::secp256k1_sys::types::c_int = 0;
err = ffi::secp256k1_xonly_pubkey_from_pubkey(
secp.ctx,
&mut self.0 as *mut _,
ptr::null_mut(),
&mut self.0,
&mut parity,
&pubkey,
);
return if err == 0 {
if err == 0 {
Err(Error::InvalidPublicKey)
} else {
Ok(())
};
Ok(parity != 0)
}
}
}
/// Verify that a tweak produced by `tweak_add_assign` was computed correctly
///
/// Should be called on the original untweaked key. Takes the tweaked key and
/// output parity from `tweak_add_assign` as input.
///
/// Currently this is not much more efficient than just recomputing the tweak
/// and checking equality. However, in future this API will support batch
/// verification, which is significantly faster, so it is wise to design
/// protocols with this in mind.
pub fn tweak_add_check<V: Verification>(
&self,
secp: &Secp256k1<V>,
tweaked_key: &Self,
tweaked_parity: bool,
tweak: [u8; 32],
) -> bool {
let tweaked_ser = tweaked_key.serialize();
unsafe {
let err = ffi::secp256k1_xonly_pubkey_tweak_add_check(
secp.ctx,
tweaked_ser.as_c_ptr(),
if tweaked_parity { 1 } else { 0 },
&self.0,
tweak.as_c_ptr(),
);
err == 1
}
}
}
@ -326,9 +360,8 @@ impl From<ffi::XOnlyPublicKey> for PublicKey {
impl From<::key::PublicKey> for PublicKey {
fn from(src: ::key::PublicKey) -> PublicKey {
let mut pk = ffi::XOnlyPublicKey::new();
unsafe {
let mut pk = ffi::XOnlyPublicKey::new();
assert_eq!(
1,
ffi::secp256k1_xonly_pubkey_from_pubkey(
@ -338,10 +371,9 @@ impl From<::key::PublicKey> for PublicKey {
src.as_c_ptr(),
)
);
}
PublicKey(pk)
}
}
}
serde_impl_from_slice!(PublicKey);
@ -722,9 +754,11 @@ mod tests {
let mut tweak = [0u8; 32];
thread_rng().fill_bytes(&mut tweak);
let (mut kp, mut pk) = s.generate_schnorrsig_keypair(&mut thread_rng());
kp.add_assign(&s, &tweak).expect("Tweak error");
pk.add_assign(&s, &tweak).expect("Tweak error");
let orig_pk = pk;
kp.tweak_add_assign(&s, &tweak).expect("Tweak error");
let parity = pk.tweak_add_assign(&s, &tweak).expect("Tweak error");
assert_eq!(PublicKey::from_keypair(&s, &kp), pk);
assert!(orig_pk.tweak_add_check(&s, &pk, parity, tweak));
}
}