Add MessageSignature type for dealing with signed messages

This commit is contained in:
Steven Roose 2020-10-07 17:46:48 +02:00
parent 926cff0741
commit f7422fb8d1
No known key found for this signature in database
GPG Key ID: 2F2A88D7F8D68E87
4 changed files with 219 additions and 5 deletions

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@ -12,18 +12,21 @@ readme = "README.md"
[features]
default = [ "secp-recovery" ]
base64 = [ "base64-compat" ]
fuzztarget = ["secp256k1/fuzztarget", "bitcoin_hashes/fuzztarget"]
unstable = []
rand = ["secp256k1/rand-std"]
use-serde = ["serde", "bitcoin_hashes/serde", "secp256k1/serde"]
secp-recovery = ["secp256k1/recovery"]
secp-endomorphism = ["secp256k1/endomorphism"]
secp-lowmemory = ["secp256k1/lowmemory"]
secp-recovery = ["secp256k1/recovery"]
[dependencies]
base64-compat = { version = "1.0.0", optional = true }
bech32 = "0.7.2"
bitcoin_hashes = "0.9.0"
secp256k1 = "0.19.0"
secp256k1 = { version = "0.19.0", features = [ "recovery" ] }
bitcoinconsensus = { version = "0.19.0-1", optional = true }
serde = { version = "1", optional = true }
@ -32,6 +35,6 @@ serde = { version = "1", optional = true }
serde_derive = "<1.0.99"
serde_json = "<1.0.45"
serde_test = "1"
secp256k1 = { version = "0.19.0", features = ["rand-std"] }
secp256k1 = { version = "0.19.0", features = [ "recovery", "rand-std" ] }
# We need to pin ryu (transitive dep from serde_json) to stay compatible with Rust 1.22.0
ryu = "<1.0.5"

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@ -1,6 +1,6 @@
#!/bin/sh -ex
FEATURES="bitcoinconsensus use-serde rand"
FEATURES="base64 bitcoinconsensus use-serde rand"
if [ "$DO_COV" = true ]
then
@ -15,6 +15,8 @@ then
fi
# Test without any features first
cargo test --verbose --no-default-features
# Then test with the default features
cargo test --verbose
# Test each feature

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@ -40,6 +40,7 @@
#[macro_use] pub extern crate bitcoin_hashes as hashes;
pub extern crate secp256k1;
pub extern crate bech32;
#[cfg(feature = "base64")] pub extern crate base64;
#[cfg(feature="bitcoinconsensus")] extern crate bitcoinconsensus;
#[cfg(feature = "serde")] extern crate serde;

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@ -17,11 +17,188 @@
//! Various utility functions
use hashes::{sha256d, Hash, HashEngine};
use blockdata::opcodes;
use consensus::{encode, Encodable};
#[cfg(feature = "secp-recovery")]
pub use self::message_signing::{MessageSignature, MessageSignatureError};
static MSG_SIGN_PREFIX: &[u8] = b"\x18Bitcoin Signed Message:\n";
#[cfg(feature = "secp-recovery")]
mod message_signing {
use std::{error, fmt};
use hashes::sha256d;
use secp256k1;
use secp256k1::recovery::{RecoveryId, RecoverableSignature};
use util::key::PublicKey;
use util::address::{Address, AddressType};
/// An error used for dealing with Bitcoin Signed Messages.
#[derive(Debug, PartialEq, Eq)]
pub enum MessageSignatureError {
/// Signature is expected to be 65 bytes.
InvalidLength,
/// The signature is invalidly constructed.
InvalidEncoding(secp256k1::Error),
/// Invalid base64 encoding.
InvalidBase64,
}
impl fmt::Display for MessageSignatureError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
MessageSignatureError::InvalidLength => write!(f, "length not 65 bytes"),
MessageSignatureError::InvalidEncoding(ref e) => write!(f, "invalid encoding: {}", e),
MessageSignatureError::InvalidBase64 => write!(f, "invalid base64"),
}
}
}
impl error::Error for MessageSignatureError {
fn cause(&self) -> Option<&dyn error::Error> {
match *self {
MessageSignatureError::InvalidEncoding(ref e) => Some(e),
_ => None,
}
}
}
#[doc(hidden)]
impl From<secp256k1::Error> for MessageSignatureError {
fn from(e: secp256k1::Error) -> MessageSignatureError {
MessageSignatureError::InvalidEncoding(e)
}
}
/// A signature on a Bitcoin Signed Message.
///
/// In order to use the `to_base64` and `from_base64` methods, as well as the
/// `fmt::Display` and `str::FromStr` implementations, the `base64` feature
/// must be enabled.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub struct MessageSignature {
/// The inner recoverable signature.
pub signature: RecoverableSignature,
/// Whether or not this signature was created with a compressed key.
pub compressed: bool,
}
impl MessageSignature {
/// Create a new [MessageSignature].
pub fn new(signature: RecoverableSignature, compressed: bool) -> MessageSignature {
MessageSignature {
signature: signature,
compressed: compressed,
}
}
/// Serialize to bytes.
pub fn serialize(&self) -> [u8; 65] {
let (recid, raw) = self.signature.serialize_compact();
let mut serialized = [0u8; 65];
serialized[0] = 27;
serialized[0] += recid.to_i32() as u8;
if self.compressed {
serialized[0] += 4;
}
serialized[1..].copy_from_slice(&raw[..]);
serialized
}
/// Create from a byte slice.
pub fn from_slice(bytes: &[u8]) -> Result<MessageSignature, MessageSignatureError> {
if bytes.len() != 65 {
return Err(MessageSignatureError::InvalidLength);
}
// We just check this here so we can safely subtract further.
if bytes[0] < 27 {
return Err(MessageSignatureError::InvalidEncoding(secp256k1::Error::InvalidRecoveryId));
};
let recid = RecoveryId::from_i32(((bytes[0] - 27) & 0x03) as i32)?;
Ok(MessageSignature {
signature: RecoverableSignature::from_compact(&bytes[1..], recid)?,
compressed: ((bytes[0] - 27) & 0x04) != 0,
})
}
/// Attempt to recover a public key from the signature and the signed message.
///
/// To get the message hash from a message, use [signed_msg_hash].
pub fn recover_pubkey<C: secp256k1::Verification>(
&self,
secp_ctx: &secp256k1::Secp256k1<C>,
msg_hash: sha256d::Hash
) -> Result<PublicKey, secp256k1::Error> {
let msg = secp256k1::Message::from_slice(&msg_hash[..])?;
let pubkey = secp_ctx.recover(&msg, &self.signature)?;
Ok(PublicKey {
key: pubkey,
compressed: self.compressed,
})
}
/// Verify that the signature signs the message and was signed by the given address.
///
/// To get the message hash from a message, use [signed_msg_hash].
pub fn is_signed_by_address<C: secp256k1::Verification>(
&self,
secp_ctx: &secp256k1::Secp256k1<C>,
address: &Address,
msg_hash: sha256d::Hash
) -> Result<bool, secp256k1::Error> {
let pubkey = self.recover_pubkey(&secp_ctx, msg_hash)?;
Ok(match address.address_type() {
Some(AddressType::P2pkh) => {
*address == Address::p2pkh(&pubkey, address.network)
}
Some(AddressType::P2sh) => false,
Some(AddressType::P2wpkh) => {
// Only compressed pubkeys are allowed in p2wpkh.
pubkey.compressed &&
*address == Address::p2wpkh(&pubkey, address.network).expect("compressed pk")
}
Some(AddressType::P2wsh) => false,
None => false,
})
}
#[cfg(feature = "base64")]
/// Convert a signature from base64 encoding.
pub fn from_base64(s: &str) -> Result<MessageSignature, MessageSignatureError> {
let bytes = ::base64::decode(s).map_err(|_| MessageSignatureError::InvalidBase64)?;
MessageSignature::from_slice(&bytes)
}
#[cfg(feature = "base64")]
/// Convert to base64 encoding.
pub fn to_base64(&self) -> String {
::base64::encode(&self.serialize()[..])
}
}
#[cfg(feature = "base64")]
impl fmt::Display for MessageSignature {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let bytes = self.serialize();
// This avoids the allocation of a String.
write!(f, "{}", ::base64::display::Base64Display::with_config(
&bytes[..], ::base64::STANDARD))
}
}
#[cfg(feature = "base64")]
impl ::std::str::FromStr for MessageSignature {
type Err = MessageSignatureError;
fn from_str(s: &str) -> Result<MessageSignature, MessageSignatureError> {
MessageSignature::from_base64(s)
}
}
}
/// Search for `needle` in the vector `haystack` and remove every
/// instance of it, returning the number of instances removed.
/// Loops through the vector opcode by opcode, skipping pushed data.
@ -59,7 +236,6 @@ pub fn script_find_and_remove(haystack: &mut Vec<u8>, needle: &[u8]) -> usize {
/// Hash message for signature using Bitcoin's message signing format
pub fn signed_msg_hash(msg: &str) -> sha256d::Hash {
let mut engine = sha256d::Hash::engine();
engine.input(MSG_SIGN_PREFIX);
let msg_len = encode::VarInt(msg.len() as u64);
@ -119,5 +295,37 @@ mod tests {
let hash = signed_msg_hash("test");
assert_eq!(hash.to_hex(), "a6f87fe6d58a032c320ff8d1541656f0282c2c7bfcc69d61af4c8e8ed528e49c");
}
#[test]
#[cfg(all(feature = "secp-recovery", feature = "base64"))]
fn test_message_signature() {
use std::str::FromStr;
use secp256k1;
let secp = secp256k1::Secp256k1::new();
let message = "rust-bitcoin MessageSignature test";
let msg_hash = super::signed_msg_hash(&message);
let msg = secp256k1::Message::from_slice(&msg_hash).unwrap();
let privkey = secp256k1::SecretKey::new(&mut secp256k1::rand::thread_rng());
let secp_sig = secp.sign_recoverable(&msg, &privkey);
let signature = super::MessageSignature {
signature: secp_sig,
compressed: true,
};
assert_eq!(signature.to_base64(), signature.to_string());
let signature2 = super::MessageSignature::from_str(&signature.to_string()).unwrap();
let pubkey = signature2.recover_pubkey(&secp, msg_hash).unwrap();
assert_eq!(pubkey.compressed, true);
assert_eq!(pubkey.key, secp256k1::PublicKey::from_secret_key(&secp, &privkey));
let p2pkh = ::Address::p2pkh(&pubkey, ::Network::Bitcoin);
assert_eq!(signature2.is_signed_by_address(&secp, &p2pkh, msg_hash), Ok(true));
let p2wpkh = ::Address::p2wpkh(&pubkey, ::Network::Bitcoin).unwrap();
assert_eq!(signature2.is_signed_by_address(&secp, &p2wpkh, msg_hash), Ok(true));
let p2shwpkh = ::Address::p2shwpkh(&pubkey, ::Network::Bitcoin).unwrap();
assert_eq!(signature2.is_signed_by_address(&secp, &p2shwpkh, msg_hash), Ok(false));
}
}