add signing support

Cargo.lock

@@ -145,6 +145,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bumpalo"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e8c087f005730276d1096a652e92a8bacee2e2472bcc9715a74d2bec38b5820"
+
 [[package]]
 name = "byteorder"
 version = "1.3.4"
@@ -350,6 +356,15 @@ version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
+[[package]]
+name = "js-sys"
+version = "0.3.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca059e81d9486668f12d455a4ea6daa600bd408134cd17e3d3fb5a32d1f016f8"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "kv"
 version = "0.10.0"
@@ -398,6 +413,15 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "log"
+version = "0.4.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fabed175da42fed1fa0746b0ea71f412aa9d35e76e95e59b192c64b9dc2bf8b"
+dependencies = [
+ "cfg-if 0.1.10",
+]
+
 [[package]]
 name = "memchr"
 version = "2.3.4"
@@ -445,6 +469,12 @@ version = "0.22.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d3b63360ec3cb337817c2dbd47ab4a0f170d285d8e5a2064600f3def1402397"
 
+[[package]]
+name = "once_cell"
+version = "1.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13bd41f508810a131401606d54ac32a467c97172d74ba7662562ebba5ad07fa0"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.19"
@@ -766,6 +796,21 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "ring"
+version = "0.16.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c5911690c9b773bab7e657471afc207f3827b249a657241327e3544d79bcabdd"
+dependencies = [
+ "cc",
+ "libc",
+ "once_cell",
+ "spin",
+ "untrusted",
+ "web-sys",
+ "winapi",
+]
+
 [[package]]
 name = "rmp"
 version = "0.8.9"
@@ -854,6 +899,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "spin"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
+
 [[package]]
 name = "strsim"
 version = "0.8.0"
@@ -896,6 +947,7 @@ dependencies = [
  "kv",
  "lmdb-rkv",
  "proptest",
+ "ring",
  "serde",
  "serde_json",
  "tempdir",
@@ -1025,6 +1077,12 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
 
+[[package]]
+name = "untrusted"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
+
 [[package]]
 name = "uuid"
 version = "0.8.1"
@@ -1062,6 +1120,70 @@ version = "0.10.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ac64ead5ea5f05873d7c12b545865ca2b8d28adfc50a49b84770a3a97265d42"
+dependencies = [
+ "cfg-if 0.1.10",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f22b422e2a757c35a73774860af8e112bff612ce6cb604224e8e47641a9e4f68"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b13312a745c08c469f0b292dd2fcd6411dba5f7160f593da6ef69b64e407038"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f249f06ef7ee334cc3b8ff031bfc11ec99d00f34d86da7498396dc1e3b1498fe"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d649a3145108d7d3fbcde896a468d1bd636791823c9921135218ad89be08307"
+
+[[package]]
+name = "web-sys"
+version = "0.3.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bf6ef87ad7ae8008e15a355ce696bed26012b7caa21605188cfd8214ab51e2d"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"

taskchampion/Cargo.toml

@@ -12,6 +12,7 @@ chrono = { version = "0.4.10", features = ["serde"] }
 failure = {version = "0.1.5", features = ["derive"] }
 kv = {version = "0.10.0", features = ["msgpack-value"]}
 lmdb-rkv = {version = "0.12.3"}
+ring = { version = "0.16.17", features = ["std"] }
 
 [dev-dependencies]
 proptest = "0.9.4"

taskchampion/src/server/mod.rs

@@ -1,6 +1,7 @@
 #[cfg(test)]
 pub(crate) mod test;
 
+mod signing;
 mod types;
 
 pub use types::{Blob, Server, VersionAdd};

taskchampion/src/server/signing.rs

@@ -0,0 +1,87 @@
+#![allow(dead_code)] // TODO: temporary until this module is used
+//! This is a general wrapper around an asymmetric-key signature system.
+
+use failure::Fallible;
+use ring::{
+    rand,
+    signature::{Ed25519KeyPair, KeyPair, Signature, UnparsedPublicKey, ED25519},
+};
+
+type PublicKey = Vec<u8>;
+type PrivateKey = Vec<u8>;
+
+/// Generate a pair of (public, private) key material (in fact the private key is a keypair)
+pub fn new_keypair() -> Fallible<(PublicKey, PrivateKey)> {
+    let rng = rand::SystemRandom::new();
+    let key_pkcs8 = Ed25519KeyPair::generate_pkcs8(&rng)?;
+    let key_pair = Ed25519KeyPair::from_pkcs8(key_pkcs8.as_ref())?;
+    let pub_key = key_pair.public_key();
+    Ok((
+        pub_key.as_ref().to_vec() as PublicKey,
+        key_pkcs8.as_ref().to_vec() as PrivateKey,
+    ))
+}
+
+pub struct Signer {
+    key_pair: Ed25519KeyPair,
+}
+
+impl Signer {
+    /// Create a new signer, given a pkcs#8 v2 document containing the keypair.
+    fn new(priv_key: PrivateKey) -> Fallible<Self> {
+        Ok(Self {
+            key_pair: Ed25519KeyPair::from_pkcs8(&priv_key)?,
+        })
+    }
+
+    pub fn sign<B: AsRef<[u8]>>(&self, message: B) -> Fallible<Signature> {
+        Ok(self.key_pair.sign(message.as_ref()))
+    }
+}
+
+pub struct Verifier {
+    pub_key: PublicKey,
+}
+
+impl Verifier {
+    fn new(pub_key: PublicKey) -> Fallible<Self> {
+        Ok(Self { pub_key })
+    }
+
+    pub fn verify<B1: AsRef<[u8]>, B2: AsRef<[u8]>>(
+        &self,
+        message: B1,
+        signature: B2,
+    ) -> Fallible<()> {
+        let pub_key = UnparsedPublicKey::new(&ED25519, &self.pub_key);
+        Ok(pub_key.verify(message.as_ref(), signature.as_ref())?)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_verify_ok() -> Fallible<()> {
+        let (public, private) = new_keypair()?;
+        let signer = Signer::new(private)?;
+        let verifier = Verifier::new(public)?;
+
+        let message = b"Hello, world";
+        let signature = signer.sign(message)?;
+        verifier.verify(message, signature)
+    }
+
+    #[test]
+    fn test_verify_bad_message() -> Fallible<()> {
+        let (public, private) = new_keypair()?;
+        let signer = Signer::new(private)?;
+        let verifier = Verifier::new(public)?;
+
+        let message = b"Hello, world";
+        let signature = signer.sign(message)?;
+        assert!(verifier.verify(b"Hello, cruel world", signature).is_err());
+        Ok(())
+    }
+}