Add signmessage example with EIP-191 message signing and verification

ci-test.sh

@@ -28,3 +28,4 @@ dub test -q --d-version=IntegrationTest -- --threads=1
 dub run deth:devtest -q
 dub run deth:transfer -q
 dub run deth:deploybytecode -q
+dub run deth:signmessage -q

dub.sdl

@@ -13,3 +13,4 @@ targetType "library"
 subPackage "examples/devtest"
 subPackage "examples/transfer"
 subPackage "examples/deploybytecode"
+subPackage "examples/signmessage"

examples/signmessage/.gitignore

@@ -0,0 +1,2 @@
+signmessage
+deth_signmessage

examples/signmessage/dub.sdl

@@ -0,0 +1,6 @@
+name "signmessage"
+description "An example for EIP-191 message signing and verification"
+authors "Hiroki Noda"
+copyright "Copyright © 2026, Hiroki Noda"
+dependency "deth" version="*" path="../../"
+license "MIT"

examples/signmessage/dub.selections.json

@@ -0,0 +1,28 @@
+{
+	"fileVersion": 1,
+	"versions": {
+		"autointf": {"version":"1a3086131aee6061dab455e9d1abab683d9d7109","repository":"git+https://github.com/kubo39/d-autointf"},
+		"diet-ng": "1.8.4",
+		"during": "0.3.0",
+		"eventcore": "0.9.39",
+		"keccak-tiny": "1.2.1",
+		"mir-linux-kernel": "1.2.1",
+		"openssl": "3.4.0",
+		"openssl-static": "1.0.5+3.0.8",
+		"rlp": "0.4.0",
+		"secp256k1": "2.5.1",
+		"silly": "1.1.1",
+		"stdx-allocator": "2.77.5",
+		"structjson": "2.100.1",
+		"taggedalgebraic": "1.0.1",
+		"tynukrpc": {"version":"204c5c8c4c37ae4411ae9e4346632977599df0df","repository":"git+https://github.com/kubo39/d-rpc-forked"},
+		"unit-threaded": "2.2.3",
+		"vibe-container": "1.7.1",
+		"vibe-core": "2.13.5",
+		"vibe-d": "0.10.3",
+		"vibe-http": "1.3.3",
+		"vibe-inet": "1.2.0",
+		"vibe-serialization": "1.1.3",
+		"vibe-stream": "1.4.0"
+	}
+}

examples/signmessage/source/app.d

@@ -0,0 +1,34 @@
+// EIP-191 message signing and verification example.
+// https://eips.ethereum.org/EIPS/eip-191
+//
+// No network connection required - signing and verification are purely local.
+
+import std.stdio;
+
+import deth;
+
+void main()
+{
+    // Anvil's first default account private key
+    auto signer = new Signer(
+        "ac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80"
+    );
+    const signerAddress = signer.address;
+    writeln("Signer:    ", signerAddress.convTo!string.ox);
+
+    // Sign a message using EIP-191 (personal_sign format)
+    auto message = "Hello, Ethereum!";
+    auto sig = signer.signMessage(message);
+
+    // Ethereum encodes the recovery ID as v = recid + 27
+    ubyte v = cast(ubyte)(sig.recid + 27);
+    writefln("Signature: r=%s s=%s v=%d",
+        sig.r.convTo!string.ox, sig.s.convTo!string.ox, v);
+
+    // Recover signer address from message + signature
+    const recovered = recoverMessageSigner(message, sig);
+    writeln("Recovered: ", recovered.convTo!string.ox);
+
+    assert(recovered == signerAddress);
+    writeln("Verification: OK");
+}

source/deth/signer.d

@@ -66,6 +66,16 @@ private:
     secp256k1 keypair;
 }
 
+/// Recover the signer address from a message and its EIP-191 signature.
+/// This can be used to verify that a signature was produced by the holder of the
+/// private key corresponding to an Ethereum address.
+Address recoverMessageSigner(string message, Signature sig) @trusted
+{
+    import secp256k1 : ecRecover;
+
+    return ecRecover(sig, eip191PrefixedMessage(cast(bytes) message));
+}
+
 /// Hash a message according to EIP-191.
 Hash eip191HashMessage(const bytes message) @safe
 {