feat: add ERC-55 support to ExecutionAddress

packages/types/package.json

@@ -74,7 +74,8 @@
   "types": "lib/index.d.ts",
   "dependencies": {
     "@chainsafe/ssz": "^0.14.0",
-    "@lodestar/params": "^1.15.0"
+    "@lodestar/params": "^1.15.0",
+    "ethereum-cryptography": "^2.0.0"
   },
   "keywords": [
     "ethereum",

packages/types/src/bellatrix/sszTypes.ts

@@ -9,7 +9,7 @@ import {
 import {ssz as primitiveSsz} from "../primitive/index.js";
 import {ssz as phase0Ssz} from "../phase0/index.js";
 import {ssz as altairSsz} from "../altair/index.js";
-import {stringType} from "../utils/StringType.js";
+import {stringType} from "../utils/stringType.js";
 
 const {
   Bytes32,

packages/types/src/index.ts

@@ -3,6 +3,6 @@ export * as ssz from "./sszTypes.js";
 // Typeguards
 export * from "./utils/typeguards.js";
 // String type
-export {StringType, stringType} from "./utils/StringType.js";
+export {StringType, stringType} from "./utils/stringType.js";
 // Container utils
 export * from "./utils/container.js";

packages/types/src/primitive/sszTypes.ts

@@ -1,4 +1,5 @@
 import {ByteVectorType, UintNumberType, UintBigintType, BooleanType} from "@chainsafe/ssz";
+import {ExecutionAddressType} from "../utils/executionAddress.js";
 
 export const Boolean = new BooleanType();
 export const Byte = new UintNumberType(1);
@@ -61,4 +62,4 @@ export const BLSPubkey = Bytes48;
 export const BLSSignature = Bytes96;
 export const Domain = Bytes32;
 export const ParticipationFlags = new UintNumberType(1, {setBitwiseOR: true});
-export const ExecutionAddress = Bytes20;
+export const ExecutionAddress = new ExecutionAddressType();

packages/types/src/utils/executionAddress.ts

@@ -0,0 +1,48 @@
+import {keccak256} from "ethereum-cryptography/keccak.js";
+import {ByteVectorType} from "@chainsafe/ssz";
+
+export type ByteVector = Uint8Array;
+
+export class ExecutionAddressType extends ByteVectorType {
+  constructor() {
+    super(20, {typeName: "ExecutionAddress"});
+  }
+  toJson(value: ByteVector): unknown {
+    const str = super.toJson(value) as string;
+    return toChecksumAddress(str);
+  }
+}
+
+function isAddressValid(address: string): boolean {
+  return /^(0x)?[0-9a-f]{40}$/i.test(address);
+}
+
+/**
+ * Formats an address according to [ERC55](https://eips.ethereum.org/EIPS/eip-55)
+ */
+export function toChecksumAddress(address: string): string {
+  if (!isAddressValid(address)) {
+    throw Error(`Invalid address: ${address}`);
+  }
+
+  const rawAddress = (address.startsWith("0x") ? address.slice(2) : address).toLowerCase();
+  const chars = rawAddress.split("");
+
+  // Inspired by https://github.com/ethers-io/ethers.js/blob/cac1da1f912c2ae9ba20f25aa51a91766673cd76/src.ts/address/address.ts#L8
+  const expanded = new Uint8Array(chars.length);
+  for (let i = 0; i < expanded.length; i++) {
+    expanded[i] = rawAddress[i].charCodeAt(0);
+  }
+
+  const hashed = keccak256(expanded);
+  for (let i = 0; i < chars.length; i += 2) {
+    if (hashed[i >> 1] >> 4 >= 8) {
+      chars[i] = chars[i].toUpperCase();
+    }
+    if ((hashed[i >> 1] & 0x0f) >= 8) {
+      chars[i + 1] = chars[i + 1].toUpperCase();
+    }
+  }
+
+  return "0x" + chars.join("");
+}

packages/types/test/unit/executionAddress.test.ts

@@ -0,0 +1,72 @@
+import {describe, it, expect} from "vitest";
+import {toChecksumAddress} from "../../src/utils/executionAddress.js";
+
+describe("toChecksumAddress", () => {
+  it("should fail with invalid addresses", () => {
+    expect(() => toChecksumAddress("1234")).toThrowError("Invalid address: 1234");
+    expect(() => toChecksumAddress("0x1234")).toThrowError("Invalid address: 0x1234");
+  });
+
+  it("should format addresses as ERC55", () => {
+    type TestCase = {
+      address: string;
+      checksumAddress: string;
+    };
+
+    const testCases: TestCase[] = [
+      // Input all caps
+      {
+        address: "0x52908400098527886E0F7030069857D2E4169EE7",
+        checksumAddress: "0x52908400098527886E0F7030069857D2E4169EE7",
+      },
+      {
+        address: "0xDE709F2102306220921060314715629080E2FB77",
+        checksumAddress: "0xde709f2102306220921060314715629080e2fb77",
+      },
+      // Without 0x prefix
+      {
+        address: "52908400098527886e0f7030069857d2e4169ee7",
+        checksumAddress: "0x52908400098527886E0F7030069857D2E4169EE7",
+      },
+      // All caps
+      {
+        address: "0x52908400098527886e0f7030069857d2e4169ee7",
+        checksumAddress: "0x52908400098527886E0F7030069857D2E4169EE7",
+      },
+      {
+        address: "0x8617e340b3d01fa5f11f306f4090fd50e238070d",
+        checksumAddress: "0x8617E340B3D01FA5F11F306F4090FD50E238070D",
+      },
+      // All lower
+      {
+        address: "0xde709f2102306220921060314715629080e2fb77",
+        checksumAddress: "0xde709f2102306220921060314715629080e2fb77",
+      },
+      {
+        address: "0x27b1fdb04752bbc536007a920d24acb045561c26",
+        checksumAddress: "0x27b1fdb04752bbc536007a920d24acb045561c26",
+      },
+      // Normal
+      {
+        address: "0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed",
+        checksumAddress: "0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed",
+      },
+      {
+        address: "0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359",
+        checksumAddress: "0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359",
+      },
+      {
+        address: "0xdbf03b407c01e7cd3cbea99509d93f8dddc8c6fb",
+        checksumAddress: "0xdbF03B407c01E7cD3CBea99509d93f8DDDC8C6FB",
+      },
+      {
+        address: "0xd1220a0cf47c7b9be7a2e6ba89f429762e7b9adb",
+        checksumAddress: "0xD1220A0cf47c7B9Be7A2E6BA89F429762e7b9aDb",
+      },
+    ];
+
+    for (const {address, checksumAddress} of testCases) {
+      expect(toChecksumAddress(address)).toBe(checksumAddress);
+    }
+  });
+});