Added Nonce Enforcer as Caveat in Delegation Core

packages/delegation-core/src/caveats/index.ts

@@ -5,3 +5,4 @@ export { createExactCalldataTerms } from './exactCalldata';
 export { createNativeTokenStreamingTerms } from './nativeTokenStreaming';
 export { createERC20StreamingTerms } from './erc20Streaming';
 export { createERC20TokenPeriodTransferTerms } from './erc20TokenPeriodTransfer';
+export { createNonceTerms } from './nonce';

packages/delegation-core/src/caveats/nonce.ts

@@ -0,0 +1,75 @@
+import { isHexString } from '@metamask/utils';
+import type { BytesLike } from '@metamask/utils';
+
+import {
+  defaultOptions,
+  prepareResult,
+  type EncodingOptions,
+  type ResultValue,
+} from '../returns';
+import type { Hex } from '../types';
+
+// char length of 32 byte hex string (including 0x prefix)
+const MAX_NONCE_STRING_LENGTH = 66;
+
+/**
+ * Terms for configuring a Nonce caveat.
+ */
+export type NonceTerms = {
+  /** The nonce as a hex string to allow bulk revocation of delegations. */
+  nonce: BytesLike;
+};
+
+/**
+ * Creates terms for a Nonce caveat that uses a nonce value for bulk revocation of delegations.
+ *
+ * @param terms - The terms for the Nonce caveat.
+ * @param encodingOptions - The encoding options for the result.
+ * @returns The terms as a 32-byte hex string.
+ * @throws Error if the nonce is invalid.
+ */
+export function createNonceTerms(
+  terms: NonceTerms,
+  encodingOptions?: EncodingOptions<'hex'>,
+): Hex;
+export function createNonceTerms(
+  terms: NonceTerms,
+  encodingOptions: EncodingOptions<'bytes'>,
+): Uint8Array;
+/**
+ * Creates terms for a Nonce caveat that uses a nonce value for bulk revocation of delegations.
+ *
+ * @param terms - The terms for the Nonce caveat.
+ * @param encodingOptions - The encoding options for the result.
+ * @returns The terms as a 32-byte hex string.
+ * @throws Error if the nonce is invalid.
+ */
+export function createNonceTerms(
+  terms: NonceTerms,
+  encodingOptions: EncodingOptions<ResultValue> = defaultOptions,
+): Hex | Uint8Array {
+  const { nonce } = terms;
+
+  if (!nonce || nonce === '0x') {
+    throw new Error('Invalid nonce: must be a non-empty hex string');
+  }
+
+  if (typeof nonce !== 'string' || !nonce.startsWith('0x')) {
+    throw new Error('Invalid nonce: must be a valid hex string');
+  }
+
+  if (!isHexString(nonce)) {
+    throw new Error('Invalid nonce: must be a valid hex string');
+  }
+
+  if (nonce.length > MAX_NONCE_STRING_LENGTH) {
+    throw new Error('Invalid nonce: must be 32 bytes or less in length');
+  }
+
+  // Remove '0x' prefix for padding, then add it back
+  const nonceWithoutPrefix = nonce.slice(2);
+  const paddedNonce = nonceWithoutPrefix.padStart(64, '0'); // 64 hex chars = 32 bytes
+  const hexValue = `0x${paddedNonce}`;
+
+  return prepareResult(hexValue, encodingOptions);
+}

packages/delegation-core/src/index.ts

@@ -12,6 +12,7 @@ export {
   createNativeTokenStreamingTerms,
   createERC20StreamingTerms,
   createERC20TokenPeriodTransferTerms,
+  createNonceTerms,
 } from './caveats';
 
 export {

packages/delegation-core/test/caveats/nonce.test.ts

@@ -0,0 +1,204 @@
+import { describe, it, expect } from 'vitest';
+
+import { createNonceTerms } from '../../src/caveats/nonce';
+
+describe('createNonceTerms', () => {
+  const EXPECTED_BYTE_LENGTH = 32; // 32 bytes for nonce
+
+  it('creates valid terms for simple nonce', () => {
+    const nonce = '0x1234567890abcdef';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x0000000000000000000000000000000000000000000000001234567890abcdef',
+    );
+  });
+
+  it('creates valid terms for zero nonce', () => {
+    const nonce = '0x0';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x0000000000000000000000000000000000000000000000000000000000000000',
+    );
+  });
+
+  it('creates valid terms for minimal nonce', () => {
+    const nonce = '0x1';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x0000000000000000000000000000000000000000000000000000000000000001',
+    );
+  });
+
+  it('creates valid terms for full 32-byte nonce', () => {
+    const nonce =
+      '0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(nonce);
+  });
+
+  it('creates valid terms for uppercase hex nonce', () => {
+    const nonce = '0x1234567890ABCDEF';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x0000000000000000000000000000000000000000000000001234567890ABCDEF',
+    );
+  });
+
+  it('creates valid terms for mixed case hex nonce', () => {
+    const nonce = '0x1234567890AbCdEf';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x0000000000000000000000000000000000000000000000001234567890AbCdEf',
+    );
+  });
+
+  it('pads shorter hex values with leading zeros', () => {
+    const nonce = '0xff';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x00000000000000000000000000000000000000000000000000000000000000ff',
+    );
+  });
+
+  it('throws an error for empty nonce', () => {
+    const nonce = '0x';
+
+    expect(() => createNonceTerms({ nonce })).toThrow(
+      'Invalid nonce: must be a non-empty hex string',
+    );
+  });
+
+  it('throws an error for undefined nonce', () => {
+    expect(() => createNonceTerms({ nonce: undefined as any })).toThrow(
+      'Invalid nonce: must be a non-empty hex string',
+    );
+  });
+
+  it('throws an error for null nonce', () => {
+    expect(() => createNonceTerms({ nonce: null as any })).toThrow(
+      'Invalid nonce: must be a non-empty hex string',
+    );
+  });
+
+  it('throws an error for nonce without 0x prefix', () => {
+    const nonce = '1234567890abcdef' as any;
+
+    expect(() => createNonceTerms({ nonce })).toThrow(
+      'Invalid nonce: must be a valid hex string',
+    );
+  });
+
+  it('throws an error for invalid hex characters', () => {
+    const nonce = '0x1234567890abcdefg' as any;
+
+    expect(() => createNonceTerms({ nonce })).toThrow(
+      'Invalid nonce: must be a valid hex string',
+    );
+  });
+
+  it('throws an error for non-string nonce', () => {
+    const nonce = 123456 as any;
+
+    expect(() => createNonceTerms({ nonce })).toThrow(
+      'Invalid nonce: must be a valid hex string',
+    );
+  });
+
+  it('throws an error for nonce longer than 32 bytes', () => {
+    // 33 bytes (66 hex chars + 0x prefix = 68 chars total, which exceeds 66)
+    const nonce =
+      '0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12' as any;
+
+    expect(() => createNonceTerms({ nonce })).toThrow(
+      'Invalid nonce: must be 32 bytes or less in length',
+    );
+  });
+
+  it('accepts nonce with exactly 32 bytes', () => {
+    // 32 bytes (64 hex chars + 0x prefix = 66 chars total)
+    const nonce =
+      '0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef';
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(nonce);
+  });
+
+  it('throws an error for string that looks like hex but has odd length', () => {
+    const nonce = '0x123' as any;
+    // This should still work as we pad it
+    const result = createNonceTerms({ nonce });
+
+    expect(result).toStrictEqual(
+      '0x0000000000000000000000000000000000000000000000000000000000000123',
+    );
+  });
+
+  // Tests for bytes return type
+  describe('bytes return type', () => {
+    it('returns Uint8Array when bytes encoding is specified', () => {
+      const nonce = '0x1234567890abcdef';
+      const result = createNonceTerms({ nonce }, { out: 'bytes' });
+
+      expect(result).toBeInstanceOf(Uint8Array);
+      expect(result).toHaveLength(EXPECTED_BYTE_LENGTH);
+    });
+
+    it('returns Uint8Array for minimal nonce with bytes encoding', () => {
+      const nonce = '0x1';
+      const result = createNonceTerms({ nonce }, { out: 'bytes' });
+
+      expect(result).toBeInstanceOf(Uint8Array);
+      expect(result).toHaveLength(EXPECTED_BYTE_LENGTH);
+      // Should be 31 zeros followed by 1
+      const expectedBytes = new Array(EXPECTED_BYTE_LENGTH).fill(0);
+      expectedBytes[EXPECTED_BYTE_LENGTH - 1] = 1;
+      expect(Array.from(result)).toEqual(expectedBytes);
+    });
+
+    it('returns Uint8Array for zero nonce with bytes encoding', () => {
+      const nonce = '0x0';
+      const result = createNonceTerms({ nonce }, { out: 'bytes' });
+
+      expect(result).toBeInstanceOf(Uint8Array);
+      expect(result).toHaveLength(EXPECTED_BYTE_LENGTH);
+      // Should be all zeros
+      const expectedBytes = new Array(EXPECTED_BYTE_LENGTH).fill(0);
+      expect(Array.from(result)).toEqual(expectedBytes);
+    });
+
+    it('returns Uint8Array for full nonce with bytes encoding', () => {
+      const nonce =
+        '0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef';
+      const result = createNonceTerms({ nonce }, { out: 'bytes' });
+
+      expect(result).toBeInstanceOf(Uint8Array);
+      expect(result).toHaveLength(EXPECTED_BYTE_LENGTH);
+      // Convert expected hex to bytes for comparison
+      const expectedBytes = [
+        0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef, 0x12, 0x34, 0x56, 0x78,
+        0x90, 0xab, 0xcd, 0xef, 0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef,
+        0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef,
+      ];
+      expect(Array.from(result)).toEqual(expectedBytes);
+    });
+
+    it('returns Uint8Array for padded hex values with bytes encoding', () => {
+      const nonce = '0xff';
+      const result = createNonceTerms({ nonce }, { out: 'bytes' });
+
+      expect(result).toBeInstanceOf(Uint8Array);
+      expect(result).toHaveLength(EXPECTED_BYTE_LENGTH);
+      // Should be 31 zeros followed by 0xff
+      const expectedBytes = new Array(EXPECTED_BYTE_LENGTH).fill(0);
+      expectedBytes[EXPECTED_BYTE_LENGTH - 1] = 0xff;
+      expect(Array.from(result)).toEqual(expectedBytes);
+    });
+  });
+});

packages/delegation-toolkit/src/caveatBuilder/nonceBuilder.ts

@@ -1,12 +1,10 @@
-import { type Hex, isHex, pad } from 'viem';
+import { createNonceTerms } from '@metamask/delegation-core';
+import { type Hex } from 'viem';
 
 import type { DeleGatorEnvironment, Caveat } from '../types';
 
 export const nonce = 'nonce';
 
-// char length of 32 byte hex string
-const MAX_NONCE_STRING_LENGTH = 66;
-
 export type NonceBuilderConfig = {
   /**
    * A nonce as a hex string to allow bulk revocation of delegations.
@@ -28,19 +26,7 @@ export const nonceBuilder = (
 ): Caveat => {
   const { nonce: nonceValue } = config;
 
-  if (!nonceValue || nonceValue === '0x') {
-    throw new Error('Invalid nonce: must be a non-empty hex string');
-  }
-
-  if (!isHex(nonceValue)) {
-    throw new Error('Invalid nonce: must be a valid hex string');
-  }
-
-  if (nonceValue.length > MAX_NONCE_STRING_LENGTH) {
-    throw new Error('Invalid nonce: must be 32 bytes or less in length');
-  }
-
-  const terms = pad(nonceValue, { size: 32 });
+  const terms = createNonceTerms({ nonce: nonceValue });
 
   const {
     caveatEnforcers: { NonceEnforcer },