chore(kms): prefer new aliasArn to keyArn for getting arn of an alias

packages/aws-cdk-lib/aws-kms/lib/alias.ts

@@ -59,6 +59,12 @@ abstract class AliasBase extends Resource implements IAlias {
 
   public abstract readonly aliasTargetKey: IKey;
 
+  /**
+   * The ARN of the alias.
+   *
+   * @attribute
+   * @deprecated use `aliasArn` instead
+   */
   public get keyArn(): string {
     return Stack.of(this).formatArn({
       service: 'kms',
@@ -67,6 +73,15 @@ abstract class AliasBase extends Resource implements IAlias {
     });
   }
 
+  /**
+   * The ARN of the alias.
+   *
+   * @attribute
+   */
+  public get aliasArn(): string {
+    return this.keyArn;
+  }
+
   public get keyId(): string {
     return this.aliasName;
   }

packages/aws-cdk-lib/aws-kms/test/alias.test.ts

@@ -357,6 +357,16 @@ test('does not add alias if starts with token', () => {
   });
 });
 
+test('aliasArn and keyArn from alias should match', () => {
+  const app = new App();
+  const stack = new Stack(app, 'Test');
+  const key = new Key(stack, 'Key');
+
+  const alias = new Alias(stack, 'Alias', { targetKey: key, aliasName: 'alias/foo' });
+
+  expect(alias.aliasArn).toEqual(alias.keyArn);
+});
+
 class AliasOutputsConstruct extends Construct {
   constructor(scope: Construct, id: string, key: IKey) {
     super(scope, id);