crypto: runtime-deprecate calling Hmac.digest() more than once

Emit a DEP0206 deprecation warning when Hmac.digest() is called on an
already-finalized instance. This behavior is inconsistent with
Hash.digest() which throws ERR_CRYPTO_HASH_FINALIZED.

Fixes: #62838
Co-authored-by: Filip Skokan <panva.ip@gmail.com>
Signed-off-by: developers-universe-1 <madelynreyes2026@gmail.com>
Signed-off-by: Filip Skokan <panva.ip@gmail.com>

Author: developers-universe-1

doc/api/deprecations.md

@@ -4562,12 +4562,15 @@ removed in a future version of Node.js.
 
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/63624
+    description: Runtime deprecation.
   - version: v26.2.0
     pr-url: https://github.com/nodejs/node/pull/63121
     description: Documentation-only deprecation.
 -->
 
-Type: Documentation-only
+Type: Runtime
 
 Calling `hmac.digest()` more than once returns an empty buffer instead of
 throwing an error. This behavior is inconsistent with `hash.digest()` and

lib/internal/crypto/hash.js

@@ -87,6 +87,11 @@ const maybeEmitDeprecationWarning = getDeprecationWarningEmitter(
   },
 );
 
+const emitHmacDigestDeprecation = getDeprecationWarningEmitter(
+  'DEP0206',
+  'Calling Hmac.digest() more than once is deprecated.',
+);
+
 function Hash(algorithm, options) {
   if (!new.target)
     return new Hash(algorithm, options);
@@ -183,6 +188,7 @@ Hmac.prototype.digest = function digest(outputEncoding) {
   const state = this[kState];
 
   if (state[kFinalized]) {
+    emitHmacDigestDeprecation();
     const buf = Buffer.from('');
     if (outputEncoding && outputEncoding !== 'buffer')
       return buf.toString(outputEncoding);

test/parallel/test-crypto-dep0181.js

@@ -0,0 +1,19 @@
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+
+const assert = require('assert');
+const crypto = require('crypto');
+
+common.expectWarning({
+  DeprecationWarning: {
+    DEP0181: 'crypto.Hmac constructor is deprecated.',
+  },
+});
+
+const Hmac = crypto.Hmac;
+const instance = crypto.Hmac('sha256', 'Node');
+assert(instance instanceof Hmac, 'Hmac is expected to return a new instance' +
+                                 ' when called without `new`');

test/parallel/test-crypto-dep0206.js

@@ -0,0 +1,56 @@
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+
+const assert = require('assert');
+const crypto = require('crypto');
+
+common.expectWarning({
+  DeprecationWarning: {
+    DEP0206: 'Calling Hmac.digest() more than once is deprecated.',
+  },
+});
+
+// Verify runtime deprecation warning for calling digest() more than once.
+{
+  const h = crypto.createHmac('sha1', 'key').update('data');
+  h.digest('hex');
+  h.digest('hex');
+}
+
+// Check initialized -> uninitialized state transition after calling digest().
+{
+  const expected =
+      '\u0010\u0041\u0052\u00c5\u00bf\u00dc\u00a0\u007b\u00c6\u0033' +
+      '\u00ee\u00bd\u0046\u0019\u009f\u0002\u0055\u00c9\u00f4\u009d';
+  {
+    const h = crypto.createHmac('sha1', 'key').update('data');
+    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(expected, 'latin1'));
+    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(''));
+  }
+  {
+    const h = crypto.createHmac('sha1', 'key').update('data');
+    assert.strictEqual(h.digest('latin1'), expected);
+    assert.strictEqual(h.digest('latin1'), '');
+  }
+}
+
+// Check initialized -> uninitialized state transition after calling digest().
+// Calls to update() omitted intentionally.
+{
+  const expected =
+      '\u00f4\u002b\u00b0\u00ee\u00b0\u0018\u00eb\u00bd\u0045\u0097' +
+      '\u00ae\u0072\u0013\u0071\u001e\u00c6\u0007\u0060\u0084\u003f';
+  {
+    const h = crypto.createHmac('sha1', 'key');
+    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(expected, 'latin1'));
+    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(''));
+  }
+  {
+    const h = crypto.createHmac('sha1', 'key');
+    assert.strictEqual(h.digest('latin1'), expected);
+    assert.strictEqual(h.digest('latin1'), '');
+  }
+}

test/parallel/test-crypto-hmac.js

@@ -7,13 +7,6 @@ if (!common.hasCrypto) {
 const assert = require('assert');
 const crypto = require('crypto');
 
-{
-  const Hmac = crypto.Hmac;
-  const instance = crypto.Hmac('sha256', 'Node');
-  assert(instance instanceof Hmac, 'Hmac is expected to return a new instance' +
-                                   ' when called without `new`');
-}
-
 assert.throws(
   () => crypto.createHmac(null),
   {
@@ -411,41 +404,6 @@ assert.strictEqual(
   crypto.createHmac('sha256', 'w00t').digest('ucs2'),
   crypto.createHmac('sha256', 'w00t').digest().toString('ucs2'));
 
-// Check initialized -> uninitialized state transition after calling digest().
-{
-  const expected =
-      '\u0010\u0041\u0052\u00c5\u00bf\u00dc\u00a0\u007b\u00c6\u0033' +
-      '\u00ee\u00bd\u0046\u0019\u009f\u0002\u0055\u00c9\u00f4\u009d';
-  {
-    const h = crypto.createHmac('sha1', 'key').update('data');
-    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(expected, 'latin1'));
-    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(''));
-  }
-  {
-    const h = crypto.createHmac('sha1', 'key').update('data');
-    assert.strictEqual(h.digest('latin1'), expected);
-    assert.strictEqual(h.digest('latin1'), '');
-  }
-}
-
-// Check initialized -> uninitialized state transition after calling digest().
-// Calls to update() omitted intentionally.
-{
-  const expected =
-      '\u00f4\u002b\u00b0\u00ee\u00b0\u0018\u00eb\u00bd\u0045\u0097' +
-      '\u00ae\u0072\u0013\u0071\u001e\u00c6\u0007\u0060\u0084\u003f';
-  {
-    const h = crypto.createHmac('sha1', 'key');
-    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(expected, 'latin1'));
-    assert.deepStrictEqual(h.digest('buffer'), Buffer.from(''));
-  }
-  {
-    const h = crypto.createHmac('sha1', 'key');
-    assert.strictEqual(h.digest('latin1'), expected);
-    assert.strictEqual(h.digest('latin1'), '');
-  }
-}
-
 {
   assert.throws(
     () => crypto.createHmac('sha7', 'key'),
@@ -460,13 +418,3 @@ assert.strictEqual(
     crypto.createHmac('sha256', keyObject).update('foo').digest(),
   );
 }
-
-{
-  crypto.Hmac('sha256', 'Node');
-  common.expectWarning({
-    DeprecationWarning: [
-      ['crypto.Hmac constructor is deprecated.',
-       'DEP0181'],
-    ]
-  });
-}