diff --git a/modules/serialize/src/deserialize_factory.ts b/modules/serialize/src/deserialize_factory.ts
index 1c1b0085f..b4c29cf33 100644
--- a/modules/serialize/src/deserialize_factory.ts
+++ b/modules/serialize/src/deserialize_factory.ts
@@ -197,7 +197,7 @@ export function deserializeFactory<Suite extends AlgorithmSuite> (
    * @param encodedEncryptionContext Uint8Array
    */
   function decodeEncryptionContext (encodedEncryptionContext: Uint8Array) {
-    const encryptionContext: EncryptionContext = {}
+    const encryptionContext: EncryptionContext = Object.create(null)
     /* Check for early return (Postcondition): The case of 0 length is defined as an empty object. */
     if (!encodedEncryptionContext.byteLength) {
       return encryptionContext
diff --git a/modules/serialize/test/deserialize_factory.test.ts b/modules/serialize/test/deserialize_factory.test.ts
index 1e5c5850d..c0bf67e18 100644
--- a/modules/serialize/test/deserialize_factory.test.ts
+++ b/modules/serialize/test/deserialize_factory.test.ts
@@ -78,6 +78,17 @@ describe('deserializeFactory:decodeEncryptionContext', () => {
     expect(test).to.have.property('information')
       .and.to.eql('\u00bd + \u00bc = \u00be')
   })
+
+  it('Keys may be properties of Object.prototype, decodeEncryptionContext has to succeed', () => {
+    const { decodeEncryptionContext } = deserializeFactory(toUtf8, WebCryptoAlgorithmSuite)
+
+    /* hasOwnProperty test vector */
+    const encryptionContext = fixtures.hasOwnPropertyEncryptionContext().slice(2)
+
+    const test = decodeEncryptionContext(encryptionContext)
+    expect(test).to.have.property('hasOwnProperty')
+      .and.to.eql('arbitraryValue')
+  })
 })
 
 describe('deserializeFactory:deserializeEncryptedDataKeys', () => {
diff --git a/modules/serialize/test/fixtures.ts b/modules/serialize/test/fixtures.ts
index 12efbc33e..7ce264ace 100644
--- a/modules/serialize/test/fixtures.ts
+++ b/modules/serialize/test/fixtures.ts
@@ -77,6 +77,10 @@ export function duplicateKeysEncryptionContext () {
   return new Uint8Array([ 0, 43, 0, 4, 0, 11, 105, 110, 102, 111, 114, 109, 97, 116, 105, 111, 110, 0, 12, 194, 189, 32, 43, 32, 194, 188, 32, 61, 32, 194, 190, 0, 11, 105, 110, 102, 111, 114, 109, 97, 116, 105, 111, 110, 0, 12, 194, 189, 32, 43, 32, 194, 188, 32, 61, 32, 194, 190, 0, 4, 115, 111, 109, 101, 0, 6, 112, 117, 98, 108, 105, 99, 0, 4, 115, 111, 109, 101, 0, 6, 112, 117, 98, 108, 105, 99 ])
 }
 
+export function hasOwnPropertyEncryptionContext () {
+  return new Uint8Array([ 0, 34, 0, 1, 0, 14, 104, 97, 115, 79, 119, 110, 80, 114, 111, 112, 101, 114, 116, 121, 0, 14, 97, 114, 98, 105, 116, 114, 97, 114, 121, 86, 97, 108, 117, 101 ])
+}
+
 export function basicFrameIV () {
   return new Uint8Array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1])
 }