EC
ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE
Node.jsERRORNotableCryptoHIGH confidence

Crypto key object type is invalid for this operation

Production Risk

Prevents signing from occurring; caught at development time if tested.

What this means

Thrown when a crypto.KeyObject is used for an operation that requires a different key type. For example, using a public key where a private key is required (e.g. for signing), or using a secret key where an asymmetric key is required.

Why it happens
  1. 1Passing a public KeyObject to sign() which requires a private key
  2. 2Passing an asymmetric key to createHmac() which requires a secret key
  3. 3Confusing key type (public/private/secret) when constructing crypto operations
How to reproduce

Triggered when a crypto operation validates the key type and finds it does not match the required type.

trigger — this will error
trigger — this will error
const { generateKeyPairSync, createSign } = require('crypto');
const { publicKey } = generateKeyPairSync('rsa', { modulusLength: 2048 });
const sign = createSign('SHA256');
sign.update('data');
sign.sign(publicKey); // throws — needs private key

expected output

Error [ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE]: Invalid key object type public, expected private

Fix

Use the correct key type for each operation

WHEN Always — check the API docs for required key type

Use the correct key type for each operation
const { generateKeyPairSync, createSign, createVerify } = require('crypto');
const { privateKey, publicKey } = generateKeyPairSync('rsa', { modulusLength: 2048 });

// Sign with private key
const sign = createSign('SHA256');
sign.update('data');
const signature = sign.sign(privateKey);

// Verify with public key
const verify = createVerify('SHA256');
verify.update('data');
console.log(verify.verify(publicKey, signature));

Why this works

Using the correct key type (private for signing, public for verifying) satisfies the type check.

Code examples
Triggerjs
const { generateKeyPairSync, createSign } = require('crypto');
const { publicKey } = generateKeyPairSync('rsa', { modulusLength: 2048 });
const sign = createSign('SHA256');
sign.update('data');
sign.sign(publicKey); // throws — needs private key  // this triggers ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE
Handle in try/catchjs
try {
  // operation that may throw ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE
  riskyOperation()
} catch (err) {
  if (err.code === 'ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE') {
    console.error('ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE:', err.message)
  } else {
    throw err
  }
}
Defensive pattern to avoid itjs
// Validate inputs before calling the operation
function safe_err_crypto_invalid_key_object_type(...args) {
  // validate args here
  return performOperation(...args)
}
What not to do

✕ Use public keys for signing or secret keys for asymmetric operations

Each crypto operation has strict key type requirements enforced by the API.

Same error in other languages
TypeErrorin Python→
Sources
Official documentation ↗

Node.js Error Codes Documentation

Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev

← All Node.js errors