Write me some javascript that takes a Base64 encoded private key, extracts the public key from it, then encrypts a JWE with a given string using the public key using RSAES-PKCS1-v1\_5 key encryption and AES\_256\_CBC\_HMAC\_SHA\_512 content encryption
user
to implement this functionality, first, ensure that you have the necessary libraries installed. you'll need the following npm packages: `jsonwebtoken`, `jose-node-esm-runtime`, and `crypto`. run the following command to install them:

```bash
npm install jsonwebtoken@9.0.4 jose-node-esm-runtime@3.21.1 crypto@1.0.1
```

here's a sample javascript code that performs the desired actions:

```javascript
import jwt from 'jsonwebtoken';
import { pem2jwk } from 'pem-jwk';
import crypto from 'crypto';
import { 
  jwe, 
  jwk, 
  flattenedencrypt, 
  errors, 
  parsex509der 
} from 'jose-node-esm-runtime';

async function decodeprivatekey(base64privatekey) {
  const privatekeyder = buffer.from(base64privatekey, 'base64');
  const privatekeypem = `-----begin private key-----\n${privatekeyder.tostring('base64')}-----end private key-----`;
  return privatekeypem;
}

async function extractpublickey(privatekeypem) {
  const key = pem2jwk(privatekeypem);
  const publickey = {
    kty: key.kty,
    n: key.n,
    e: key.e,
  };
  const publickeyjwk = jwk.askey(publickey);
  return publickeyjwk;
}

async function encryptjwe(publickey, payload) {
  const encrypter = new flattenedencrypt(payload);
  encrypter.setprotectedheader({ alg: 'rsa1_5', enc: 'a256cbc-hs512' });
  const jwe = await encrypter.encrypt(publickey);
  return jwe;
}

(async () => {
  try {
    const privatekeybase64 = '...'; // your base64-encoded private key
    const privatekeypem = await decodeprivatekey(privatekeybase64);
    const publickeyjwk = await extractpublickey(privatekeypem);
  
    const payload = 'hello, world!'; // your text to encrypt
    const jwe = await encryptjwe(publickeyjwk, payload);
    console.log(jwe);
  } catch (err) {
    console.error('error:', err.message);
  }
})();
```

replace `...` with a base64-encoded private key. the code first decodes the base64-encoded private key and extracts the public key from it. then, it creates and encrypts a jwe using the public key using rsaes-pkcs1-v1_5 key encryption and aes_256_cbc_hmac_sha_512 content encryption.
assistant
To implement this functionality, first, ensure that you have the necessary libraries installed. You'll need the following npm packages: `jsonwebtoken`, `jose-node-esm-runtime`, and `crypto`. Run the following command to install them:

```bash
npm install jsonwebtoken@9.0.4 jose-node-esm-runtime@3.21.1 crypto@1.0.1
```

Here's a sample JavaScript code that performs the desired actions:

```javascript
import jwt from 'jsonwebtoken';
import { pem2jwk } from 'pem-jwk';
import crypto from 'crypto';
import { 
  JWE, 
  JWK, 
  FlattenedEncrypt, 
  errors, 
  parseX509DER 
} from 'jose-node-esm-runtime';

async function decodePrivateKey(base64PrivateKey) {
  const privateKeyDer = Buffer.from(base64PrivateKey, 'base64');
  const privateKeyPem = `-----BEGIN PRIVATE KEY-----\n${privateKeyDer.toString('base64')}-----END PRIVATE KEY-----`;
  return privateKeyPem;
}

async function extractPublicKey(privateKeyPem) {
  const key = pem2jwk(privateKeyPem);
  const publicKey = {
    kty: key.kty,
    n: key.n,
    e: key.e,
  };
  const publicKeyJwk = JWK.asKey(publicKey);
  return publicKeyJwk;
}

async function encryptJWE(publicKey, payload) {
  const encrypter = new FlattenedEncrypt(payload);
  encrypter.setProtectedHeader({ alg: 'RSA1_5', enc: 'A256CBC-HS512' });
  const jwe = await encrypter.encrypt(publicKey);
  return jwe;
}

(async () => {
  try {
    const privateKeyBase64 = '...'; // Your Base64-encoded private key
    const privateKeyPem = await decodePrivateKey(privateKeyBase64);
    const publicKeyJwk = await extractPublicKey(privateKeyPem);
  
    const payload = 'Hello, World!'; // Your text to encrypt
    const jwe = await encryptJWE(publicKeyJwk, payload);
    console.log(jwe);
  } catch (err) {
    console.error('Error:', err.message);
  }
})();
```

Replace `...` with a Base64-encoded private key. The code first decodes the Base64-encoded private key and extracts the public key from it. Then, it creates and encrypts a JWE using the public key using RSAES-PKCS1-v1_5 key encryption and AES_256_CBC_HMAC_SHA_512 content encryption.
assistant