Hi Guys I’m trying to extract a public key modolous/ exponent from aws encryption library, I’m able to extract it via another language but I’m facing a major blocker for javascript.
The publickey decoded has to be in ASN.l base64 value appreciate if anyone can provide me guidance, I’ve look up relevant url [https://www.example-code.com/nodejs/rsa_key_modulus.asp](https://www.example-code.com/nodejs/rsa_key_modulus.asp) extraction process already but it doesn’t seem to work for me.
As well as sof, answers provided is not in javascript.
[https://stackoverflow.com/questions/3116907/rsa-get-exponent-and-modulus-given-a-public-key](https://stackoverflow.com/questions/3116907/rsa-get-exponent-and-modulus-given-a-public-key)
/**Extract Modulous and exponent ASN.l from publickey */
import {
RawRsaKeyringNode,
buildClient,
CommitmentPolicy,
} from ‘@aws-crypto/client-node’;
import { generateKeyPair } from ‘crypto’;
import { promisify } from ‘util’;
const generateKeyPairAsync = promisify(generateKeyPair);
/* This builds the client with the REQUIRE_ENCRYPT_REQUIRE_DECRYPT commitment policy,
* which enforces that this client only encrypts using committing algorithm suites
* and enforces that this client
* will only decrypt encrypted messages
* that were created with a committing algorithm suite.
* This is the default commitment policy
* if you build the client with `buildClient()`.
*/
const { encrypt, decrypt } = buildClient(
CommitmentPolicy.REQUIRE_ENCRYPT_REQUIRE_DECRYPT,
);
/**
* This function is an example of using the RsaKeyringNode
* to encrypt and decrypt a simple string
*/
export async function rsaTest() {
/* You need to specify a name
* and a namespace for raw encryption key providers.
* The name and namespace that you use in the decryption keyring *must* be an exact,
* *case-sensitive* match for the name and namespace in the encryption keyring.
*/
const keyName = ‘rsa-name’;
const keyNamespace = ‘rsa-namespace’;
// Get your key pairs from wherever you store them.
const rsaKey = await generateRsaKeys();
const { publicKey, privateKey } = await generateRsaKeys();
/**Would like to extract Modulous and exponent ASN.l from publickey here*/
console.log(publicKey);
/* The RSA keyring must be configured with the desired RSA keys
* If you only want to encrypt, only configure a public key.
* If you only want to decrypt, only configure a private key.
*/
const keyring = new RawRsaKeyringNode({ keyName, keyNamespace, rsaKey });
/* Encryption context is a *very* powerful tool for controlling and managing access.
* It is ***not*** secret!
* Encrypted data is opaque.
* You can use an encryption context to assert things about the encrypted data.
* Just because you can decrypt something does not mean it is what you expect.
* For example, if you are are only expecting data from ‘us-west-2’,
* the origin can identify a malicious actor.
* See: https://docs.aws.amazon.com/encryption-sdk/latest/developer-guide/concepts.html#encryption-context
*/
const context = {
stage: ‘demo’,
purpose: ‘simple demonstration app’,
origin: ‘us-west-2’,
};
/* Find data to encrypt. A simple string. */
const cleartext = ‘asdf’;
/* Encrypt the data. */
const { result } = await encrypt(keyring, cleartext, {
encryptionContext: context,
});
/* Decrypt the data. */
const { plaintext, messageHeader } = await decrypt(keyring, result);
/* Grab the encryption context so you can verify it. */
const { encryptionContext } = messageHeader;
/* Verify the encryption context.
* If you use an algorithm suite with signing,
* the Encryption SDK adds a name-value pair to the encryption context that contains the public key.
* Because the encryption context might contain additional key-value pairs,
* do not add a test that requires that all key-value pairs match.
* Instead, verify that the key-value pairs you expect match.
*/
Object.entries(context).forEach(([key, value]) => {
if (encryptionContext[key] !== value)
throw new Error(‘Encryption Context does not match expected values’);
});
/* Return the values so the code can be tested. */
return { plaintext, result, cleartext };
}
/**
* This is a helper function to generate an RSA key pair for testing purposes only.
*/
async function generateRsaKeys() {
const modulusLength = 3072;
const publicKeyEncoding = { type: ‘pkcs1’, format: ‘pem’ };
const privateKeyEncoding = { type: ‘pkcs1’, format: ‘pem’ };
// @ts-ignore
return generateKeyPairAsync(‘rsa’, {
modulusLength,
publicKeyEncoding,
privateKeyEncoding,
});
}