Get RSA Public or Private Key from KeyPair Generation Flutter - dart

Question

I have added pointycastle and generated a keypair, encrypting the trial "Hello World" string. From this, I want to get the values of the Private and Public Key. Is there anywhere they are stored, because whenever I try to print the values of keyPair.privateKey, it returns Instance of 'RSAPrivateKey.
Here is the code I used
var keyParams = new RSAKeyGeneratorParameters(new BigInt.from(65537), 2048, 5);
var secureRandom = new FortunaRandom();
var random = new Random.secure();
List<int> seeds = [];
for (int i = 0; i < 32; i++) {
seeds.add(random.nextInt(255));
}
secureRandom.seed(new KeyParameter(new Uint8List.fromList(seeds)));
var rngParams = new ParametersWithRandom(keyParams, secureRandom);
var k = new RSAKeyGenerator();
k.init(rngParams);
var keyPair = k.generateKeyPair();
var cipher = new RSAEngine()..init( true, new PublicKeyParameter<RSAPublicKey>(keyPair.publicKey));
print("pubkey: ${keyPair.publicKey.toString()}");
var cipherText = cipher.process(new Uint8List.fromList("Hello World".codeUnits));
print("Encrypted: ${new String.fromCharCodes(cipherText)}");
cipher.init( false, new PrivateKeyParameter<RSAPrivateKey>(keyPair.privateKey));
//cipher.init( false, new PrivateKeyParameter(keyPair.privateKey) )
var decrypted = cipher.process(cipherText);
print("Decrypted: ${new String.fromCharCodes(decrypted)}");

Answer 1

Make sure to import package:pointycastle/asymmetric/api.dart, then use:
var k = RSAKeyGenerator()..init(rngParams);
AsymmetricKeyPair<PublicKey, PrivateKey> keyPair = k.generateKeyPair();
RSAPrivateKey privateKey = keyPair.privateKey;
RSAPublicKey publicKey = keyPair.publicKey;
print(privateKey.d); // prints private exponent
print(publicKey.n); // prints modulus
Recreate from the individual parts:
RSAPrivateKey foo = RSAPrivateKey(
privateKey.n,
privateKey.d,
privateKey.p,
privateKey.q,
);
RSAPublicKey bar = RSAPublicKey(publicKey.n, publicKey.e);