Java: Converting between Key type and String

Question

Is it possible to take a public key that I have generated, convert it into a string, reverse the process and use it as a key again?

    generator = KeyPairGenerator.getInstance("RSA");
    generator.initialize(2048);

    KeyPair keyPair = generator.generateKeyPair();

    RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
    RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

Then convert this to a string:

String public = someMethod(publicKey)

and then Reverse it at a later time:

RSAPublicKey newPublicKey = someMethod(public)

Udith Gunaratna · Accepted Answer · 2019-09-23 06:03:25Z

3

You can convert the Public Key to a String as follows.

String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());

Then that String can be converted back to a public key as follows.

byte[] publicKeyBytes = Base64.getDecoder().decode(publicKeyString);
X509EncodedKeySpec spec = new X509EncodedKeySpec(publicKeyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey2 = keyFactory.generatePublic(spec);

edited Sep 23, 2019 at 6:03

answered Sep 23, 2019 at 5:00

Udith Gunaratna

2,1211 gold badge13 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user207421 Over a year ago

Surely the base64-decoder accepts a String argument?

Collectives™ on Stack Overflow

Java: Converting between Key type and String

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related