RSA encryption :InvalidKeyException: invalid key format

Question

Hi All,

I have to read pem key files to get RSA Public key,and then use them to encrypt. I can do this using openssl and convert pem file to der file. and then load my key using X509EncodedKeySpec and PKCS8EncodedKeySpec. But I don't want to do this because pem is the user key exchange format. user can register it's own key can like this :

--BEGIN PUBLIC KEY-- MIGeMA0GCSqGSIb3DQEBAQUAA4GMADCBiAKBgGi0/vKrSIIQMOm4atiw+2s8tSojOKHsWJU3oPTm

b1a5UQIH7CM3NgtLvUF5DqhsP2jTqgYSsZSl+W2RtqCFTavZTWvmc0UsuK8tTzvnCXETsnpjeL13

Hul9JIpxZVej7b6KxgyxFAhuz2AGscvCXnepElkVh7oGOqkUKL7gZSD7AgMBAAE=

--END PUBLIC KEY--

and this key is store in a database in this format...

Here is the code I have tried..

File pubKeyFile=new File("D:/public_key.pem");
DataInputStream dis = new DataInputStream(new FileInputStream(pubKeyFile));
byte[] pubKeyBytes = new byte[(int)pubKeyFile.length()];
dis.readFully(pubKeyBytes);
dis.close();
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
X509EncodedKeySpec pubSpec = new X509EncodedKeySpec(pubKeyBytes);
RSAPublicKey pubKey = (RSAPublicKey) keyFactory.generatePublic(pubSpec);

I am getting exception as

java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: invalid key format

As I am completely new to encryption concepts can anyone please help me to solve this exception?

Many thanks.

Answer 1

With bouncycastle, it would be done this way:

CertificateFactory cf = CertificateFactory.getInstance("X509", "BC");
InputStream is = new FileInputStream("D:/public_key.pem");
X509Certificate certificate = (X509Certificate) cf.generateCertificate(is);
is.close();
RSAPublicKey pubKey = (RSAPublicKey)certificate.getPublicKey();