Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

Question

hi,
i have to encrypt a simple string with RSA/ECB/OAEPWithSHA1AndMGF1Padding but i have no idea how to start this in java. there are too much security and crypto classes :8
i hope sombody can help me.
Edited by: z3ky on Dec 6, 2007 3:17 PM

Answer 1

First, make sure you have an adequate understanding of cryptography. Java cryptography classes will be hard to understand without it. For example, normally RSA is not used to encrypt (or sign) data directly. If you don't know this or don't know why, then you need to study cryptography more.
I guess the heart of the encryption classes is the Cipher class. Thus, you would start with with something like Cipher rsaCipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding");Next, you need to initialize the cipher object with a mode, a key, and possible other items like an IV, depending on the nature and mode of the encryption algorithm. Here is a sample that generates an RSA Keypair and then initializes the Cipher object:        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        KeyPair kp = kpg.generateKeyPair();
        RSAPublicKey rsaPubkey = (RSAPublicKey) kp.getPublic();
        RSAPrivateKey rsaPrivkey = (RSAPrivateKey) kp.getPrivate();
        rsaCipher.init(Cipher.ENCRYPT_MODE, rsaPubkey);Next, you have to decode your string into a byte array, then encrypt the array, and finally do something with the encrypted data.        String sample = "This is a short string";
        byte[] sampleBytes = sample.getBytes("UTF-8");
        byte[] sampleCipher = rsaCipher.doFinal(sampleBytes);
        System.out.println(Arrays.toString(sampleCipher));