#Java: #RC4 + Base64

import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

/*...*/

public static String encrypt(String key, String clearText) throws Exception{
    Cipher c = Cipher.getInstance(RC4_NAME);
    Key mainKey = new SecretKeySpec(key.getBytes(), "RC4");
    c.init(Cipher.ENCRYPT_MODE, mainKey);
    byte[] encVal = c.doFinal(clearText.getBytes(UNICODE));
    String encryptedValue =  Base64.encodeToString(encVal, false);
    return encryptedValue;
}

public static String decrypt(String key, String encryptedData) throws Exception {
    Cipher c = Cipher.getInstance(RC4_NAME);
    Key mainKey = new SecretKeySpec(key.getBytes(), "RC4");
    c.init(Cipher.DECRYPT_MODE, mainKey);
    byte[] decordedValue = Base64.decode(encryptedData);
    byte[] decValue = c.doFinal(decordedValue);
    String decryptedValue = new String(decValue, UNICODE);
    return decryptedValue;
}