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POCreating cipher key from random text on Android
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  1. POCreating cipher key from random text on Android
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    copied!<p>I'm having a little problem. In my app I need to create a key for AES encryption from String written by a user, and I have no idea how to do it. For example: user writes: "abscde" and I need to some how change it to an AES key. Here is my code. It works but only with key provided in hex, like "000102030405060708090A0B0C0D0E0F".</p> <pre><code> public static String encrypt(String text, String key){ String mess="error"; try{ byte[] encodedText=text.getBytes(Charset.forName("UTF-8")); byte[] keyData=hexStringToByte(key); SecretKeySpec sKey=new SecretKeySpec(keyData, "AES"); Cipher encryptionCypher=Cipher.getInstance("AES/CBC/PKCS5Padding"); final int blocks=encryptionCypher.getBlockSize(); final byte[] ivData=new byte[blocks]; final SecureRandom rnd=new SecureRandom(); rnd.nextBytes(ivData); final IvParameterSpec iv=new IvParameterSpec(ivData); encryptionCypher.init(Cipher.ENCRYPT_MODE, sKey,iv); final byte[] encryptedMessage=encryptionCypher.doFinal(encodedText); final byte[] ivAndMessage=new byte[ivData.length+encryptedMessage.length]; System.arraycopy(ivData, 0, ivAndMessage, 0, blocks); System.arraycopy(encryptedMessage, 0, ivAndMessage, blocks, encryptedMessage.length); final String finalMessage=Base64.encodeToString(ivAndMessage, 0); mess=finalMessage; } catch (IllegalBlockSizeException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (BadPaddingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (InvalidAlgorithmParameterException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (NoSuchPaddingException e) { // TODO Auto-generated catch block e.printStackTrace(); } return mess; } </code></pre>
 

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