The following method is deprecated
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA", "AndroidKeyStore");
KeyPairGeneratorSpec spec = new KeyPairGeneratorSpec.Builder(this)
.setAlias(alias)
.setSubject(new X500Principal("CN=Sample Name, O=Android Authority"))
.setSerialNumber(BigInteger.ONE)
.setStartDate(start.getTime())
.setEndDate(end.getTime())
.build();
generator.initialize(spec);
Replaced, I looked like this:
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA", "AndroidKeyStore");
generator.initialize(new KeyGenParameterSpec.Builder
(alias, KeyProperties.PURPOSE_SIGN)
.setDigests(KeyProperties.DIGEST_SHA256)
.setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PKCS1)
.build());
Although I can use this to create an entry in keypair and encrypt the value, I cannot decrypt it.
public void encryptString(String alias) {
try {
KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry)keyStore.getEntry(alias, null);
RSAPublicKey publicKey = (RSAPublicKey) privateKeyEntry.getCertificate().getPublicKey();
String initialText = startText.getText().toString();
if(initialText.isEmpty()) {
Toast.makeText(this, "Enter text in the 'Initial Text' widget", Toast.LENGTH_LONG).show();
return;
}
Cipher inCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidKeyStoreBCWorkaround");
inCipher.init(Cipher.ENCRYPT_MODE, publicKey);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
CipherOutputStream cipherOutputStream = new CipherOutputStream(
outputStream, inCipher);
cipherOutputStream.write(initialText.getBytes("UTF-8"));
cipherOutputStream.close();
byte [] vals = outputStream.toByteArray();
encryptedText.setText(Base64.encodeToString(vals, Base64.DEFAULT));
} catch (Exception e) {
Toast.makeText(this, "Exception " + e.getMessage() + " occured", Toast.LENGTH_LONG).show();
Log.e(TAG, Log.getStackTraceString(e));
}
}
public void decryptString(String alias) {
try {
KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry)keyStore.getEntry(alias, null);
Cipher output = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidKeyStoreBCWorkaround");
output.init(Cipher.DECRYPT_MODE, privateKeyEntry.getPrivateKey());
String cipherText = encryptedText.getText().toString();
CipherInputStream cipherInputStream = new CipherInputStream(
new ByteArrayInputStream(Base64.decode(cipherText, Base64.DEFAULT)), output);
ArrayList<Byte> values = new ArrayList<>();
int nextByte;
while ((nextByte = cipherInputStream.read()) != -1) {
values.add((byte)nextByte);
}
byte[] bytes = new byte[values.size()];
for(int i = 0; i < bytes.length; i++) {
bytes[i] = values.get(i).byteValue();
}
String finalText = new String(bytes, 0, bytes.length, "UTF-8");
decryptedText.setText(finalText);
} catch (Exception e) {
Toast.makeText(this, "Exception " + e.getMessage() + " occured", Toast.LENGTH_LONG).show();
Log.e(TAG, Log.getStackTraceString(e));
}
the decryptfollowing command is executed in the method :
Cipher output = Cipher.getInstance("RSA/ECB/PKCS1Padding", "AndroidKeyStoreBCWorkaround");
output.init(Cipher.DECRYPT_MODE, privateKeyEntry.getPrivateKey());
with
java.security.InvalidKeyException: Keystore operation failed
I think this is due to the fact that KeyGenParamaterSpec.Builder has incorrect conditions, similar to the fact that the encrypted Cipher types are invalid strings, the same is in the decryption function.
But all this can be traced back to using the new KeygenParameterSpec.Builder, since using the old obsolete method allows me to encrypt and decrypt.
How to fix?