我构建了一个必须具有 Google 身份验证器代码（密码）才能访问它的 Android 应用程序。我生成16个字符的序列码的问题但是当我尝试编写验证码时，应用程序总是告诉我这是错误的验证码......手机和电脑的时间是一样的，所以我不知道为什么我不工作...
这是我使用的一些代码：
`
//Base32.java
private static final Base32 INSTANCE =
new Base32("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"); // RFC 4668/3548
static Base32 getInstance() {
return INSTANCE;
}
// 32 alpha-numeric characters.
private String ALPHABET;
private char[] DIGITS;
private int MASK;
private int SHIFT;
private HashMap<Character, Integer> CHAR_MAP;
static final String SEPARATOR = "-";
protected Base32(String alphabet) {
this.ALPHABET = alphabet;
DIGITS = ALPHABET.toCharArray();
MASK = DIGITS.length - 1;
SHIFT = Integer.numberOfTrailingZeros(DIGITS.length);
CHAR_MAP = new HashMap<Character, Integer>();
for (int i = 0; i < DIGITS.length; i++) {
CHAR_MAP.put(DIGITS[i], i);
}
}
public static byte[] decode(String encoded) throws DecodingException {
return getInstance().decodeInternal(encoded);
}
protected byte[] decodeInternal(String encoded) throws DecodingException {
// Remove whitespace and separators
encoded = encoded.trim().replaceAll(SEPARATOR, "").replaceAll(" ", "");
// Canonicalize to all upper case
encoded = encoded.toUpperCase();
if (encoded.length() == 0) {
return new byte[0];
}
int encodedLength = encoded.length();
int outLength = encodedLength * SHIFT / 8;
byte[] result = new byte[outLength];
int buffer = 0;
int next = 0;
int bitsLeft = 0;
for (char c : encoded.toCharArray()) {
if (!CHAR_MAP.containsKey(c)) {
throw new DecodingException("Illegal character: " + c);
}
buffer <<= SHIFT;
buffer |= CHAR_MAP.get(c) & MASK;
bitsLeft += SHIFT;
if (bitsLeft >= 8) {
result[next++] = (byte) (buffer >> (bitsLeft - 8));
bitsLeft -= 8;
}
}
// We'll ignore leftover bits for now.
//
// if (next != outLength || bitsLeft >= SHIFT) {
// throw new DecodingException("Bits left: " + bitsLeft);
// }
return result;
}
public static String encode(byte[] data) {
return getInstance().encodeInternal(data);
}
protected String encodeInternal(byte[] data) {
if (data.length == 0) {
return "";
}
// SHIFT is the number of bits per output character, so the length of the
// output is the length of the input multiplied by 8/SHIFT, rounded up.
if (data.length >= (1 << 28)) {
// The computation below will fail, so don't do it.
throw new IllegalArgumentException();
}
int outputLength = (data.length * 8 + SHIFT - 1) / SHIFT;
StringBuilder result = new StringBuilder(outputLength);
int buffer = data[0];
int next = 1;
int bitsLeft = 8;
while (bitsLeft > 0 || next < data.length) {
if (bitsLeft < SHIFT) {
if (next < data.length) {
buffer <<= 8;
buffer |= (data[next++] & 0xff);
bitsLeft += 8;
} else {
int pad = SHIFT - bitsLeft;
buffer <<= pad;
bitsLeft += pad;
}
}
int index = MASK & (buffer >> (bitsLeft - SHIFT));
bitsLeft -= SHIFT;
result.append(DIGITS[index]);
}
return result.toString();
}
@Override
// enforce that this class is a singleton
public Object clone() throws CloneNotSupportedException {
throw new CloneNotSupportedException();
}
static class DecodingException extends Exception {
public DecodingException(String message) {
super(message);
}
}
}`
//CheckCode.java
...public void onClick(View v) {
String codeDigited=ed.getText().toString();
Log.d("codeDigited", codeDigited);
try {
if(check_code(codeDigited, 0, 0)==true){
Intent step = new Intent(this, GoogleAuthenticator.class);
startActivity(step);
}else{
info.setText("passwords doesn't match! oh noes!");
}
} catch (InvalidKeyException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (DecodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private static boolean check_code(String secret, long code, long t)
throws NoSuchAlgorithmException, InvalidKeyException, DecodingException {
//Base32 codec = new Base32(secret);
byte[] decodedKey = Base32.decode(secret);
// Window is used to check codes generated in the near past.
// You can use this value to tune how far you're willing to go.
int window = 30;
for (int i = -window; i <= window; ++i) {
long hash = verify_code(decodedKey, t + i);
if (hash == code) {
System.out.println("right");
return true;
}
}
System.out.println("OOOOOOOps codec.decode(secret): "+decodedKey.toString());
// The validation code is invalid.
return false;
}
private static int verify_code(byte[] key, long t)
throws NoSuchAlgorithmException, InvalidKeyException {
byte[] data = new byte[8];
long value = t;
for (int i = 8; i-- > 0; value >>>= 8) {
data[i] = (byte) value;
}
SecretKeySpec signKey = new SecretKeySpec(key, "HmacSHA1");
Mac mac = Mac.getInstance("HmacSHA1");
mac.init(signKey);
byte[] hash = mac.doFinal(data);
int offset = hash[20 - 1] & 0xF;
// We're using a long because Java hasn't got unsigned int.
long truncatedHash = 0;
for (int i = 0; i < 4; ++i) {
truncatedHash <<= 8;
// We are dealing with signed bytes:
// we just keep the first byte.
truncatedHash |= (hash[offset + i] & 0xFF);
}
truncatedHash &= 0x7FFFFFFF;
truncatedHash %= 1000000;
return (int) truncatedHash;
}
codeDigited 是我从 Google authentificator App 获取的验证码，但我不知道为什么该代码不起作用