去年，我用 C# 编写了一次性密码 (OTP) 生成器。现在我需要在 Java 中使用 OTP 生成器，但我在 Java 中找不到等效的函数。
这是我去年写的代码：（我知道这个 OTP 的安全性很低，但我不需要防弹的）
SHA1CryptoServiceProvider hash = new SHA1CryptoServiceProvider(); //first hash with sha1
byte[] hashPass = hash.ComputeHash(Encoding.ASCII.GetBytes(pass)); //pass is entered by user
HMACMD5 hma = new HMACMD5(hashPass); // use the hashed value as a key to hmac
OTPass = hma.ComputeHash(Encoding.ASCII.GetBytes(email + Counter(email)));// generate OTPass, Counter(email) is the counter of the user taken from database
increaseCounter(email); // updating the counter
this.SetLog(this.GetLog() + Environment.NewLine + "OTPass Generated: " + BitConverter.ToString(OTPass)); // OTP
这是我尝试将 C# 转换为的 Java 代码：（这只是 SHA1 部分，我找不到如何用 Java 编写 HMAC-MD5）
import java.io.*;
import java.security.*;
public class otp {
/**
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
System.out.println("Please enter your username:");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String username = br.readLine();
System.out.println("Please enter your password:");
String password = br.readLine();
try {
MessageDigest md = MessageDigest.getInstance("SHA1");
String input = password;
md.update(input.getBytes());
byte[] output = md.digest();
System.out.println();
System.out.println("SHA1(\""+input+"\") =");
System.out.println(" "+bytesToHex(output));
} catch (Exception e) {
System.out.println("Exception: "+e);
}
}
public static String bytesToHex(byte[] b) {
char hexDigit[] = {'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
StringBuffer buf = new StringBuffer();
for (int j=0; j<b.length; j++) {
buf.append(hexDigit[(b[j] >> 4) & 0x0f]);
buf.append(hexDigit[b[j] & 0x0f]);
}
return buf.toString();
}
}
感谢帮助