10

我现在正在制作 RSA 消息认证软件。过程如下：

  1. 使用 A 的私钥（1024 位）对消息进行签名
  2. 使用 A 的公钥（1024 位）验证消息

#1 代码（如下）工作正常并生成以下结果：

5554c9a9f6838b6cf40d9dbfbab3d90ea27aa6434ed095d289c13c2624617993ad99161ac265276d150510c176341d8ab8600d08b7353286d465e6bd3370a6fd8dd3ffb82916f612fd6dcee5e654ed801cfca6b6d2d5d6dc99ff7921b615abdf62eb67db1f71e6a6ea70012fd35e7cefa1a8d3aab7614c47746cfe1fc2bc875b

但是 #2 代码显示以下错误：

javax.crypto.IllegalBlockSizeException: Data must not be longer than 128 bytes

我认为#1 中的行会Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); 生成 2048 位（256 字节）的结果。也许这就是问题所在……记住我使用的是 1024 位私钥。

那么#1 代码如何生成 128 字节的结果呢？

1.SignMail.java

public class SignMail {

    static {
        Security.addProvider(new org.spongycastle.jce.provider.BouncyCastleProvider());
    }

    public static String sign(String userOriginalMessage) throws Exception {

        PEMReader userPrivateKey = new PEMReader(
          new InputStreamReader(
             new FileInputStream(Environment.getExternalStorageDirectory()+"/pkcs10priv.key")));

        KeyPair keyPair = (KeyPair)userPrivateKey.readObject();

        byte[] cipherText;
        //modified by JEON 20130817
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        //encrypt the message using private key
        cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPrivate());
        cipherText = cipher.doFinal(userOriginalMessage.getBytes());
        return new String(Hex.encode(cipherText));

    }


}

2.UserSMSVerifier.java

public class UserSMSVerifier {

static String signedMail;

static {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
}


public static String messageGenarator(
        String UserCert,
        String origninalMessage         
        ) throws Exception{

    InputStream userCertStream = new ByteArrayInputStream(UserCert.getBytes("UTF-8"));

    PEMReader userCerti = new PEMReader(
              new InputStreamReader(
                      userCertStream));



    //KeyPair userPrivate = (KeyPair)userPrivateKey.readObject();
    X509Certificate userCert = (X509Certificate)userCerti.readObject();


    byte[] dectyptedText = null;
    // decrypt the text using the private key
    //modified by JEON 20130817
    //Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
    cipher.init(Cipher.DECRYPT_MODE, userCert.getPublicKey());
    dectyptedText = cipher.doFinal(origninalMessage.getBytes());

    String result = new String(dectyptedText, Charset.forName("UTF-8"));
    return result;

}


}

#2 代码由以下 JSP 执行

#3 messageVeri.JSP

<%@ page language="java" contentType="text/html; charset=euc-kr" %>

<%@ page session = "true" %>

<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.SQLException" %>
<%@ page import="java.sql.ResultSet" %>

<%@ page import="myPackage.UserSMSVerifier" %>


<%
    request.setCharacterEncoding("euc-kr");

    String userID = request.getParameter("sender");
    String encryptedSMS = request.getParameter("encryptedSMS");

    //String sql = "select user_id, user_pw from testca.testca_init where user_id=? and user_pw=?";
    //String sql = "update testca.testca_init set pkcs10request = '"+pkcs10request_new+"' where user_id='user1'";
    String sql = "select * from testca.testca_init where user_id='" + userID + "'";

    Class.forName("com.mysql.jdbc.Driver");

    Connection conn = null;
    PreparedStatement pstmt = null;

    Statement stmt = null;
    ResultSet rs = null;

    String jdbcDriver = "jdbc:mysql://localhost:3306/";
    String dbUser = "root";
    String dbPass = "fo.......t";


    try{
        conn = DriverManager.getConnection(jdbcDriver, dbUser, dbPass);
        stmt = conn.createStatement();
        //stmt.executeUpdate(sql);
        rs=stmt.executeQuery(sql);
        while(rs.next()){
        //rs=stmt.executeQuery(sql);
        String userCertificate=rs.getString("certificate");
        UserSMSVerifier.messageGenarator(userCertificate, encryptedSMS);
        }



    }catch(Exception ex){out.print("Error 2: " +ex);}
    /*
    if(rs.next())
    {
        //session.setAttribute("userID", userID);
        out.print("Insert Succeed!");
        out.println();
        //out.print("Welcome!" + " " + session.getAttribute("userID"));
    }
    else
    {
        out.print("failed to login!");
        //session.invalidate();
    }
    */

%>
4

5 回答 5

16

您的签名字符串包含 256 个字符，但是这是十六进制的，实际上代表 128个字节。

在验证签名之前，您必须将其转换回字节数组。这不是通过someString.getBytes()而是通过DatatypeConverter.parseHexBinary(someString)（或您喜欢 Google 的任何其他方法）实现的。

另外，我强烈建议您在签署消息时使用Signature类而不是类。Cipher目前，您的代码只能处理长度小于 128 字节的消息（实际上，由于填充而更小）。相反，您应该在签名之前对消息进行哈希处理（例如使用SHA256withRSA机制）。

于 2013-08-19T08:28:39.117 回答
2

正如邓肯所说，你需要像 DateTypeConverter 这样的东西。

我使用Base64.getDecoder().decode(encodedString)，它返回 128 字节数组。

当我使用encodedString.getBytes() 时，它返回172 字节数组。

顺便说一句，我有 1024 位 RSA 密钥。

于 2016-11-25T11:03:24.910 回答
2

首先将文本转换为十六进制，然后对其进行加密，加密后您可以将十六进制转换为字符串。

public static String toHex(String text)
{
    return String.format("%040x", new BigInteger(1, text.getBytes()));
}

public static byte[] hexToBytes(String hex)
{
    int l = hex.length();
    byte[] data = new byte[l/2];

    for (int i = 0; i < l; i += 2)
    {
        data[i/2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4) + Character.digit(hex.charAt(i+1), 16));
    }

    return data;
}

public static String hexToStringA(String hex)
{
    return new String(hexToBytes(hex));
}
于 2018-05-15T06:16:58.243 回答
0

您需要通过 publicKey 拆分数据

int keyLength = publicKey.getModulus().bitLength() / 16;
String[] datas = splitString(data, keyLength - 11);
String mi = "";
        //如果明文长度大于模长-11则要分组加密
for (String s : datas) {
            mi += bcd2Str(cipher.doFinal(s.getBytes()));
}
return mi;


public static String bcd2Str(byte[] bytes) {
    char temp[] = new char[bytes.length * 2], val;

    for (int i = 0; i < bytes.length; i++) {
        val = (char) (((bytes[i] & 0xf0) >> 4) & 0x0f);
        temp[i * 2] = (char) (val > 9 ? val + 'A' - 10 : val + '0');

        val = (char) (bytes[i] & 0x0f);
        temp[i * 2 + 1] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
    }
    return new String(temp);
}
于 2016-07-19T03:24:15.110 回答
0

这是代码：

     EncDecProcessor ac = new EncDecProcessor();
     PublicKey publicKey = ac.getPublic(keyPath);
     this.cipher.init(Cipher.DECRYPT_MODE, publicKey);
     byte[] b = new byte[2048];
     b = msg.getBytes("UTF-8");
     byte[] byteStr = Base64.decodeBase64(b);
     String Str = new String(cipher.doFinal(byteStr), "UTF-8");

     return Str;
于 2019-03-05T07:26:19.597 回答