我现在正在制作RSA消息认证软件。过程如下：
＃1代码（如下）工作正常并产生以下结果：
5554c9a9f6838b6cf40d9dbfbab3d90ea27aa6434ed095d289c13c2624617993ad99161ac265276d150510c176341d8ab8600d08b7353286d465e6bd3370a6fd8dd3ffb82916f612fd6dcee5e654ed801cfca6b6d2d5d6dc99ff7921b615abdf62eb67db1f71e6a6ea70012fd35e7cefa1a8d3aab7614c47746cfe1fc2bc875b
然而，＃2代码显示以下错误：
javax.crypto.IllegalBlockSizeException: Data must not be longer than 128 bytes
我认为＃1 Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");中的一行
生成2048位（256字节）的结果。也许这就是问题......记住我使用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();
}
*/
%>
答案 0 :(得分：12)
您的签名字符串包含256个字符，但这是十六进制的，实际上代表128个字节。
在验证签名之前，必须将其转换回字节数组。这不是通过someString.getBytes()实现的，而是通过DatatypeConverter.parseHexBinary(someString)（或您偏爱Google的任何其他方法）实现的。
此外，我强烈建议您在签名邮件时使用Signature类而不是Cipher类。目前，您的代码只能处理长度小于128字节的消息（实际上，由于填充较小）。相反，您应该在签名之前对邮件进行哈希处理（例如，使用SHA256withRSA mechanism）。
答案 1 :(得分：0)
您需要通过publicKey分割数据
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);
}
答案 2 :(得分：0)
正如Duncan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，它返回了172字节数组。
顺便说一下，我有1024位RSA密钥。
答案 3 :(得分：0)
首先将文本转换为十六进制然后加密，加密后可以从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));
}
答案 4 :(得分：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;