我正在 Java 中实现一个 WebService，其中服务器需要使用 RSA 算法向客户端发送 3DES key 。对称由服务器生成。服务器和客户端都有自己的 RSA key 对，这些 key 对之前已交换。
在此代码中，服务器将对称 key 发送给客户端。
@WebMethod
public byte[] getSymmetricKey(){
try{
Cipher cipher = Cipher.getInstance("RSA");
// First, encrypts the symmetric key with the client's public key
cipher.init(Cipher.ENCRYPT_MODE, this.clientKey);
byte[] partialCipher = cipher.doFinal(this.key.getBytes());
// Finally, encrypts the previous result with the server's private key
cipher.init(Cipher.ENCRYPT_MODE, this.privateKey);
byte[] cipherData = cipher.doFinal(partialCipher);
return cipherData;
}catch (Exception ex){
ex.printStackTrace();
}
}
当我使用服务器的私钥运行加密时，出现 IllegalBlockSizeException 错误。如果默认激活填充，为什么会出现此异常？我还尝试使用 Cipher.getInstance("RSA/ECB/PKCS1Padding") 显式激活填充。
最后，这是异常输出:
SEVERE: javax.crypto.IllegalBlockSizeException: Data must not be longer than 245 bytes
javax.crypto.IllegalBlockSizeException: Data must not be longer than 245 bytes
at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:346)
at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:391)
at javax.crypto.Cipher.doFinal(Cipher.java:2087)
at server.FileTransfererImpl.getSymmetricKey(FileTransfererImpl.java:112)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.Trampoline.invoke(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.MethodUtil.invoke(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.xml.internal.ws.api.server.MethodUtil.invoke(Unknown Source)
at com.sun.xml.internal.ws.api.server.InstanceResolver$1.invoke(Unknown Source)
at com.sun.xml.internal.ws.server.InvokerTube$2.invoke(Unknown Source)
at com.sun.xml.internal.ws.server.sei.EndpointMethodHandler.invoke(Unknown Source)
at com.sun.xml.internal.ws.server.sei.SEIInvokerTube.processRequest(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber.__doRun(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber._doRun(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber.doRun(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber.runSync(Unknown Source)
at com.sun.xml.internal.ws.server.WSEndpointImpl$2.process(Unknown Source)
at com.sun.xml.internal.ws.transport.http.HttpAdapter$HttpToolkit.handle(Unknown Source)
at com.sun.xml.internal.ws.transport.http.HttpAdapter.handle(Unknown Source)
at com.sun.xml.internal.ws.transport.http.server.WSHttpHandler.handleExchange(Unknown Source)
at com.sun.xml.internal.ws.transport.http.server.WSHttpHandler.handle(Unknown Source)
at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source)
at sun.net.httpserver.AuthFilter.doFilter(Unknown Source)
at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source)
at sun.net.httpserver.ServerImpl$Exchange$LinkHandler.handle(Unknown Source)
at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source)
at sun.net.httpserver.ServerImpl$Exchange.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
最佳答案
我今天正在研究一些东西，发现了这个问题。由于尚未得到答复，我将其留在这里以供将来引用。
根据 PKCS #1，RSAES-PKCS1-V1_5-ENCRYPT算法最多可以加密k - 11字节，其中 k是 key 的“大小”(以字节为单位)。这 11 个字节用于“ header ”。
如果您使用 2048 位 RSA key ，则为 k = 256您最多可以加密 256 - 11 = 245数据字节。
检查this.key的实际大小.
关于java - Java 中 3DES 与 RSA 的 key 交换，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27322235/