Java and HTTPS url connection without downloading certificate

Question

This code connects to a HTTPS site and I am assuming I am not verifying the certificate   But  why don t I have to install a certificate locally for the site   Shouldn t I have to install a certificate locally and load it for this program or is it downloaded behind the covers   Is the traffic between the client to the remote site still encrypted in transmission   import java io BufferedReader  import java io InputStreamReader  import java io Reader  import java net URL  import java net URLConnection  import java security cert X509Certificate   import javax net ssl HostnameVerifier  import javax net ssl HttpsURLConnection  import javax net ssl SSLContext  import javax net ssl SSLSession  import javax net ssl TrustManager  import javax net ssl X509TrustManager   public class TestSSL        public static void main String   args  throws Exception              Create a trust manager that does not validate certificate chains         TrustManager   trustAllCerts   new TrustManager     new X509TrustManager                 public java security cert X509Certificate   getAcceptedIssuers                     return null                            public void checkClientTrusted X509Certificate   certs  String authType                              public void checkServerTrusted X509Certificate   certs  String authType                                          Install the all-trusting trust manager         final SSLContext sc   SSLContext getInstance  SSL            sc init null  trustAllCerts  new java security SecureRandom             HttpsURLConnection setDefaultSSLSocketFactory sc getSocketFactory                Create all-trusting host name verifier         HostnameVerifier allHostsValid   new HostnameVerifier                 public boolean verify String hostname  SSLSession session                    return true                                       Install the all-trusting host verifier         HttpsURLConnection setDefaultHostnameVerifier allHostsValid            URL url   new URL  https   www google com            URLConnection con   url openConnection            final Reader reader   new InputStreamReader con getInputStream             final BufferedReader br   new BufferedReader reader                   String line               while   line   br readLine       null                System out println line                             br close             End of main       End of the class

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Use the latest X509ExtendedTrustManager instead of X509Certificate as advised here  java security cert CertificateException  Certificates does not conform to algorithm constraints      package javaapplication8       import java io InputStream      import java net Socket      import java net URL      import java net URLConnection      import java security cert CertificateException      import java security cert X509Certificate      import javax net ssl HostnameVerifier      import javax net ssl HttpsURLConnection      import javax net ssl SSLContext      import javax net ssl SSLEngine      import javax net ssl SSLSession      import javax net ssl TrustManager      import javax net ssl X509ExtendedTrustManager                          author hoshantm             public class JavaApplication8                            param args the command line arguments             throws java lang Exception                     public static void main String   args  throws Exception                                  fix for                   Exception in thread  main  javax net ssl SSLHandshakeException                       sun security validator ValidatorException                           PKIX path building failed  sun security provider certpath SunCertPathBuilderException                               unable to find valid certification path to requested target                             TrustManager   trustAllCerts   new TrustManager                    new X509ExtendedTrustManager                          Override                     public java security cert X509Certificate   getAcceptedIssuers                             return null                                              Override                     public void checkClientTrusted X509Certificate   certs  String authType                                                Override                     public void checkServerTrusted X509Certificate   certs  String authType                                                Override                     public void checkClientTrusted X509Certificate   xcs  String string  Socket socket  throws CertificateException                                                Override                     public void checkServerTrusted X509Certificate   xcs  String string  Socket socket  throws CertificateException                                                Override                     public void checkClientTrusted X509Certificate   xcs  String string  SSLEngine ssle  throws CertificateException                                                Override                     public void checkServerTrusted X509Certificate   xcs  String string  SSLEngine ssle  throws CertificateException                                                                         SSLContext sc   SSLContext getInstance  SSL                sc init null  trustAllCerts  new java security SecureRandom                 HttpsURLConnection setDefaultSSLSocketFactory sc getSocketFactory                     Create all-trusting host name verifier             HostnameVerifier allHostsValid   new HostnameVerifier                      Override                 public boolean verify String hostname  SSLSession session                        return true                                                  Install the all-trusting host verifier             HttpsURLConnection setDefaultHostnameVerifier allHostsValid                                 end of the fix                              URL url   new URL  https   10 52 182 224 cgi-bin dynamic config panel bmp                URLConnection con   url openConnection                  Reader reader   new ImageStreamReader con getInputStream                  InputStream is   new URL url toString    openStream                    Whatever you may want to do next

User · Answer

A simple  but not pure java solution  is to shell out to curl from java  which gives you complete control over how the request is done  If you re just doing this for something simple  this allows you to ignore certificate errors at times  by using this method  This example shows how to make a request against a secure server with a valid or invalid certificate  pass in a cookie  and get the output using curl from java   import java io BufferedReader  import java io File  import java io IOException  import java io InputStreamReader   public class MyTestClass     public static void main String   args           String url    https   www google com       String sessionId    faf419e0-45a5-47b3-96d1-8c62b2a3b558           Curl options are         -k  ignore certificate errors        -L  follow redirects        -s  non verbose        -H  add a http header      String   command      curl    -k    -L    -s    -H    Cookie  MYSESSIONCOOKIENAME     sessionId         -H    Accept       url        String output   executeShellCmd command    tmp   true  true       System out println output          public String executeShellCmd String   command  String workingFolder  boolean wantsOutput  boolean wantsErrors          try             ProcessBuilder pb   new ProcessBuilder command         File wf   new File workingFolder         pb directory wf          Process proc   pb start          BufferedReader stdInput   new BufferedReader new InputStreamReader proc getInputStream            BufferedReader stdError   new BufferedReader new InputStreamReader proc getErrorStream             StringBuffer sb   new StringBuffer          String newLine   System getProperty  line separator          String s            read stdout from the command       if  wantsOutput                  while   s   stdInput readLine       null                      sb append s             sb append newLine                               read any errors from the attempted command       if  wantsErrors                  while   s   stdError readLine       null                      sb append s             sb append newLine                            String result   sb toString           return result            catch  IOException e              throw new RuntimeException  Problem occurred    e

User · Answer

But why don t I have to install a certificate locally for the site    Well the code that you are using is explicitly designed to accept the certificate without doing any checks whatsoever   This is not good practice     but if that is what you want to do  then  obviously  there is no need to install a certificate that your code is explicitly ignoring      Shouldn t I have to install a certificate locally and load it for this program or is it downloaded behind the covers     No  and no   See above      Is the traffic between the client to the remote site still encrypted in transmission    Yes it is   However  the problem is that since you have told it to trust the server s certificate without doing any checks  you don t know if you are talking to the real server  or to some other site that is pretending to be the real server   Whether this is a problem depends on the circumstances        If we used the browser as an example  typically a browser doesn t ask the user to explicitly install a certificate for each ssl site visited     The browser has a set of trusted root certificates pre-installed   Most times  when you visit an  https  site  the browser can verify that the site s certificate is  ultimately  via the certificate chain  secured by one of those trusted certs   If the browser doesn t recognize the cert at the start of the chain as being a trusted cert  or if the certificates are out of date or otherwise invalid   inappropriate   then it will display a warning   Java works the same way   The JVM s keystore has a set of trusted certificates  and the same process is used to check the certificate is secured by a trusted certificate      Does the java https client api support some type of mechanism to download certificate information automatically    No   Allowing applications to download certificates from random places  and install them  as trusted  in the system keystore would be a security hole

User · Answer

Java and HTTPS url connection without downloading certificate   If you really want to avoid downloading the server s certificate  then use an anonymous protocol like Anonymous Diffie-Hellman  ADH   The server s certificate is not sent with ADH and friends   You select an anonymous protocol with setEnabledCipherSuites  You can see the list of cipher suites available with getEnabledCipherSuites   Related  that s why you have to call SSL get peer certificate in OpenSSL  You ll get a X509 V OK with an anonymous protocol  and that s how you check to see if a certificate was used in the exchange   But as Bruno and Stephed C stated  its a bad idea to avoid the checks or use an anonymous protocol     Another option is to use TLS-PSK or TLS-SRP  They don t require server certificates either   But I don t think you can use them    The rub is  you need to be pre-provisioned in the system because TLS-PSK is Pres-shared Secret and TLS-SRP is Secure Remote Password  The authentication is mutual rather than server only   In this case  the mutual authentication is provided by a property that both parties know the shared secret and arrive at the same premaster secret  or one  or both  does not and channel setup fails  Each party proves knowledge of the secret is the  mutual  part   Finally  TLS-PSK or TLS-SRP don t do dumb things  like cough up the user s password like in a web app using HTTP  or over HTTPS   That s why I said each party proves knowledge of the secret

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The reason why you don t have to load a certificate locally is that you ve explicitly chosen not to verify the certificate  with this trust manager that trusts all certificates   The traffic will still be encrypted  but you re opening the connection to Man-In-The-Middle attacks  you re communicating secretly with someone  you re just not sure whether it s the server you expect  or a possible attacker   If your server certificate comes from a well-known CA  part of the default bundle of CA certificates bundled with the JRE  usually cacerts file  see JSSE Reference guide   you can just use the default trust manager  you don t have to set anything here   If you have a specific certificate  self-signed or from your own CA   you can use the default trust manager or perhaps one initialised with a specific truststore  but you ll have to import the certificate explicitly in your trust store  after independent verification   as described in this answer  You may also be interested in this answer

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If you are using any Payment Gateway to hit any url just to send a message  then i used a webview by following it    How can load https url without use of ssl in android webview  and make a webview in your activity with visibility gone  What you need to do   just load that webview   like this     webViewForSms setWebViewClient new SSLTolerentWebViewClient                     webViewForSms loadUrl   https   bulksms com                               username test amp password test 123 amp messageType text amp mobile                            mobileEditText getText   toString     amp senderId ATZEHC amp message Your 20OTP 20for 20A2Z 20registration 20is 20124      Easy   You will get this  SSLTolerentWebViewClient from this link  How can load https url without use of ssl in android webview

[java] Java and HTTPS url connection without downloading certificate

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