I'm not sure you are understanding this. Both sides derive the same master key, so there is no need to send it. After the handshake the SSL code will use that key to generate specific encryption keys and perform encryption of further traffic through the tunnel. If you are only using the handshake to generate the master key to be used elsewhere (e.g. for proprietary encryption), then you can get it from the SSL_SESSION object (not sure if there's a get method).
.................................... Erik Tkal Juniper OAC/UAC/Pulse Development From: owner-openssl-us...@openssl.org [mailto:owner-openssl-us...@openssl.org] On Behalf Of krishnamurthy santhanam Sent: Wednesday, August 24, 2011 12:51 AM To: openssl-users@openssl.org Subject: Re: creating Master-Key for encryption/decryption Thanks. As per my understanding,Before sending master key to client , server has to maintain the master key. How i can get this in server side? is there any code sample or snippet to get this key? Krishna On Tue, Aug 23, 2011 at 11:54 PM, Gayathri Sundar <suraj...@gmail.com<mailto:suraj...@gmail.com>> wrote: Master key is unique per session, and its same for both client and server, thats the concept behind the SSL handshake. The RFC would state the information accurately. Perhaps you can send the master secret as part of ur application data, to the client, which can decrypt and use. Thanks --Gayathri On Tue, Aug 23, 2011 at 12:41 PM, krishnamurthy santhanam <krishnamurth...@gmail.com<mailto:krishnamurth...@gmail.com>> wrote: Thanks. I gone through the RFC 2246 and understood the Master key generation part. The Master key is generated and able to print the client side(test C program) using ssl strucure. printf("session A\n"); SSL_SESSION *session = SSL_get_session(ssl); SSL_SESSION_print(out, session); for (i=0; i<(unsigned int)session->master_key_length; i++) { BIO_printf(bp,"%02X",session->master_key[i]) ); } How i can get the same Master key in server side? in my scenario, server side program is running in C. JDBC clients will establish the connection to the server. will the same Mester key generated in the cross platforms(JDBC client side)? Any help will be great. Thanks for your time, Krishnamurthy On Mon, Aug 22, 2011 at 9:03 PM, Gayathri Sundar <suraj...@gmail.com<mailto:suraj...@gmail.com>> wrote: Please read the RFC, it would clearly explain how the master secret is dervied, and from that how the read and write keys are derived. With that you can get to know how to extract the read n write keys. Meanwhile the read and wirte keys are available as part of the ssl object. Check that structure out. Thanks --Gayathri On Mon, Aug 22, 2011 at 10:24 AM, krishnamurthy santhanam <krishnamurth...@gmail.com<mailto:krishnamurth...@gmail.com>> wrote: I have more than 100 clients that will connect to my server and communicate the data. I am implementing SSL on server side to authenticate the client certificate(X.509) and also client will authenticate the servers certificate. Once the mutual authentication has completed I have to generate master key for encryption and decryption. I am going to use AES for encryption and decryption. I had generated the client and server certificates using the bellow commands and signed by the root, 1. CLIENT CERTIFICATE: openssl req -newkey rsa:1024 -sha1 -keyout clientkey.pem -out clientreq.pem openssl x509 -req -in clientreq.pem -sha1 -extfile openssl.cnf -extensions usr_cert -CA rootcert.pem -CAkey rootkey.pem -CAcreateserial -out clientcert.pem cat clientkey.pem clientcert.pem rootcert.pem > client.pem openssl x509 -subject -issuer -noout -in client.pem 2. SERVER CERTIFICATE: openssl req -newkey rsa:1024 -sha1 -keyout serverkey.pem -out serverreq.pem openssl x509 -req -in serverreq.pem -sha1 -extfile openssl.cnf -extensions usr_ cert -CA rootcert.pem -CAkey rootkey.pem -CAcreateserial -out servercert.pem cat serverkey.pem servercert.pem rootcert.pem > server.pem openssl x509 -subject -issuer -noout -in server.pem 3. ROOT CERTIFICATE: openssl req -newkey rsa:1024 -sha1 -keyout rootkey.pem -out rootreq.pem openssl x509 -req -in rootreq.pem -sha1 -extfile root.cnf -extensions v3_ca -sig nkey rootkey.pem -out rootcert.pem cat rootcert.pem rootkey.pem > root.pem openssl x509 -subject -issuer -noout -in root.pem Initially I am writing ssl/tls programming for server and client. In this I am able to communicate the data between client and server. I was struck on master key generation, I have added the below LOC to programs to get MASTER KEY, printf("session A\n"); SSL_SESSION *session = SSL_get_session(ssl); SSL_SESSION_print(out, session); It is printing like this , session A SSL-Session: Protocol : TLSv1 Cipher : AES256-SHA Session-ID: 9FCE46513DD74882D3FF0E0E84CC4A6BE12192B65C426E0B27D0FA15F81D7D5E Session-ID-ctx: Master-Key: 56F90B0D90DEB3430207A74793C9B6565744E06ECA191D9DFA04C29B1EE2B782 6B602878597465F739AD69091DDF6499 Key-Arg : None Krb5 Principal: None Compression: 1 (zlib compression) Start Time: 1314015355 Timeout : 7200 (sec) Is this the Master key for both the server and client? Is this the key that should be used for the encryption in client side and decryption in server side? If this is the Master key how can I extract the key? Please guide me if I understood anything wrong.
