SSL/Apache/Nginx: Enabling Perfect Forward Secrecy

How to Configure Apache for Forward Secrecy

Add the following lines to your configuration:

1. SSLProtocol all -SSLv2 -SSLv3
2. SSLHonorCipherOrder on

3. For SSLCipherSuite, use one of the following configurations:

   • Configure with RC4

     Use this configuration if you have a preference for GCM (Galois Counter Mode) suites (these suites are resistant to timing attacks) and RC4 (RC4 is resistant to BEAST). To improve performance, use the faster ECDHE suites whenever possible.

     SSLCipherSuite “EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS”

   • Configure without RC4

     Use this configuration if you have a preference for GCM (Galois Counter Mode) suites (these suites are resistant to timing attacks) and you prefer not to use RC4. To improve performance, use the faster ECDHE suites whenever possible.

     SSLCipherSuite “EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS !RC4”

   • Configure with RC4 as a last resort to support wide range and older browsers

     Use this configuration if you have a preference for GCM (Galois Counter Mode) suites (these suites are resistant to timing attacks) and you want to use RC4 only as a last resort in order to support a wide range of browsers and/or older browsers. To improve performance, use the faster ECDHE suites whenever possible.

     SSLCipherSuite “EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS +RC4 RC4”

How to Configure Nginx for Forward Secrecy

To configure Nginx for Forward Secrecy, you configure the server to actively choose cipher suites and then activate the right OpenSSL cipher suite configuration string.

Add the following lines to your configuration:

1. ssl_protocols TLSv1.2 TLSv1.1 TLSv1;

2. ssl_prefer_server_ciphers on;

3. For ssl_ciphers, use one of the following configurations:

   • Configure with RC4

     Use this configuration if you have a preference for GCM (Galois Counter Mode) suites (these suites are resistant to timing attacks) and RC4 (RC4 is resistant to BEAST). To improve performance, use the faster ECDHE suites whenever possible.

     ssl_ciphers “EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS”;

   • Configure without RC4

     Use this configuration if you have a preference for GCM (Galois Counter Mode) suites (these suites are resistant to timing attacks) and you prefer not to use RC4. To improve performance, use the faster ECDHE suites whenever possible.

     ssl_ciphers “EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS !RC4”;

   • Configure with RC4 as a last resort to support wide range and older browsers

     Use this configuration if you have a preference for GCM (Galois Counter Mode) suites (these suites are resistant to timing attacks) and you want to use RC4 only as a last resort in order to support a wide range of browsers and/or older browsers. To improve performance, use the faster ECDHE suites whenever possible.

     ssl_ciphers “EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS +RC4 RC4”;

https://www.digicert.com/ssl-support/ssl-enabling-perfect-forward-secrecy.htm