diff -pur ../cyrus-imapd-2.4.17/doc/man/imapd.conf.5.html ./doc/man/imapd.conf.5.html
--- ../cyrus-imapd-2.4.17/doc/man/imapd.conf.5.html	2012-12-01 20:59:55.000000000 +0100
+++ ./doc/man/imapd.conf.5.html	2014-10-16 02:29:41.366857590 +0200
@@ -2150,6 +2150,12 @@ that a TLS session will be cached for la
 maximum value is 1440 (24 hours), the default. A value of 0
 will disable session caching.</p>
 
+<p style="margin-left:11%;"><b>tls_ec:</b>
+prime256v1</p>
+
+<p style="margin-left:18%;">This configures which elliptical
+curve parameter to use for TLS.</p>
+
 <p style="margin-left:11%;"><b>umask:</b> 077</p>
 
 <p style="margin-left:18%;">The umask value used by various
diff -pur ../cyrus-imapd-2.4.17/imap/tls.c ./imap/tls.c
--- ../cyrus-imapd-2.4.17/imap/tls.c	2012-12-01 20:57:54.000000000 +0100
+++ ./imap/tls.c	2014-10-16 02:31:46.446883444 +0200
@@ -630,6 +630,7 @@ int     tls_init_serverengine(const char
     const char   *CAfile;
     const char   *s_cert_file;
     const char   *s_key_file;
+    const char   *ec;
     int    requirecert;
     int    timeout;
 
@@ -747,6 +748,28 @@ int     tls_init_serverengine(const char
     /* FIXME: Load ECDH params for ECDHE suites when 0.9.9 is released */
 #endif
 
+#if (OPENSSL_VERSION_NUMBER >= 0x1000103fL)
+
+    /* Setup an ec - default to X9.62/SECG curve over a 256 bit prime field */
+
+    ec = config_getstring(IMAPOPT_TLS_EC);
+
+    int openssl_nid = OBJ_sn2nid(ec);
+    if (openssl_nid != 0) {
+      EC_KEY *ecdh;
+      ecdh = EC_KEY_new_by_curve_name(openssl_nid);
+      if (ecdh != NULL) {
+        SSL_CTX_set_tmp_ecdh(s_ctx, ecdh);
+        EC_KEY_free(ecdh);
+        } else {
+            syslog(LOG_NOTICE,"TLS server engine: unknown tls_ec specified");	
+        }
+    } else {
+	    syslog(LOG_NOTICE,"TLS server engine: unknown tls_ec specified");	
+    }
+
+#endif
+
     verify_depth = verifydepth;
     if (askcert!=0)
 	verify_flags |= SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE;
diff -pur ../cyrus-imapd-2.4.17/lib/imapoptions ./lib/imapoptions
--- ../cyrus-imapd-2.4.17/lib/imapoptions	2014-10-16 02:28:24.662859234 +0200
+++ ./lib/imapoptions	2014-10-16 02:29:41.374856717 +0200
@@ -1408,6 +1408,10 @@ product version in the capabilities */
    for later reuse.  The maximum value is 1440 (24 hours), the
    default.  A value of 0 will disable session caching. */
 
+{ "tls_ec", "prime256v1", STRING }
+/* The default elliptical curve parameter.
+   For list of curves see: openssl ecparam -list_curves */
+
 { "umask", "077", STRING }
 /* The umask value used by various Cyrus IMAP programs. */