OpenSSL: prefer ChaCha20 ciphersuites.

openssl/ssl/ssl_ciph.c

 /* ssl/ssl_ciph.c */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
  * This package is an SSL implementation written
  * by Eric Young (eay@cryptsoft.com).
  * The implementation was written so as to conform with Netscapes SSL.
  * 
  * This library is free for commercial and non-commercial use as long as
  * the following conditions are aheared to.  The following conditions
@@ skipping 1424 matching lines @@
                                    disabled_mkey, disabled_auth, disabled_enc, disabled_mac, disabled_ssl,
                                    co_list, &head, &tail);
 
 
         /* Now arrange all ciphers by preference: */
 
         /* Everything else being equal, prefer ephemeral ECDH over other key exchange mechanisms */
         ssl_cipher_apply_rule(0, SSL_kEECDH, 0, 0, 0, 0, 0, CIPHER_ADD, -1, &head, &tail);
         ssl_cipher_apply_rule(0, SSL_kEECDH, 0, 0, 0, 0, 0, CIPHER_DEL, -1, &head, &tail);
 
-        /* AES is our preferred symmetric cipher */
+        /* CHACHA20 is fast and safe on all hardware and is thus our preferred
+         * symmetric cipher, with AES second. */
+        ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20POLY1305, 0, 0, 0, CIPHER_ADD, -1, &head, &tail);
         ssl_cipher_apply_rule(0, 0, 0, SSL_AES, 0, 0, 0, CIPHER_ADD, -1, &head, &tail);
 
         /* Temporarily enable everything else for sorting */
         ssl_cipher_apply_rule(0, 0, 0, 0, 0, 0, 0, CIPHER_ADD, -1, &head, &tail);
 
         /* Low priority for MD5 */
         ssl_cipher_apply_rule(0, 0, 0, 0, SSL_MD5, 0, 0, CIPHER_ORD, -1, &head, &tail);
 
         /* Move anonymous ciphers to the end.  Usually, these will remain disabled.
          * (For applications that allow them, they aren't too bad, but we prefer
@@ skipping 478 matching lines @@
         }
 
 const char *SSL_COMP_get_name(const COMP_METHOD *comp)
         {
         if (comp)
                 return comp->name;
         return NULL;
         }
 
 #endif