Hiawatha is using PolarSSL for SSL/TLS implemention known commonly as https, which is forced to be used here by setting: RequireSSL = yes inside the VirtualHost section. I think it activates Strict Transport Security (HSTS) with max-age of 31536000 aswell. Another really cool feature by Hiawatha is the RandomHeader = 1000 option, which has to be put into the VirtualHost section. In the above case, it adds between 1 and 1000 Bytes of Header Response. This helps prevent attackers from guessing what file was requested based on the response length. Hiawatha is the first webserver I know of, that implements such genious technique. HTTPS Header when RandomHeader activated: curl -I HTTP/1.1 200 OKDate: Sun, 29 Jun 2014 07:20:11 GMTServer: Hiawatha v9.6Connection: keep-aliveX-Random: iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiStrict-Transport-Security: max-age=31536000Transfer-Encoding: chunked as you see it adds X-Random, it is indeed random, here are some other X-Random headers X-Random: 77777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777777X-Random: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFX-Random: 999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999X-Random: PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPX-Random: 444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444X-Random: BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBX-Random: jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj So every https transfer size differs, even if the page is the same. I like it a lot. The webserver also uses TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA(with Forward Secrecy of course) by default! 1024Bit is the default Diffie-Hellman Keysize, it can be increased up to 4096 by setting DHsize = 4096 into the servers main configuration. Lets compare the ciphers of PolarSSL to the more often used SSL Library, OpenSSL 1.0.1h Ciphers AES, Blowfish, Camellia, SEED, CAST-128, DES, IDEA, RC2, RC4, RC5, Triple DES, GOST 28147-89[7]Cryptographic hash functions MD5, MD4, MD2, SHA-1, SHA-2, RIPEMD-160, MDC-2, GOST R 34.11-94[7]Public-key cryptography RSA, DSA, Diffie–Hellman key exchange, Elliptic curve, GOST R 34.10-2001[7](Perfect forward secrecy is supported using elliptic curve Diffie–Hellman since version 1.0.[8]) PolarSSL 1.3.7 Ciphers AES, Camellia, DES, RC4, RC5, Triple DES, XTEA, BlowfishCryptographic hash functions MD5, MD2, MD4, SHA-1, SHA-2Public-key cryptography RSA, Diffie-Hellman key exchange, Elliptic curve cryptography (ECC), Elliptic curve Diffie–Hellman (ECDH), Elliptic Curve DSA (ECDSA) PolarSSL is neat having a smaller footprint, especially in combination with Hiawatha, which adds some security to https aswell. Set MinSSLversion = TLS1.2 if you want to support only the latest TLS version for maxed out security, older computers can’t visit your https page anymore though. From my Hiawatha article series