Messages like "your connection is encrypted with 256-bit encryption" don't tell you anything about the size of the RSA keys in use. During the TLS handshake, y

Messages like "your connection is encrypted with 256-bit encryption" don't tell you anything about the size of the RSA keys in use. During the TLS handshake, your browser and the server do public-key crypto to authenticate each other and share private information without a previously-known shared secret. Because public-key crypto is really, really slow, they then share a small secret (say, 128 or 256 bits), and use that secret as the key for a traditional symmetric encryption algorithm like AES. That's the number you're seeing. Take a look at https://en.wikipedia.org/wiki/Transport_Layer_Security https://en.wikipedia.org/wiki/Transport_Layer_Security