[CentOS] base64 response for websockets

I'm trying to generate the correct response to a websocket connect.

The websocket connect is:
GET /chat HTTP/1.1
Host: example.com:8000
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Sec-WebSocket-Version: 13

So I take the Sec-WebSocket-Key above and add the extra part and put that
in /tmp/sha1
dGhlIHNhbXBsZSBub25jZQ==258EAFA5-E914-47DA-95CA-C5AB0DC85B11

I then run sha1sum /tmp/sha1 and it gives:
05082898ab78f6da9c1ad2587b8012cd0cf52172

I put that in a file /tmp/base64 and run
base64 /tmp/base64

The result of that is:
MDUwODI4OThhYjc4ZjZkYTljMWFkMjU4N2I4MDEyY2QwY2Y1MjE3Mgo=

Which is not correct. Its supposed to be s3pPLMBiTxaQ9kYGzzhZRbK+xOo=

What am I not doing correct?

Thanks,

Jerry