using mod rewrite for cookie auth

[chx1975]

I have many developer subdomains and I thought I could save a lot of basic auth password enterings by using something like:

RewriteEngine On
RewriteCond %{HTTP:Authorization} "^Basic dGVzdDp0ZXN0$"
RewriteRule ^ - [co=test:test:localhost:3600:/] [L]
 
RewriteCond %{HTTP:Authorization} "!^Basic dGVzdDp0ZXN0$"
RewriteCond %{HTTP_COOKIE} !^test=test$
RewriteRule ^ - [R=401,L]
Header always set WWW-Authenticate 'Basic realm="dev"'

Do you think this is safe?