Is Profile Properties safe to keep user information ?

Hi ,
I want to use Profile Properties to keep some user information and move them between pages.
I'm wondering if those profile properties are keeping data session based or when I assigned them
is it same for all sessions ?
Is this a safe method to use them:
<anonymousIdentification enabled="true"/>
<profile enabled="true">
      <properties>
        <add name="userid" defaultValue="" />
        <add name="password" defaultValue="" />
        <add name="username" defaultValue="" />
      </properties>
    </profile>
...