What is the difference between Web Express Logon, Certificate Express Logon and Reuse Active Credentials?

Z and I Emulator for Web offers three types of Express Logon:

Reuse Active Credentials provides automated authentication on all emulation platforms. It is not as comprehensive as Web Express Logon but does not require any special network configuration. If a new connection is made to a host and a user has already authenticated to that host somehow, those credentials are applied to the new connection. The credentials are maintained for as long as Z and I Emulator for Web is running in the JVM. The credentials are only stored in Java memory and once the JVM closes they will have to be re-entered when Z and I Emulator for Web is restarted.

Although all three types of Express Logon allow users to log on to a host system without having to enter a user ID and password, they have different requirements for session type, client certificates, and SSL configuration. Certificate Express Logon works exclusively with 3270 session types and requires client-side certificates and an SSL connection to a TN3270 server. Web Express Logon and Reuse Active Credentials offer a wide variety of styles that function with all Z and I Emulator for Web session types (not just 3270 emulation). Certificate Express Logon requires a macro to log on to the host application and then distribute that macro to the clients. Web Express Logon and Reuse Active Credentials may or may not require a macro, depending on your environment.