The security controls for your database are:

Access Control by Source IP/Subnet

The number of source IP rules that you can add depends on the Redis Cloud Essentials plan that you purchased. For example, the 1GB plan allows up to 8 source IP authentication rules. These rules can contain either IP or CIDR notation.

Source
IP/Subnet

If you need more source IP rules than your current REC plan includes, consider changing to a plan with more source IP rules.

You may change your subscription at any time by going to Databases => Configuration => Edit => Access Control & Security.

Note: only the account owner can upgrade/downgrade the subscription.

Securing Connection to Your Database with SSL/TLS

There is a dedicated page on this topic with steps you need to achieve this.

Redis Password

You can and should add a password for your database. This password is purely for full access to the data in the database.

One feature often overlooked is the little eye icon on the right side of form field that can be used to view the password.

redis
password

AWS Security groups

This option accepts the Group Name and the AWS Account ID as input to identify the security group and secure your database.

Note: This feature is only for use when your database subscription is in Amazon Web Services and only for the rare times people run using EC2 classic as AWS recommends people use VPCs most times these days.