IP Anonymizer

🌎 IP address anonymizer for Ruby and Rails

Works with IPv4 and IPv6

Designed to help with GDPR compliance

Getting Started

Add these lines to your application’s Gemfile:

gem "ip_anonymizer"

There are two strategies for anonymizing IPs.

Masking

This is the approach Google Analytics uses for IP anonymization:

• For IPv4, set the last octet to 0
• For IPv6, set the last 80 bits to zeros

IpAnonymizer.mask_ip("8.8.4.4")
# => "8.8.4.0"

IpAnonymizer.mask_ip("2001:4860:4860:0:0:0:0:8844")
# => "2001:4860:4860::"

An advantange of this approach is geocoding will still work, only with slightly less accuracy. A potential disadvantage is different IPs will have the same mask (8.8.4.4 and 8.8.4.5 both become 8.8.4.0).

Hashing

Transform IP addresses with a keyed hash function (PBKDF2-HMAC-SHA256).

IpAnonymizer.hash_ip("8.8.4.4", key: "secret")
# => "6.128.151.207"

IpAnonymizer.hash_ip("2001:4860:4860:0:0:0:0:8844", key: "secret")
# => "f6e4:a4fe:32dc:2f39:3e47:84cc:e85e:865c"

An advantage of this approach is different IPs will have different hashes (with the exception of collisions).

Make sure the key is kept secret and at least 30 random characters. Otherwise, a rainbow table can be constructed. You can generate a good key with:

SecureRandom.hex(32)

Rails

Automatically anonymize request.remote_ip in Rails.

For masking, add to config/application.rb:

config.middleware.insert_after ActionDispatch::RemoteIp, IpAnonymizer::MaskIp

For hashing, use:

config.middleware.insert_after ActionDispatch::RemoteIp, IpAnonymizer::HashIp, key: "secret"

Related Projects

• Logstop - Keep personally identifiable information (PII) out of your logs

History

View the changelog

Contributing

Everyone is encouraged to help improve this project. Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

To get started with development:

git clone https://github.com/ankane/ip_anonymizer.git
cd ip_anonymizer
bundle install
bundle exec rake test