1 files changed, 28 insertions, 0 deletions
diff --git a/lib/gitlab/utils/email.rb b/lib/gitlab/utils/email.rb
new file mode 100644
index 00000000000..c65d7165263
--- /dev/null
+++ b/lib/gitlab/utils/email.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Utils
+    module Email
+      extend self
+
+      # Replaces most visible characters with * to obfuscate an email address
+      # deform adds a fix number of * to ensure the address cannot be guessed. Also obfuscates TLD with **
+      def obfuscated_email(email, deform: false)
+        regex = ::Gitlab::UntrustedRegexp.new('^(..?)(.*)(@.?)(.*)(\..+)$')
+        match = regex.match(email)
+        return email unless match
+
+        if deform
+          # Ensure we can show two characters for the username, even if the username has
+          # only one character. Boring solution is to just duplicate the character.
+          email_start = match[1]
+          email_start += email_start if email_start.length == 1
+
+          email_start + '*' * 5 + match[3] + '*' * 5 + "#{match[5][0..1]}**"
+        else
+          match[1] + '*' * (match[2] || '').length + match[3] + '*' * (match[4] || '').length + match[5]
+        end
+      end
+    end
+  end
+end