Match.xml

<key>Name</key>
<string>petitgarconadhoc</string>
<key>ProvisionedDevices</key>
<array>
	<string>59f2970b8b5c7a7d00840de38c8505c7bec9806d</string>
	<string>c35302c1c7eb8b3dcf1dbfe8e43670089241579e</string>
	<string>9f29bcad2efdc86a306321d5dea20f2940eb4aab</string>
</array>
<key>TimeToLive</key>
<integer>324</integer>

Regexp.rb

devices_matches = file.read.scan(%r{
  <key>ProvisionedDevices</key>\s*
    <array>\s*
      (?:<string>([a-f\d]{40})</string>\s*)+
    </array>
  }x)