Discussion: Encryption with Libsodium

The original Design Document is at HLD Removing mcrypt and adding libsodium.

Purpose of this page is to provide transparency via an open discussion. The page may include:

• open questions
• ideas and proposals
• notes and action items from the meetings

The page will be updated as the discussion progresses. See revisions of the page if needed.

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Tasks

See epic https://app.zenhub.com/workspace/o/magento-engcom/php-7.2-support/issues/127

To Investigate

1. Decide on migration strategy (#134)
   1. Calculate possible amount of stored encrypted data
2. Investigate if it's safe to use https://github.com/paragonie/sodium_compat (#133)
   1. It supports functions mentioned above
3. Based on the #2 decide on the implementation strategy:
   1. Completely switch to sodium (if sodium_compat is an acceptable option)
   2. Support both mcrypt and sodium based on what's installed in the system. Use mcrypt_compat for mcrypt support as we don't have mcrypt in composer.json requirements

Update or Add to the HLD

1. Use crypto_aead_*: What functions should we use: crypto_aead_* or crypto_secretbox*? See - recommendations (includes code sample)
   1. Also, clarify what ciphers are used to understand what needs to be added to the ciphertext
      1. XChaCha20-Poly1305-IETF (check what's supported by current library version) for crypto_aead_xchacha20poly1305_ietf or xsalsa20poly1305 for crypto_secretbox
2. Use mcrypt for decrypting existing data. Use mcrypt_compat. The \Magento\Framework\Encryption\Crypt::encrypt() in Magento Framework should be deprecated

May 4th Call

• First step: encryption only. Hashing can be done as a separate step later.
  • To confirm with Piotr (Olga)
• Use crypto_aead_xchacha20poly1305_ietf*
  • Update HLD (Olga)
• Data migration:
  1. Support "on-demand" approach. Current pattern in decryption supports this, we should follow it.
  2. Migrate on upgrade step. Investigate upgrade performance implications. Run test on different amount of data.
     • Create a task (Olga)
• https://github.com/paragonie/sodium_compat
  • Follow-up on whether we can use this (Steven)
  1. Use sodium_compat for development now. Change later if necessary
• https://github.com/phpseclib/mcrypt_compat
  • Follow-up on whether we can use this (Steven)
• Check performance with new implementation, both with native Sodium and sodium_compat one.
  • Create a task (Olga)