Today's episode is brought to you by the letters S and D.

Secret Diary. Not of Adrian Mole.

Today's update introduces a new privacy setting for entries and diaries. Secret.

Secret diaries and entries are cryptographically encoded in such a way that no-one except the person with the unlock passphrase can ever hope to read them. The data is encrypted in the user's browser and then sent to us. We do not store the key that's created from your passphrase and as a result neither us, any hackers nor governments can read your entries.

This comes at a trade off though. If you lose the passphrase (and the recovery phrase) we can not recover your entries. At all. Similarly, you cannot search within them because the search engine within DD needs to be able to read your entries in order to know what it contains. In the case of secret entries that's not possible. At the moment you cannot export secret entries either because the export process is done on the server then sent to you. This too would not work.

The passphrase is set when you create your first secret entry or diary and should be set to something only you can remember and be completely different to your account password if you have one.

Supplying your secret passphrase is required to view secret entries and will be remembered for 30 minutes by default. You can adjust this under Account Settings -> Secret Diary / Secret Entries. You can change your passphrase here too if you decide to. If your secrets are unlocked you will not need to enter your current passphrase to change to a new one, but if your secrets are locked then you will need to enter the secret passphrase.

If you have a secret diary and any other type of diary, then switching from secret to another diary will automatically lock your secret diary. You can lock your secret diary manually by hitting the lock icon.

Locked secret diaries will not display any entries in the sidebar (to avoid information leak) - unlocking the diary will update the sidebar to show the entries. (The entry list drawer on mobile).

The encryption system uses industry standard techniques, NIST-standardised, FIPS 140-2 approved algorithms built in to your browser provided you're using a standard browser that's been released after about 2017. Which you should be because other aspects of DD will require it anyway.

Secret Diaries and Entries are a Plus only feature. Any Plus enabled diary can have secret entries. A Plus enabled user can create a Secret Diary. A Secret Diary must be created from new - an existing Diary cannot be converted to a secret diary (this would be pointless) and a Secret Diary cannot be reverted to a private, followers or public diary. Once secret diary, always a secret diary.

Secret entries within a private, followers or public diary can be made private, followers only or public and can be switched between any of those states.

Secret diaries are never shown on any of the public facing site at all. And even if a software bug does for some reason show a secret diary, its contents will appear as garbled strings of encrypted text because only the diary owner, with the correct secret passphrase can perform the unencryption.

Of course, I can't provide a demo of this - but for the Plus users among you, by all means have a play!

Any issues, as always please give me a yell.