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Functionality
The P-SMS app is needed to send an encrypted SMS in case the internet is disconnected or unavailable. This will allow peaceful protesters to communicate without the possibility of authoritarian regimes spying on them.
The app allows the message to be encrypted with an encryption key. The recipient of the message must obtain the key to decrypt the SMS in advance.
The global encryption key can be setup in two ways:
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When the application is starts. If the global key is not set, a window will open where the application can generate the key, or you can enter the key you have been given. Then tap the "Save" button.
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In the application settings. You can create/change the encryption key in the application settings by selecting the "Global encryption key" item from the "Partisan settings" section. Generate a new key, or you can enter the key you have been sent. Then tapthe "Save" button.
To delete the global encryption key, select "Global encryption key" in the application settings from the "Partisan settings" section. In the window that opens, save the empty line in the "Encryption key" field by tapping the "Save" button.
Note
- **After creating the key, it is recommended to write down or copy this key in order to send it to a trusted person in a secure way.
- The set global encryption key will not be displayed in the application settings.
- A message is encrypted if the "Lock" icon is displayed next to it after it has been sent.
- After changing/deleting the encryption key, all messages that have been encrypted will be unreadable. To decrypt them, you will need the same encryption key used to encrypt them.
The Encryption Scheme function will determine what a person without an encryption key will see when they receive an encrypted SMS. If the Russian language (or Belarusian, Ukrainian and some others) is selected in the phone settings, the "Russian words" encoding scheme will be used by default. Otherwise the Base64 encoding scheme will be used by default. To change settings for this function, you should select "Encoding scheme" item in the application settings. In the window that opens, select the scheme from the list. There are three encoding schemes:
- Base64
- Cyrillic Base64
- Russian words
The most secure one for Russian-speaking users is "Russian words". The message sent appears to be a set of Russian words, numbers, and symbols, preventing it from being automatically recognised by the operator. But this method of encryption can significantly increase the size of the message, which in turn can lead to sending an additional SMS-message.
With "Base64" encoding, the size of the encoded message will be reduced, allowing more information in the message, but such a message is more likely to be automatically recognised by the operator.
"Cyrillic Base64" is a "compromise" between the probability of detection by an operator and the message size.
Note
A message encrypted with any encoding scheme is almost impossible to decrypt, but the operator can detect the use of encryption and understand that the P-SMS application is being used. The encoding scheme only affects sent messages. Received messages will be decrypted even if the encoding scheme was different from the configured one.
After enabling this function, encrypted messages that you send and receive in all dialogs will be deleted after the set time interval. To display this function, must be set [the global encryption key](#the global encryption key).
To set the time interval for deleting messages, you need to select "Delete encrypted messages after" in the application settings from the "Partisan settings" section. In the opened window select a time interval from the list. To disable this function, in the same window, select "Do not delete".
The "SMS to reset" function is used to reset the partisan settings of the app, after receiving an unencrypted SMS message. This option will prevent intruders from knowing which encryption keys and settings have been applied.
To create/change a "SMS to Reset", select the item "SMS for Reset" in the application settings from the "Partisan settings" section. In the opened window, enter the phrase or message to reset the settings and tap the "Save" button. To delete "SMS to reset", tap the "Delete" button pop-up window.
Warning
Use a phrase or message that no one will accidentally send.
The "Hidden Settings Password" function is needed to hide the partisan settings of the application.
To create/change the password, in the application settings from the "Partisan settings" section, to select the "Hidden Settings Password" item. In the window that opens, enter the password and tap the "Save" button. To remove the password, in the window that opens, tap the "Delete" button.
Note
- After closing the application, the Partisan settings of the application will be hidden.
- To enable the Partisan settings, open the application, enter the password in the "Search in inbox" field and tap the "OK" or "Enter" button in the form of an arrow on the keyboard.
You can set up a separate encryption key for each contact. To do this, select a dialog in the "Inbox" section, tap the button with 3 dots, at the top right, select "Encryption key" item and set it up in the same way as [the global encryption key](#the global encryption key).
Note
- If an encryption key is set for a contact, messages will be encrypted and decrypted by this key even if the global encryption key is set.
For each contact, can select an encoding scheme different from the global one. To do that, select the dialog in the "Inbox" section, tap the button with 3 dots at the top right and select "Encoding scheme" item and set it up in the same way as [the global encoding scheme](#encoding scheme).
After enabling this feature, the encrypted messages you send and receive in the dialog will be deleted after the specified time interval. To display it, the "Encryption key" for contact must be set in the dialog.
To set the time after which the messages will be deleted, it is necessary to select the dialog in the "Inbox" section, tap the button with 3 dots at the top right. Tap "Delete Encrypted Messages After" item and select a time interval from the list in the opened window. To disable this function, in the same window, select the "Do not delete" item.
After enabling this feature, all received messages in the dialog will be deleted after the specified time interval.
To set the time after which the messages will be deleted, it is necessary to select the dialog in the "Inbox" section, tap the button with 3 dots at the top right. Tap "Delete Received Messages After" item and select a time interval from the list in the opened window. To disable this function, in the same window, select the "Do not delete" item.
After enabling this feature, all sent messages in the dialog will be deleted after the specified time interval.
To set the time after which the messages will be deleted, it is necessary to select the dialog in the "Inbox" section, tap the button with 3 dots at the top right. Tap "Delete Send Messages After" item and select a time interval from the list in the opened window. To disable this function, in the same window, select the "Do not delete" item.