Documentation : Pocket Quick Guide : Encryption

The 'blue lock' image of the node means that this node is protected with encryption and that you need to enter the password in order to expand it (i.e. read its content)

Type the password in this orange field and then press enter or tap the 'keys' icon

The 'keys' icon indicates that you have selected an encrypted node which is not open yet. Therefore you need to enter the password in order to see the node's content. After you enter the right password and the node is open it will stay open until you close the document or tap tiny orange 'lock' icon on top right of the 'magnifier' image

You can turn encryption on and off by means of the 'node properties' tool. There you can also change the password of encrypted nodes