Magic Storage Encryption is the magical equivalent of file encryption, and in fact predates it by several millennia. Magic storage encryption by default limits the use of a magic scroll to only the one who created it. In order to create the alternative, an unencrypted scroll, one must employ some method of isolation of the scroll from one's own thoughts while creating it.
The default for magic scrolls is that they are encrypted. The creation of a spell scroll manually will always carry with it the memory of creating it. Absolute darkness with a single candlelight, absolute silence, and absolute solitude and seclusion are the preferred environment for creating a spell scroll. The presence of any distraction, noise, or intrusion will be permanently etched into the spell scroll, and must be recalled whenever using it. That memory, being inextricable from intent in recalling the magics within, essentially means that a spell scroll can normally only be used by the one who created it.
This is rarely ever a serious problem, as most mages would want to create their own scrolls anyway. But this does mean that no mage can use a different mage's spellbook. A mage may certainly read another's spellbook and upon understanding the spells within, copy them with no other reference material. But a mage cannot directly channel these magics.
One commonly employed method is the use of vimancy to create a spell scroll by moving a pen or stylus remotely. In essence this causes the potentia itself to be regarded by the scroll as its author, which has the effect of allowing anyone to trigger the scroll using solely the potentia contained within itself. A mage cannot directly use another's spellbook unless the spellbook is designed to be unencrypted. Some spellbooks are made this way on purpose and loaned to students in order to familiarize them with the act of casting spells.
When casting magic from an encrypted scroll, the mage must recall the memory of creating the scroll as well as the magic itself. For this reason,