Welcome to our fifth lesson of the year! I am sure that you all have been studying hard, as you will be taking your midterm at the end of this lesson. But before we get to that, we have some content to cover, so let’s get started. Given today's lesson topic of secrecy and concealment, I am sure that most of you have an idea of which topics we will be dealing with already. I want to start with a quick overview of the historical perspective of why exactly witches and wizards need to conceal their existence - and we will discuss spells that go along with this idea. Professor Becker assured me that you have already covered the International Statute of Secrecy in depth in Year Three of History of Magic, so I am sure that you know what it entails.

Because of the Statute of Secrecy and the threat of persecution, many spells were invented to hide one's activities. However, the spells that we will be dealing with today not only cover the process of hiding one's existence but include many other possibilities as well. While some applications are harmless, others are used for the purpose of harming others. Magic enables us to do many different things. We may hide a present we do not want a loved one to find before their birthday, but we may also hide traces of magic that have been imbued into an object. Though it is a rare ability, some witches and wizards are able to recognise the miniscule traces of active magic that always remain when an enchantment is active. There are spells to do the same thing, naturally, and many adult witches and wizards have taken to checking objects for foreign magic. This is a simple way to detect pranks, but also much more harmful magic. The issue of secrecy and concealment is an ever-changing, interactive process. As soon as new concealment or secrecy spells are discovered, researchers start looking for possible counters to them. The dynamics of this process are wonderful in so far that the research area of secrecy spells is the most lively one, and possibly one of the most important ones.

When we are simply taking a look at how to, for example, disguise your Hogwarts spell books from Muggle guests who are unaware of magic, it is unnecessary to look into complicated concealment charms. Non-magical methods of revealing messages do not work on magically concealed information. In magical families, the need for these secrecy spells exists to a greater degree. Probably the most common applications are parents concealing information that their children should not access, or, talking about sibling rivalries, using invisible ink for one's diary. I am certain that some of you have tried similar things already if I am interpreting these smirks correctly. Naturally, if you were to attempt to reveal the secrets that a First Year student tried to hide, you would succeed. Most enchanted diaries that you can buy actually include charms that exceed the abilities of Hogwarts students, but are easy enough to reveal for an adult witch or wizard. You ought to be old enough to know that this does not mean that you need to panic due to the possibility of your parents reading your diary; most of these store-bought books include a safety feature that will tell you if the contents have been revealed. What we are going to focus on today, however, is not how to break into your little siblings' diaries. We will focus on concealment charms in general, but also deal with how to seal letters so that they only open for the addressee. Naturally, there are also more advanced locking charms which we will not study, and the question of how to turn yourself invisible.

Concealment Charms

Concealment charms are spells which are used to conceal things from view, be it writing or objects. Additionally, they contain those spells that are used to disguise the magical properties of an object. The term ‘concealment charms’ is used as an umbrella term for many different spells, some of which you will be learning about today.

Thinking about last lesson as well as the Revealing Charm you learned back in Year One, there are many ways of revealing writing that has been magically concealed. Today, we will focus on how to make a text disappear or make it illegible - and there are uncountable ways of doing so. Encrypting texts is possible by simple means such as the non-magical Caesar cipher, and continue in complexity up to spells that require both sender and addressee to use the same spell tweak.

There is only one spell in general, but the important thing here is that it is a spell that is easily varied. The charm is using a password to conceal information, and it is tweaked a little by adding the exact password that you will need to decipher the message by the means of concentration. By letting your intended addressee know about it, they will be able to decipher your message - but only them. Due to the sheer number of possible variations, it is highly unlikely that anyone who finds your encrypted message will be able to read it. Instead, it will show up as a jumbled mix of characters that do not make any sense. We will not cover the mechanics of how exactly the encryption process works, but rest assured that it is a relatively secure method.

As for the spell's name, it is as unremarkable as the spell's effects: it is called the Obscuring Charm.

The concentration part here makes it impossible to reveal the information with a simple Aparecium. Think of it as a mechanical lock that needs to be opened with a certain key. It is your concentration that shapes the lock in the form that only allows one key to open it. There are limitations on how much information may be obscured, the maximum when it comes to how many chunks of information (i.e. words, phrases, or even sounds or ideas) you can concentrate on is seven. To decipher the code, you will have to concentrate on up to seven chunks to open the “magical lock” of concealment.

Another charm, that I mentioned last lesson, is Wight’s Doubt. To remind you, the function of this spell is to conceal writing by applying a covering layer. As the spell is countered easily, its original purpose was to serve as a prank: people, mostly Hogwarts students, would buy parchment covered with Wight’s Doubt and lend it to their friends for their assignments. As the spell is countered, any writing upon the magical layer will be lost irrevocably. Naturally, this caused a lot of outrage, but nowadays, Wight’s Doubt is a favoured study aid as it enables you to easily conceal, for example, ink stains on your homework assignment. Remember to be careful though, you do not want to lose any of your work.

The spell is dynamic, and you may refer to the following photograph to get an idea of how Wight’s Doubt is applied to a parchment.

The spell is about as wide as the Muggle correction tape depicted above, so you may need to go back and forth a couple of times when you cast it for full coverage. Charmed rolls of parchment will take a long time to create, yet I have been told that they are still popular amongst some young pranksters. Wight’s Doubt may come in any colour or texture and, depending on your concentration, will blend in perfectly even with patterned paper.

From what we’ve talked about so far, it would be not too far off to assume that concealing charms are only used to conceal writing, despite the definition I gave you earlier this lesson.  However, they are by no means this limited. In fact, let us take a look at charms to conceal an object’s magical properties next.

There are multiple reasons why one might decide to disguise the magical properties of an object. Prank objects are naturally an application, but these spells are used most commonly by Muggle-born witches and wizards and those of us who decide not to live in a fully magical neighbourhood. If it is not apparent that an object is magical, there is no issue in displaying it even with Muggles around. Up to now, no concealment charm has been found that is good enough to fool measures such as secrecy sensors and probity probes, but there are plenty that will conceal enchantments sufficiently such that they cannot be detected unless someone actively searches for them.

If you analyse the spell’s components, you will recognise one of its biggest flaws: it does not work when it comes to concealing enchantments that are not spell-based. The incantation is composed of two Latin words, condidi meaning “conceal/hide/keep safe,” with carmen being a translation of “charm.” It might appear contradictory to apply a further enchantment to conceal magic, yet it creates a kind of bubble that shields the enchanted objects from detecting spells. Your willpower is essential here as it ensures a sufficient strength for your spell.

Next, I want to discuss concealing areas from view. While we already discussed some enchantments and wards last year, there are more ways to obfuscate areas. To name a few charms that you know already, the Hidden Homes Charm and Fidelius Charm belong to the category of concealment charms. Less powerful than the Hidden Homes Charm, the Permeable Barrier Charm is used to conceal places from Muggles. Despite its name, it does not only create a barrier, but also an illusion that conceals the entire existence of the target. Mostly used for events like hiding the stadium for the Quidditch World Cup, a big advantage of this charm is that it is not anchored to a single person, but a place - and that it allows every witch, wizard, and squib to pass through it.

While every user of magic is able to pass through this charm, there are different theories on how the charm works. Some researchers claim that it is the magical heritage that is judged, and that squibs still have the ability to interact with magic to a certain degree: they may still use magical devices. Others assume that it is the knowledge of the magical world that allows them through the barrier. It is uncertain which of these theories is the correct one, if one of them is true at all.

Variations of this spell exist, and they allow you to create barriers of all possible kinds. Using almost the same spell block, except for a changed incantation, you may use Femina Commeabilitum (FAY-me-nah come-may-ah-BILL-ee-tum) to conceal a place from everyone but women, or Adulta Commeabilitum (ah-DOOL-tah come-may-ah-BILL-ee-tum) for an age line that will not allow those younger than seventeen to even see the enclosed area. If accompanied by someone permitted through the barrier, other people may be taken inside the enchantment.

To further conceal some areas from Muggle eyes, workers from the Ministry of Magic often combine the Permeable Barrier Charm with further means to conceal a place’s existence. It is often foggy in Great Britain - which is why a fog barrier was created to obscure a place without arousing any suspicion. As the picture below shows, visibility may decrease immensely so that no one would even think about questioning why they were unable to see through it. As it is a patented charm available only to those working for the Ministry of Magic, I am unfortunately unable to teach you the Ministry of Magic Fog Barrier, but I at least wanted to present it to you.

The best-known application of the Permeable Barrier Charm, along with a myriad of other concealment charms, is a sad tale, namely that of the creation of the fortress of Azkaban. Built by a wizard known only as Ekrizdis in the early fifteenth century, no one knew about its existence until well after its owner’s death. Ekrizidis is labeled a Dark wizard, and was highly paranoid. Next to concealing his island from everyone but those of his bloodline (meaning only himself, as he was the last living member of his family), he additionally made it Unplottable and cast a multitude of other spells with the sole purpose of making his island a private place no one but him could access. He lured countless Muggle sailors to the island, then tortured and killed them. I will not go into details, as they are irrelevant to our discussion today and frankly too disturbing to bring into the classroom.

Concealment Charms vs. The Concealing Charm

As we are talking about concealment charms, I want to point out the difference between concealment charms and the Concealing Charm. You know from previous years that it is essential to pay close attention to details, and this is no exception to the rule.

The Concealing Charm is a concealment charm used to turn ink invisible. Take a look at the spell block before we move on to discuss the difference between the two terms.

At its most basic, the difference we are talking about here is a difference between a single charm and a category of spells. An example from earlier years would be flight charms as a category, and the Levitation Charm a single charm within that category. This term is easy enough to distinguish because the names differ a lot - yet when it comes to concealment, both terms are unfortunately very similar. I ask you to pay especially close attention to this, as you should not confuse the two.

Enclosing an area

Sometimes, concealment is not a viable option. Nevertheless, secrecy needs to be upheld when it comes to, for example, certain sensitive information that ought not to be shared with everyone. There are many appliances that are specifically made to listen in to private conversations, however, the most popular one among teenagers is most likely Extendable Ears. Many other methods, both magical and Muggle, exist that all work to get access to a sealed room to eavesdrop. The easiest way to prevent this from happening is by sealing the room magically, creating a barrier that cannot be crossed. The downside is that this barrier works both ways: nothing can get into your room, but you will be unable to send anything out, either.

The barrier that is created is quite special in its properties. Nothing can pass through it, not solid objects, sound, particles, light, or even magic. If you were to cast Lumos Solem to create a flashlight, a person on the other side of an imperturbable barrier would not even notice a speck of light. No sound will be heard and spells cast at a barrier will dissipate upon contact. Theoretically speaking, you create a fully isolated system. If we talk about real applications though, you will notice that due to the amount of willpower that is necessary, no witch or wizard should be able to put an Imperturbable Charm around a room that is big enough for a meeting of any kind. This is why it is mainly doors and windows on which this charm is cast: they are the natural weak points of any room. Given enough participants, it is possible to cast an Imperturbable Charm on an entire room. However, it is nearly impossible to seal a room completely; there will always be ‘cracks,’ so to speak. While this is a minor security risk, it makes the spell much safer. Otherwise, the barrier would be complete and would not even let the smallest molecules pass, including oxygen - and a room’s oxygen supply is limited.

When it comes to communication, especially Muggle-raised students often raise the concern of the safety of owl post when it comes to passing on confidential information. I see some of you nodding and I understand your worries. Yet, no one is likely to steal a letter from you and - let’s face it - even if someone did find out the name of your crush by intercepting a letter meant for a friend or parent, it would not cause any problems on a larger scale. This is why we only use wax seals, as they will notify you of someone reading your letter, yet do not provide any security measures. For ministerial communication and official letters such as certificates, notices from the Improper Use of Magic Office, or confidential letters between a lawyer and their client, this is not sufficient. A skilled witch or wizard may open a wax seal without you being able to notice the difference. To make confidential information safer, the Parchment Sealing Charm was developed.

The spell as it is presented here will seal the parchment seamlessly, and opening it will require physically tearing the parchment. This does not require a certain person to open the letter though, the only thing that is guaranteed by the Parchment Sealing Charm is that you will know for sure whether your letter has been opened once before. Casting the spell will create a watermark on the parchment, and casting it a second or third time will add a second or third mark, which are easy to see. For increased security, these letters are often charmed with multiple charms. If combined with the Obscuring Charm, it will be hard or even impossible to make out the original message if you do not know the key. Other strategies include applying Wight’s Doubt on a letter and writing a fake message on top of it. I am certain many other methods exist, but naturally those are closely guarded secrets and not accessible to the public.

Covering your tracks

As a last spell for today, I want to take a look at something that many people tend to forget when first trying to conceal themselves: their footsteps. Take a second and think about every aspect of your being that you need to consider to conceal yourself completely. Sight, obviously, but what about the sound of your breathing or your heartbeat? The smell of your perfume or, if you do not use any, the specific smell of your body? The draft of air that your breathing creates? The imprint of your feet on the carpet? Your shadow? There are many aspects that you need to think about, and especially in winter months, you need to be extra careful if you ever decide to trail someone: your footsteps in the snow can give you away, even if you considered everything else. To remove these, you may use the Obliteration Charm.

While the most common application is to remove footsteps in the snow, the spell works on any depressible surface. No new substance is created, but it rather undoes the disturbance created by your step: your weight creates pressure which causes the snow, sand, or other material to compress. The Obliteration Charm undoes this compression and hence covers all tracks that might point at your position.

That’s it for today! We have covered many new spells, so make sure that you review your notes on them before attempting your midterm. Additionally, you will need to do a regular quiz on this lesson’s contents, and you may participate in an extra credit game. Good luck on your midterms, and see you next week!

Professor Cassandra Virneburg

Image sources: here, here, here and here.