sichern
to secure
To protect something from danger, loss, or damage; to make something safe.
Die Feuerwehrleute sicherten das einsturzgefährdete Gebäude.
The firefighters secured the building that was at risk of collapse.

to secure / save
Loading your saved state.
to secure
To protect something from danger, loss, or damage; to make something safe.
Die Feuerwehrleute sicherten das einsturzgefährdete Gebäude.
The firefighters secured the building that was at risk of collapse.

The verb 'sichern' (to secure) is derived directly from the adjective 'sicher' (safe/sure). So the act of 'Sichern' (securing) always has the goal of bringing something into a safe state.
Bist du sicher, dass du die Tür abgeschlossen hast?
Are you sure you locked the door?
If you want to express what something is being protected from, you use the prepositions 'vor' (from) or 'gegen' (against). The preposition is always followed by the dative with 'vor' and the accusative with 'gegen'.
Man sollte sein Haus vor Einbrüchen sichern.
You should secure your house against break-ins.
In the meaning 'sich etwas verschaffen' (to obtain something for oneself), 'sichern' is used reflexively with a dative pronoun and an accusative object. The structure is: subject + sichert + sich (dative) + etwas (accusative).
Die Mannschaft sicherte sich den Sieg in letzter Minute.
The team secured the victory in the last minute.
In connection with computers, programs, and data, 'sichern' almost always means 'speichern' (to save). Watch for words like 'Datei' (file), 'Dokument' (document), or 'Festplatte' (hard drive).
Ich muss meine Fotos schnell auf einer externen Festplatte sichern.
I need to quickly save my photos on an external hard drive.
In a police or criminological context, 'sichern' means collecting and preserving traces or evidence. Typical words in this context are 'Tatort' (crime scene), 'Spuren' (traces), and 'Beweismittel' (evidence).
Die Ermittler konnten am Tatort wichtige Spuren sichern.
The investigators were able to secure important traces at the crime scene.
In a sports context, especially in climbing or mountaineering, 'sichern' has the specific meaning of protecting another person from falling with a rope.
Beim Klettern ist es lebenswichtig, den Partner korrekt zu sichern.
When climbing, it is vital to belay your partner correctly.
to protect
'schützen' and 'sichern' both have to do with safety. 'schützen' is used when someone or something is kept safe from danger, harm, or negative influences. The focus is on the danger. 'sichern' often means to make something safe, fasten it, or protect it from loss. For example, you can 'sichern' data, a door, a place, or, when climbing, a person with a rope. The words can be confused because both can keep something from harm. In practical terms: 'schützen' fits protection from a danger, while 'sichern' fits fastening, saving, or guaranteeing.

Zu Hause sichert Julian die Fotos auf einer externen Festplatte.
At home, Julian backs up the photos on an external hard drive.
Beim Radfahren schützt sie ihren Kopf mit einem Helm.
When cycling, she protects her head with a helmet.