
der Key
key
A string of characters, a code, or a password needed to encrypt and decrypt data or to access a system.
Kannst du mir den Key für das WLAN geben?
Can you give me the key for the Wi-Fi?
key
Loading your saved state.

key
A string of characters, a code, or a password needed to encrypt and decrypt data or to access a system.
Kannst du mir den Key für das WLAN geben?
Can you give me the key for the Wi-Fi?

key
Colloquial for a central, decisive element or the key to success.
Gute Kommunikation ist der Key für eine funktionierende Beziehung.
Good communication is the key to a functioning relationship.
The word 'Key' (key) is an Anglicism and is used mainly in colloquial speech and informal contexts. It sounds modern and is often used by younger people.
Gib mir mal schnell den Key für dein Fahrradschloss.
Quick, give me the key for your bike lock.
The meaning is easy to recognize from context. If people are talking about technology, computers, or security, it means a code or password. If it is about abstract things like success or a good relationship, it means the decisive element.
Ich habe den Product Key für die Software verloren.
I lost the product key for the software.
In the technical meaning, 'Key' (key) is often used as part of compounds, such as 'WLAN-Key' (Wi-Fi key), 'Product-Key' (product key), or 'Lizenz-Key' (license key). Typical verbs are 'eingeben' (to enter), 'brauchen' (to need), or 'haben' (to have).
Du musst den 16-stelligen Key eingeben, um das Programm zu aktivieren.
You have to enter the 16-character key to activate the program.
In the metaphorical meaning, the structure '[something] ist der Key für/zu [etwas]' ([something] is the key to/for [something]) is often used to describe a solution or a decisive factor.
Regelmäßiges Üben ist der Key zum Erfolg.
Regular practice is the key to success.
key / wrench
Schlüssel and Key can both refer to a code used to encrypt or decrypt data. Schlüssel is the standard German word, while Key is used especially in technical or informal language. Schlüssel is usually the better choice in a general text; in a technical conversation, Key may sound more natural.

Im technischen Gespräch erklärt Tom, wie der geheime Key gespeichert wird.
In the technical conversation, Tom explains how the secret key is stored.
In der deutschen Anleitung wird erklärt, wie der geheime Schlüssel gespeichert wird.
The German instructions explain how the secret key is stored.