What Is an Encryption Key?

What Is an Encryption Key?

 By Charles Joseph | Cybersecurity Advocate
 Last update: November 25, 2023

An encryption key is a piece of information, typically a string of characters or a binary value, used in encryption algorithms to convert plaintext (readable data) into ciphertext (unreadable data) and vice versa.

It serves as the basis for securing data during storage or transmission, ensuring that only authorized parties can access the original, readable information.

Here’s what else you should know about encryption keys:

Key Types

There are two types of encryption keys – symmetric and asymmetric.

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Symmetric keys use the same key for both encryption and decryption, while asymmetric keys use a pair of related keys (public and private keys) for encryption and decryption.

Key Length

The strength of the encryption depends on the key length, which is measured in bits. A longer key provides stronger encryption, making it more resistant to brute-force attacks.

Common key lengths are 128, 192, or 256 bits for symmetric encryption and 2048 or 3072 bits for asymmetric encryption.

Key Management

Proper key management is crucial for maintaining the security of encrypted data.

This involves securely generating, storing, distributing, and retiring keys. Key management systems (KMS) are often used to automate and facilitate these tasks.

Key Rotation

Periodically changing encryption keys (key rotation) helps to minimize the impact of key compromise and maintain security over time.

Key rotation policies differ depending on the organization’s security requirements and the type of data being protected.

Key Exchange

Securely exchanging encryption keys between parties is vital to prevent unauthorized access.

Key exchange protocols, such as the Diffie-Hellman algorithm, allow parties to securely establish a shared key over an insecure communication channel.


Understanding encryption keys and their management is essential for maintaining data privacy and security in the digital world.

"Amateurs hack systems, professionals hack people."
-- Bruce Schneier, a renown computer security professional