10 Types of Cryptographic Keys

Today’s digital applications depend on cryptographic keys for many different purposes. Understanding different types of cryptographic keys are very handy when it comes to choosing one for a specific task. In this article, I will be discussing the different types of cryptographic keys, their properties, and functions.

So, what is a cryptographic key?

A cryptographic key is simply a string of bits used by a cryptographic algorithm to convert plaintext into ciphertext and vice versa. A cryptographic key is an important part of all cryptographic operations. For example, a key is used in both encryption and decryption of data in a cryptographic system.

This makes cryptographic keys important part of any cryptographic scheme since the general security of such a system depends on the degree of security of the keys used. Cryptographic keys are classified into two.

Symmetric and asymmetric encryption keys.

Symmetric encryption uses only one key which is used in both encryption and decryption of data. On the other hand, asymmetric encryption uses two different keys, one for encryption and the other for decryption purposes.

Cryptographic keys have many uses including data encryption and decryption, digital signature verification, digital signature creation, message authentication, key transport, and key wrapping. Normally the length of a key is expressed in bits.

The longer the key is, the more difficult it is to decode or crack the encrypted data. However, this comes at a cost. Long keys are more time consuming during encryption and decryption operations.

So, when determining the length of the key to go with, consider the following factors:

  • The type of algorithm is used
  • The strength of security required
  • The amount of data to be processed with the key
  • The lifetime of the key

Cryptographic keys can either be static (for long-term usage) or ephemeral (for a single session or transaction). The lifetime of static keys varies from days to weeks, months or even years depending on their purpose.

Thus, it recommended to update or change keys to prevent the risk of an attack as a result of misuse of these keys.

Cryptographic keys

  • The asymmetric key pair – it’s a unique public/private key pair. Data is encrypted using the public key and only the matching private key can decrypt it.
  • Signature keys – are used to generate the digital signature for verifying identity, checking data integrity, and non-repudiation purposes.
  • Authentication keys – are used to verify identity, communication, and data.
  • Wrapping keys – are used to encrypt other keys.
  • Transport key – are used to encrypt transport messages that contain other important keys.
  • Key agreement key – are often used during an exchange of other keys for maximum security.
  • Ephemeral key – is used to establish other keys.
  • Transient key – is simply an asymmetric public/private key pair that is only used once.
  • Master key – is used to generate other keys using a key derivation function.
  • Authorization keys – are used to provide a privilege. They are also used to prove that a message has been successfully decrypted.

Now I want to hear from you.

What do you think of cryptographic keys?

Or maybe I missed an important aspect of these keys.

Either way, let me know by leaving a comment below.


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