In terms of encryption uses, HSMs encompass two main categories: payments and general-purpose. HSMs are used to process payment transaction data and manage the encryption keys involved. They can also be used to issue card and mobile EMV credentials.
Hardware security modules also specialize in key management. That is to say, logically managing the encryption keys used to encrypt and decrypt data. This process involves the use of algorithms to create encryption keys, distribute those keys to different applications, and then set policies that determine when keys should be retired from use, and ultimately deleted. Additionally, users can also configure HSMs to generate asymmetric key pairs. This means that a public key is used to encrypt data and a private key is used to decrypt it. Users can also secure the private key and establish a certificate authority (CA) in the process.
Put plainly, hardware security modules are used to establish complete and total network security for organizations of all sizes.