AWS CloudHSM vs Vault: What are the differences?

Developers describe AWS CloudHSM as "Dedicated Hardware Security Module (HSM) appliances within the AWS cloud". The AWS CloudHSM service allows you to protect your encryption keys within HSMs designed and validated to government standards for secure key management. You can securely generate, store, and manage the cryptographic keys used for data encryption such that they are accessible only by you. AWS CloudHSM helps you comply with strict key management requirements without sacrificing application performance. On the other hand, Vault is detailed as "Secure, store, and tightly control access to tokens, passwords, certificates, API keys, and other secrets in modern computing". Vault is a tool for securely accessing secrets. A secret is anything that you want to tightly control access to, such as API keys, passwords, certificates, and more. Vault provides a unified interface to any secret, while providing tight access control and recording a detailed audit log.

AWS CloudHSM can be classified as a tool in the "Data Security Services" category, while Vault is grouped under "Secrets Management".

Some of the features offered by AWS CloudHSM are:

• Protect and store your cryptographic keys with industry standard, tamper-resistant HSM appliances. No one but you has access to your keys (including Amazon administrators who manage and maintain the appliance).
• Use your most sensitive and regulated data on Amazon EC2 without giving applications direct access to your data's encryption keys.
• Store and access data reliably from your applications that demand highly available and durable key storage and cryptographic operations.

On the other hand, Vault provides the following key features:

• Secure Secret Storage: Arbitrary key/value secrets can be stored in Vault. Vault encrypts these secrets prior to writing them to persistent storage, so gaining access to the raw storage isn't enough to access your secrets. Vault can write to disk, Consul, and more.
• Dynamic Secrets: Vault can generate secrets on-demand for some systems, such as AWS or SQL databases. For example, when an application needs to access an S3 bucket, it asks Vault for credentials, and Vault will generate an AWS keypair with valid permissions on demand. After creating these dynamic secrets, Vault will also automatically revoke them after the lease is up.
• Data Encryption: Vault can encrypt and decrypt data without storing it. This allows security teams to define encryption parameters and developers to store encrypted data in a location such as SQL without having to design their own encryption methods.

Vault is an open source tool with 13.2K GitHub stars and 1.98K GitHub forks. Here's a link to Vault's open source repository on GitHub.