Any reason that Azure Key Vault disallows symmetric key encryption without asymmetric key wrapping it?

Hello @Mat CHAN,

Thank you for posting your query on Microsoft Q&A.

Azure Key Vault (AKV) is designed to provide a high level of security for key management and cryptographic operations. The decision to not support direct symmetric key encryption without using an asymmetric key as a wrap key is likely influenced by several security and design considerations:

1. Security Best Practices: Asymmetric keys provide a higher level of security for key management. By using an asymmetric key to wrap (encrypt) the symmetric key, AKV ensures that the symmetric key is never exposed in plaintext outside the secure environment of the Key Vault. This reduces the risk of key compromise.
2. Key Management: Asymmetric keys are easier to manage securely because the private key never needs to be shared or transmitted. Symmetric keys, on the other hand, require secure mechanisms for distribution and storage, which can be more complex and prone to security risks.
3. Scalability and Performance: Asymmetric key operations are generally more computationally intensive than symmetric key operations. By using asymmetric keys to wrap symmetric keys, AKV can leverage the performance benefits of symmetric encryption for large data while maintaining the security benefits of asymmetric key management.

In summary, the design choice to use asymmetric keys as wrap keys for symmetric keys in Azure Key Vault is driven by a combination of security best practices, key management considerations, and performance optimization. This approach ensures that the keys are managed securely while providing robust encryption capabilities.

https://learn.microsoft.com/en-us/azure/key-vault/keys/about-keys-details

Using an asymmetric key as a wrap key provides an additional layer of security. The symmetric key is encrypted with the asymmetric key, and the asymmetric key is stored in Azure Key Vault. This way, even if the symmetric key is compromised, the data encrypted with that key cannot be decrypted without the corresponding asymmetric key.

I hope this information is helpful. Please feel free to reach out if you have any further questions.

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Thanks,
Raja Pothuraju.