Transform Secrets Engine
Part of Vault's Advanced Data Protection solutions, Transform provides mechanisms for transforming sensitive information to protect it even as it lives outside Vault's sphere.
Transform consists of three modes, called transformations. Format Preserving Encryption (FPE) for encrypting and decrypting values while retaining their formats. Masking for replacing sensitive information with masking characters. And Tokenization which replaces sensitive information with mathematically unrelated tokens.
Comparison to Transit
Transit implements many traditional cryptographic primitives, such as AES encryption and RSA signatures (among others). Transform implements solutions to protect sensitive values in more narrow, but still critical use cases.
What Solution When?
When should one use a particular transform or transit encryption? Based on your use case and its requirements, this flowchart can help you choose the right solution.
Keep in mind that unlike all other solutions, Tokenization is stateful, and all values must be stored either within Vault or a supported external store. As such all other solutions will outperform and outscale tokenization.