ENCRYPTBYPASSPHRASE in T-SQL takes a passphrase as a parameter. I’m wanting to encrypt some data in the same way outside of SQL server, in such a way as said data may be decrypted using the DECRYPTBYPASSPHRASE function once ingested into SQL Server.

I can’t however find any reference to how SQL Server (>= 2017) derives the key from the passphrase.

Does anyone know how this is done (e.g. using PBKDF2, what salt, how many iterations)? or where I can easily find this info?