Which encryption algorithm is sensitive to an attacker having access to it? We are contemplating hiding a sensitive information from our business partner by encrypting it.
However, customers have access to both the sensitive and the encrypted information. Furthermore, they can influence the 'sensitive information' to their liking.
I am curious which security algorithms are sensitive to an attacker being able to encrypt whatever they choose to (and see the result). Also, is there a known guide (or a googleable name) of this property of crypto algorithms?
I am curious which security algorithms are sensitive to an attacker being able to encrypt whatever they choose to (and see the result).

No algorithm would be considered secure if they could be broken under that assumption.

Also, is there a known guide (or a googleable name) of this property of crypto algorithms?

There's a couple of different names (based on some fairly subtle distinctions); the most common is probably &quot;IND-CPA&quot;, which stands for &quot;indistinguishable from random against chosen plaintext attacks&quot;, that is, even if the attacker was allowed to submit large number of plaintexts of their choosing and get them encrypted, they still would be unable to obtain any information about the encryption method (it'd still look &quot;random&quot;)