If this is something that already has a name, please tell me to look at that, but I have not been able to find one yet.
I am considering this process for storing some data securely. I want to provide a way that neither party can decrypt the value by themselves, ( and no way for the original value to be retrieved if only 1 parties storage is compromised ), but would need a portion of the key provided by both parties in order to decrypt it.
The data stored will be near to but less than 128 bytes.
Party A ( Adam ) will generate a 128 byte key ( Key A ) and share it temporarily with Party B over TLS.
Party B ( Bob ) will generate a 128 byte key ( Key B), use that to One-time pad the "Secret Information! " creating "Bob's Secret Information".
Party B ( Bob ) will user Adam's Key to One-time pad the "Bob's Secret Information" creating "Adam&Bob's Secret Information"
Party B ( Bob ) will discard Key A, then store Key B and return "Adam&Bob's Secret Information" to Adam over TLS.
( Or that is equally to say: Bob will Combine Key A and Key B into Key AB - then protect the Secret, creating "AB Secret", then discard Key AB and A, keeping only Key B )
When Adam later wants to use the "Super Secret Information" to do something, he will send "Adam&Bob's Secret Information" and Adam's Key A to Bob over TLS, and Bob will decode the secret information and return it over TLS.
This process would not re-use any key, and each piece of information stored would have new keys generated by both parties.
This looks remarkably like the classic simple example I remember seeing of how DH key exchange works ( sending locked padlocks and keys ), but being done with Symmetric keys instead of Asymmetric.
So, is anyone aware of any obvious flaws with this process that I am just missing, or does it already have a name?