Yeah, hash code is a cryptic line of text based on the inputs of the shopping cart. The most common algorithms they use for hashing these days are MD5 or SHA-256.
In the event if hash was present the only way to carry out the hack was to know how the hash was exactly created, what are the inputs used to make the hash which is next to impossible to figure out making it extremely secure. The speciality of hashes is that it can’t be decrypted, so no it’s not feasible.
Yeah, depending on the encryption bit 1024, 2048 or 4096 the amount of decryption time will increase.