Systems and methods of code generation and authentication are disclosed here. One embodiment includes receiving a request for a batch of codes, each code being unique for a separate unit item, generating a batch of codes, each code being unique for a separate unit item, wherein a subsection of the code comprises a check value, and encrypting the code. In response to receiving a request to authenticate a code, decrypting the code to access a subsection of the code comprising a check value, comparing the check value to a value to authenticate the code. In one embodiment, the encrypting further comprises encrypting the code with a key, and including a key identifier as a subsection of the encrypted code; and decrypting the code further comprises using the key identifier included in the encrypted code to access the key to decrypt the code. Further more, in one embodiment, the batch of codes are provided to be marked on a plurality of products as at least one of a numeric representation, an alphanumeric representation, or a graphic symbol.