Preventing fraud during an offline transaction by encoding a randomly-generated card verification code onto a smart card. The verification code is transmitted to a contactless device during each transaction, wherein it is cross-referenced with the account number to ensure presence of the card. Also, every transaction record is signed by an access key resident on the contactless device and certified by a signing key resident on a remote system. Funds may be deposited onto the card when the contactless device creates a deposit request, signs the request using an access key and transmits it to the remote system, which in turn processes the request and certifies it with a signing key. Funds may be withdrawn when the contactless device creates a withdrawal record and signs it using an access key. The remote system verifies the signatures and certifies the records using a signing key when the records are later transmitted.