A method of processing a payment transaction at a data processing apparatus, comprising: receiving transaction data for the payment transaction, where the transaction data includes at least card track data; when a network connection problem occurs between the data processing apparatus and an issuer, encrypting the transaction data at the data processing apparatus using an encryption key of a cryptographic key pair to generate encrypted transaction data, where the cryptographic key pair includes the encryption key and a decryption key and the decryption key is stored in a hardware security module connected to the data processing apparatus; storing a plurality of copies of the encrypted transaction data in a plurality of storage devices, where each storage device is a distinct external server in a distinct geographic location; identifying transaction data that is encrypted by the encryption key; determining the encryption key is not being used to encrypt new transactions; determining that there are no pending authorizations of the transaction data encrypted with the encryption key to be processed by the issuer; decrypting the identified transaction data at the hardware security module using the decryption key; deleting the decryption key; generating a new cryptographic key pair, where the new cryptographic key pair includes a new encryption key and a new decryption key stored at the hardware security module; and encrypting the decrypted transaction data using the new encryption key; redistributing the newly encrypted transaction data to the plurality of storage devices; periodically attempting to connect to the issuer and if the process successfully connects to the issuer receiving an instruction to submit the transaction data for processing; decrypting the newly encrypted transaction data at the hardware security module using the new decryption key; submitting the newly decrypted transaction data for processing by the issuer; receiving, from the issuer, an indication that the newly decrypted transaction data has been processed; and in response to receiving the indication, deleting the new decryption key from the hardware security module. receiving transaction data for the payment transaction, where the transaction data includes at least card track data; when a network connection problem occurs between the data processing apparatus and an issuer, encrypting the transaction data at the data processing apparatus using an encryption key of a cryptographic key pair to generate encrypted transaction data, where the cryptographic key pair includes the encryption key and a decryption key and the decryption key is stored in a hardware security module connected to the data processing apparatus; storing a plurality of copies of the encrypted transaction data in a plurality of storage devices, where each storage device is a distinct external server in a distinct geographic location; identifying transaction data that is encrypted by the encryption key; determining the encryption key is not being used to encrypt new transactions; determining that there are no pending authorizations of the transaction data encrypted with the encryption key to be processed by the issuer; decrypting the identified transaction data at the hardware security module using the decryption key; deleting the decryption key; generating a new cryptographic key pair, where the new cryptographic key pair includes a new encryption key and a new decryption key stored at the hardware security module; and encrypting the decrypted transaction data using the new encryption key; redistributing the newly encrypted transaction data to the plurality of storage devices; periodically attempting to connect to the issuer and if the process successfully connects to the issuer receiving an instruction to submit the transaction data for processing; decrypting the newly encrypted transaction data at the hardware security module using the new decryption key; submitting the newly decrypted transaction data for processing by the issuer; receiving, from the issuer, an indication that the newly decrypted transaction data has been processed; and in response to receiving the indication, deleting the new decryption key from the hardware security module.