Technologies for split key security include a payment device to generate a key encryption key and a first key encryption key part. The payment device generates a second key encryption key part based on the key encryption key and the first key encryption key part and deletes the key encryption key in response to generating the second key encryption key part. Further, the payment device stores the first key encryption key part to a secure memory of a security co-processor of the payment device and the second key encryption key part to a secure memory of a secondary processor of the payment device. The secondary processor is electrically coupled to a backup energy source.