The invention discloses cloud-based transactions methods and systems. Techniques for enhancing the security of a communication device when conducting a transaction using the communication device may include using a limited-use key (LUK) to generate a transaction cryptogram, and sending a token instead of a real account identifier and the transaction cryptogram to an access device to conduct the transaction. The LUK may be associated with a set of one or more limited-use thresholds that limits usage of the LUK, and the transaction can be authorized based on at least whether usage of the LUK has exceeded the set of one or more limited-use thresholds.