Enabling secure transactions with an underpowered device

1. A mobile device, comprising:

a battery;

a display; and

one or more hardware processor coupled to a non-transitory memory and configure to execute instructions to cause the mobile device to perform operations comprising:

obtaining, through an application installed on the mobile device, an optical machine-readable representation identifying a payment account;

presenting the optical machine-readable representation identifying the payment account on the display in response to a charge level of the battery being below a first predetermined threshold;

maintaining presentation of the optical machine-readable representation identifying the payment account on the display; and

removing the presentation of the optical machine-readable representation identifying the payment account in response to the charge level of the battery being above a second predetermined threshold.

2. The mobile device of claim 1 wherein the operations further comprise:

determining that the charge level of the battery is below a third predetermined level; and

in response to the determining, generating the optical machine-readable representation.

3. The mobile device of claim 1 , wherein the display includes a bistable display.

4. The mobile device of claim 1 , wherein the optical machine-readable representation further identifies a limitation indicator limiting a transaction based on the optical machine-readable representation.

5. The mobile device of claim 4 , wherein the limitation indicator identifies a price limit of an item purchasable based on the optical machine-readable representation.

6. The mobile device of claim 4 , wherein the limitation indicator identifies a geographical region in which the transaction based on the optical machine-readable representation is permitted.

7. The mobile device of claim 1 , wherein the optical machine-readable representation includes a QR code or a bar code.

8. A non-transitory machine-readable medium having stored thereon machine-readable instructions executable to cause a machine to perform operations comprising:

obtaining, through an application installed on a user device, an optical machine-readable representation identifying a payment account;

presenting the optical machine-readable representation identifying the payment

account on a display associated with the user device in response to a charge level of a battery associated with the user device being below a first predetermined threshold;

maintaining presentation of the optical machine-readable representation identifying the payment account on the display; and

removing the presentation of the optical machine-readable representation identifying the payment account in response to the charge level of the battery being above a second predetermined threshold.

9. The non-transitory machine-readable medium of claim 8 , wherein the optical machine-readable representation further identifies a use limitation limiting a transaction based on the optical machine-readable representation.

10. The non-transitory machine-readable medium of claim 9 , wherein the use limitation limits the transaction based on the optical machine-readable representation to purchases under a price limit.

11. The non-transitory machine-readable medium of claim 9 , wherein the use limitation limits the transaction based on the optical machine-readable representation to purchases associated with a merchant.

12. The non-transitory machine-readable medium of claim 8 , wherein the display includes a bistable display.

13. The non-transitory machine-readable medium of claim 8 , wherein the optical machine-readable representation includes a QR code or a bar code.

14. A method comprising:

obtaining, through an application installed on a user device, an encoded image identifying a payment account of a user;

presenting the encoded image identifying the payment account on a display of the user device in response to a charge level of a battery associated with the user device being below a first predetermined threshold;

maintaining presentation of the encoded image identifying the payment account on the display of the user device; and

removing the presentation of the encoded image identifying the payment account in response to the charge level of the battery being above a second predetermined threshold.

15. The method of claim 14 wherein the encoded image includes a security question that is legible, wherein the security question is randomly selected from a plurality of security questions.

16. The method of claim 15 , wherein the encoded image includes an answer to the security question.

17. The method of claim 14 , wherein the encoded image includes a QR code or a bar code.

18. The method of claim 14 , wherein the charge level below the first predetermined threshold is insufficient to power a hardware processor of the user device.

19. The method of claim 14 , further comprising:

determining that the charge level of the battery is below a third predetermined level; and

generating the encoded image in response to the determining.

20. The method of claim 14 , wherein the encoded image includes a human-readable code that identifies the payment account.