Semiconductor device with secure access key and associated methods and systems
Memory devices, systems including memory devices, and methods of operating memory devices are described, in which security measures may be implemented to control access to a fuse array (or other secure features) of the memory devices based on a secure access key. In some cases, a customer may define and store a user-defined access key in the fuse array. In other cases, a manufacturer of the memory device may define a manufacturer-defined access key (e.g., an access key based on fuse identification (FID), a secret access key), where a host device coupled with the memory device may obtain the manufacturer-defined access key according to certain protocols. The memory device may compare an access key included in a command directed to the memory device with either the user-defined access key or the manufacturer-defined access key to determine whether to permit or prohibit execution of the command based on the comparison.
1. A memory device, comprising:
a memory array;
a plurality of nonvolatile memory elements configured to store a first access key; and
peripheral circuitry coupled to the plurality of nonvolatile memory elements and the memory array, and configured to:
receive a predetermined sequence of signals from a host device;
retrieve the first access key from the plurality of nonvolatile memory elements in response to receiving the predetermined sequence of signals;
configure one or more pins to output the first access key; and
transmit the first access key using the one or more pins after configuring the one or more pins.
2. The memory device of claim 1 , wherein the one or more pins are designated for otherwise receiving inputs only.
3. The memory device of claim 1 , wherein the plurality of nonvolatile memory elements includes one or more fuses of a fuse array of the memory device, one or more conductive layers of the memory device, or both.
4. The memory device of claim 1 , wherein the peripheral circuitry is configured to generate control signals for a fuse array of the memory device in response to receiving an access command directed to the fuse array, the access command including a second access key.
5. The memory device of claim 4 , further comprising:
an authentication component coupling the peripheral circuitry with the fuse array, the authentication component configured to:
receive the first access key and the second access key from the peripheral circuitry;
compare the first access key with the second access key to determine whether the second access key corresponds to the first access key; and
determine whether to permit or prohibit execution of the access command at the fuse array based on comparing the first access key with the second access key.
6. The memory device of claim 5 , wherein the authentication component is configured to block the control signals from reaching the fuse array when the second access key is different from the first access key, the control signals comprising one or more addresses of fuses of the fuse array, a read command associated with the one or more addresses, a write command associated with the one or more addresses, or a combination thereof.
7. The memory device of claim 5 , wherein the authentication component is configured to disable a voltage source coupled with the fuse array and configured to generate a fuse programming voltage.
8. The memory device of claim 5 , wherein the authentication component is configured to disable the peripheral circuitry, wherein the peripheral circuitry is further configured to perform test mode functions different from generating the control signals for the fuse array.
9. The memory device of claim 5 , wherein the authentication component is configured to nullify the access command when the second access key is different from the first access key.
10. A method, comprising:
receiving a predetermined sequence of signals from a host device through a first set of pins of a memory device;
retrieving a first access key from a plurality of nonvolatile memory elements of the memory device in response to receiving the predetermined sequence of signals;
configuring a second set of pins of the memory device to output the first access key; and
transmitting the retrieved first access key to the host device using the second set of pins after configuring the second set of pins.
11. The method of claim 10 , wherein the second set of pins are designated for otherwise receiving inputs only from the host device.
12. The method of claim 10 , further comprising:
receiving an access command from the host device, the access command directed to a fuse array of the memory device and including a second access key; and
generating control signals for the fuse array in response to receiving the access command, the control signals including one or more addresses of fuses of the fuse array, a read command associated with the one or more addresses, a write command associated with the one or more addresses, or a combination thereof.
13. The method of claim 12 , further comprising:
comparing the first access key with the second access key to determine whether the second access key corresponds to the first access key; and
determining whether to permit or prohibit execution of the access command at the fuse array based on comparing the first access key with the second access key.
14. The method of claim 13 , wherein prohibiting the execution when the second access key is different from the first access key includes:
blocking the control signals from reaching the fuse array;
disabling a voltage source coupled with the fuse array and configured to generate a fuse programming voltage; or
disabling circuitry of the memory device configured to perform test mode functions different from generating the control signals for the fuse array.
15. A system, comprising:
a host device configured to:
transmit a predetermined sequence of signals through a first channel coupled with a memory device; and
monitor a second channel coupled with the memory device for a first access key sent from the memory device in response to receiving the predetermined sequence of signals;
wherein the memory device is configured to:
receive the predetermined sequence of signals through the first channel;
retrieve the first access key from a plurality of nonvolatile memory elements in response to receiving the predetermined sequence of signals;
configure one or more pins of the memory device to output the first access key, wherein the one or more pins are coupled with the second channel; and
transmit the first access key to the host device using the one or more pins.
16. The system of claim 15 , wherein the one or more pins of the memory device are designated for otherwise only receiving signals from the host device.
17. The system of claim 15 , wherein the predetermined sequence of signals corresponds to a predetermined sequence of two or more commands directed to the memory device.
18. The system of claim 15 , wherein the predetermined sequence of signals corresponds to a predetermined combination of two or more voltage levels as a function of time during a fixed duration.
19. The system of claim 15 , wherein the host device is further configured to:
receive the first access key sent from the memory device through the second channel; and
generate an access command directed to a fuse array of the memory device, the access command including the first access key.
20. The system of claim 15 , wherein the memory device is further configured to:
retrieve the first access key from the plurality of nonvolatile memory elements in response to receiving an access command from the host device directed to a fuse array of the memory device, wherein the access command includes a second access key;
compare the first access key with the second access key to determine whether the second access key corresponds to the first access key; and
determine whether to permit or prohibit execution of the access command at the fuse array based on comparing the first access key with the second access key.