Methods and systems for access control

1. A method of controlling access to an access-controlled point, comprising:

generating a random string or pseudorandom string;

acoustically broadcasting a beacon message comprising the random string or pseudorandom string;

acoustically receiving, in response to acoustically broadcasting the beacon message, an authentication message comprising a user identification and an authentication string;

obtaining a password associated with the user identification;

computing a verification string using the password and the random string or pseudorandom string;

verifying the authentication string in the authentication message using the verification string; and

transmitting, in response to successfully verifying the authentication string in the authentication message, an unlocking message to the access controlled point to unlock the access controlled point.

2. The method of claim 1 , further comprising, prior to broadcasting the beacon message, acoustically modulating the beacon message.

3. The method of claim 2 , wherein the acoustically modulating comprises frequency modulating the beacon message or amplitude modulating the beacon message.

4. The method of claim 1 , further comprising acoustically demodulating the authentication message.

5. The method of claim 4 , wherein the demodulating comprises frequency demodulating the authentication message or amplitude demodulating the authentication message.

6. The method of claim 1 , wherein the verifying comprises: comparing the authentication string to the verification string to determine whether the authentication string is identical to the verification string.

7. The method of claim 1 , wherein the computing comprises performing a hash function on the password and the random string or pseudorandom string to generate the verification string.

8. An access control device, comprising:

a microphone configured to receive audio input;

a speaker configured to emit audio output;

a memory comprising instructions; and

a processor communicatively coupled with the memory, the processor being configured to execute the instructions to:

generate a random string or pseudorandom string;

cause the speaker to acoustically broadcast a beacon message comprising the random string or pseudorandom string;

cause the microphone to acoustically receive, in response to acoustically broadcasting the beacon message, an authentication message comprising a user identification and an authentication string;

obtain a password associated with the user identification;

compute a verification string using the password and the random string or pseudorandom string;

verify the authentication string in the authentication message using the verification string; and

transmit, in response to successfully verifying the authentication string in the authentication message, an unlocking message to an access controlled point to unlock the access controlled point.

9. The access control device of claim 8 , wherein the processor is further configured to, prior to broadcasting the beacon message, acoustically modulate the beacon message.

10. The access control device of claim 9 , wherein the acoustically modulating comprises frequency modulating the beacon message or amplitude modulating the beacon message.

11. The access control device of claim 8 , wherein the processor is further configured to acoustically demodulate the authentication message.

12. The access control device of claim 11 , wherein the demodulating comprises frequency demodulating the authentication message or amplitude demodulating the authentication message.

13. The access control device of claim 8 , wherein the verifying comprises comparing the authentication string to the verification string to determine whether the authentication string is identical to the verification string.

14. The access control device of claim 8 , wherein the computing comprises performing a hash function on the password and the random string or pseudorandom string to generate the verification string.

15. A non-transitory computer readable medium comprising instructions that, when executed by a processor, cause the processor to:

generate a random string or pseudorandom string;

cause a speaker to acoustically broadcast a beacon message comprising the random string or pseudorandom string;

cause a microphone to acoustically receive, in response to acoustically broadcasting the beacon message, an authentication message comprising a user identification and an authentication string;

obtain a password associated with the user identification;

compute a verification string using the password and the random string or pseudorandom string;

verify the authentication string in the authentication message using the verification string; and

transmit, in response to successfully verifying the authentication string in the authentication message, an unlocking message to an access controlled point to unlock the access controlled point.

16. The non-transitory computer readable medium of claim 15 , further comprises instructions that, when executed by the processor, cause the processor, prior to broadcasting the beacon message, acoustically modulate the beacon message.

17. The non-transitory computer readable medium of claim 16 , wherein the acoustically modulating comprises frequency modulating the beacon message or amplitude modulating the beacon message.

18. The non-transitory computer readable medium of claim 15 , further comprises instructions that, when executed by the processor, cause the processor to acoustically demodulate the authentication message.

19. The non-transitory computer readable medium of claim 18 , wherein the demodulating comprises frequency demodulating the authentication message or amplitude demodulating the authentication message.

20. The non-transitory computer readable medium of claim 15 , wherein the instructions for computing further comprises instructions that, when executed by the processor, cause the processor to perform a hash function on the password and the random string or pseudorandom string to generate the verification string.