storing passwords in soundwaves
I built this 8 months ago when I had a DSP course in my semester.
GitHub link: https://github.com/stackbuffer/ads
Here's how it works for nerds:
Input data is converted into binary form, then based on the type of bit, whether it is a zero bit or one bit, a wave file is generated.
For 0, the frequency of sound is 1200 Hz and for 1, the frequency of sound is 2400 Hz. Each of these sounds or tones plays for 10 milliseconds.
The entire binary data makes up a wave file that contains the input information.
This information can be extracted by slicing the wave file into 10-millisecond chunks. On each chunk perform Fast Fourier Transform and extract the peak or dominant frequency. If the frequency is equal to 1200 Hz, then it is a zero bit and if it is 2400 Hz, then it is one bit. These bits can be combined to form the original input data.
Note: This only works because the data is being used on the same PC, if you want to transmit the sound over FM or AM or some kind of other methods, then do not use 1200 Hz and 2400 Hz, these two are harmonic frequencies and will mess up the message signal.