Audio Captcha

Unlock security with Audio CAPTCHA aastery.

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Usage

Generating audio CAPTCHA with the AudioCaptcha` class is remarkably simple.

from captcha.audio import AudioCaptcha

captcha = AudioCaptcha()
data: bytearray = captcha.generate('1234')

Here is an example of an audio captcha:

Voice library

The AudioCaptcha module comes with built-in voice files for numbers from 0 to 9. However, for enhanced security and customization, it is highly recommended to use your own voice library. This section will guide you on how to generate your own voice library using espeak and ffmpeg.

# Set the language code
export ESLANG=en

# Create a directory for the specified language code
mkdir "$ESLANG"

# Loop through each character (a-z, A-Z, 0-9) and create a directory for each
for i in {a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,0,1,2,3,4,5,6,7,8,9}; do
    mkdir "$ESLANG/$i"
    espeak -a 150 -s 100 -p 15 -v "$ESLANG" "$i" -w "$ESLANG/$i/orig_default.wav"
    ffmpeg -i "$ESLANG/$i/orig_default.wav" -ar 8000 -ac 1 -acodec pcm_u8 "$ESLANG/$i/default.wav"
    rm "$ESLANG/$i/orig_default.wav"
done

Then use the voice library:

from captcha.audio import AudioCaptcha

voice_dir = "path/to/en"  # we generated the wav files in "en" folder
captcha = AudioCaptcha(voice_dir)

Web server

In addition to generating and saving the voice files in a directory or cloud storage like Amazon S3, you can also serve the Voice CAPTCHA audio files on-the-fly.

Let’s explore how to use the CAPTCHA library to dynamically serve audio CAPTCHAs within a Flask application.

from io import BytesIO
from flask import Flask, Response
from captcha.audio import AudioCaptcha

audio = AudioCaptcha()
app = Flask(__name__)


@app.route("/captcha")
def captcha_view():
    # add your own logic to generate the code
    code = "1234"
    data = audio.generate(code)
    return Response(BytesIO(data), mimetype="audio/wav")