How to create cloudfront signed URL from mobile app?

There are several ways to do this here is one.

To create a signed URL for an Amazon S3 object in Python, you can use the boto3 library and the client.generate_presigned_url() method. This method allows you to create a URL that you can share with others that provides temporary access to download or upload an object in your bucket.

Here is an example of how you can use generate_presigned_url() to create a signed URL that allows a user to download an object from your bucket: (If you used this code as a lambda function or with secrets manager you would not need to embed credentials)

import boto3

# Replace ACCESS_KEY and SECRET_KEY with your Amazon S3 access key and secret key
s3 = boto3.client('s3', aws_access_key_id=ACCESS_KEY, aws_secret_access_key=SECRET_KEY)

# Replace BUCKET_NAME and OBJECT_KEY with the name of your bucket and the key of the object you want to create a signed URL for
url = s3.generate_presigned_url(
    ClientMethod='get_object',
    Params={
        'Bucket': BUCKET_NAME,
        'Key': OBJECT_KEY
    }
)

print(url)

If you need help generating code for most languages I suggest using CodeWhisperer, which is in free preview. https://aws.amazon.com/codewhisperer/