Since this seems to be a 2013 paper, does any one know whether there has been any update regarding software (except for GPG) or hardware defense against this attack?
Security
Confidentiality Integrity Availability
The researchers say in the FAQ that they disclosed it to GnuPG and they have mitigated their implementation against their specific attack, but it leaves the question of whether it is still vulrnable to a a more advanced method of audio sidechanneling and whether other encryption implementations, say, OpenSSL, OpenSSH, or Veracrypt, are also vulrnable to similar attacks.
This paper is a bullshit. Authors claim they are able to extract an RSA 4096 decryption key within an hour using a prepared cyphertext, but this cannot work for PGP. PGP uses an asymmetric cypher (i.e. RSA) only to encrypt a symmetric cypher key (e.g. AES) that is used to encrypt/decrypt the text itself. So RSA does not work for hours, it takes only few milliseconds to decrypt a key that is 256 bit maximum.
Even if this method worked, it would be very hardware dependant. They would need to tune their algorithm for each laptop being attacked. So if you don't give your laptop to attacker for several weeks, he won't be able to steal your key.
I don't know that much about audio sidechannels so I don't know how realistic this would be, but my immediate thought is whether this can be extended to extract not just a single key but other data as well. For example, if you had a phone next to a computer that was reading and displaying a text file that contained confidential information, or perhaps reading values from a database, could it be possible to leak the actual data this way?
I also wonder how many videos and audio recordings made near computers have encryption keys and other sensitive data hidden in them, just waiting to be decoded. Or whether a video recorded by a smartphone can reveal what the phone is doing in the background. A terrifying prospect.