  A Machine-Critical Application is a system that is fundamentally necessary to
the success of specific and sensitive operations such as search and recovery,
rescue, military, and emergency management actions. Recent advances in Machine
Learning, Natural Language Processing, voice recognition, and speech processing
technologies have naturally allowed the development and deployment of
speech-based conversational interfaces to interact with various
machine-critical applications. While these conversational interfaces have
allowed users to give voice commands to carry out strategic and critical
activities, their robustness to adversarial attacks remains uncertain and
unclear. Indeed, Adversarial Artificial Intelligence (AI) which refers to a set
of techniques that attempt to fool machine learning models with deceptive data,
is a growing threat in the AI and machine learning research community, in
particular for machine-critical applications. The most common reason of
adversarial attacks is to cause a malfunction in a machine learning model. An
adversarial attack might entail presenting a model with inaccurate or
fabricated samples as it's training data, or introducing maliciously designed
data to deceive an already trained model. While focusing on speech recognition
for machine-critical applications, in this paper, we first review existing
speech recognition techniques, then, we investigate the effectiveness of
adversarial attacks and defenses against these systems, before outlining
research challenges, defense recommendations, and future work. This paper is
expected to serve researchers and practitioners as a reference to help them in
understanding the challenges, position themselves and, ultimately, help them to
improve existing models of speech recognition for mission-critical
applications. Keywords: Mission-Critical Applications, Adversarial AI, Speech
Recognition Systems.

Sound;Cryptography and Security;Machine Learning;Audio and Speech Processing