In the context of asymmetric cryptography, McLuhan’s figure and ground concept can be applied to explore both the explicit function and the underlying influence of this cryptographic system on security, trust, and digital communication.

Figure: The Encryption and Decryption Process

The figure in asymmetric cryptography is the primary function—the encryption and decryption process using pairs of public and private keys. This process is the part that most people focus on and understand directly:

• Encryption and Decryption: With asymmetric cryptography, data is encrypted with a recipient’s public key and can only be decrypted by their corresponding private key. This core process ensures data confidentiality, integrity, and authentication in digital communication.
• Key Pair Concept: The use of a unique public-private key pair is the main focus of the cryptographic system, allowing for secure exchanges between parties who may never have met or previously exchanged information.

People generally think of this figure as the main “message” or function of asymmetric cryptography: a way to secure information in transit and verify identities.

Ground: The Infrastructure, Trust Model, and Social Impact

The ground in asymmetric cryptography is the vast environment of technological, social, and trust-related contexts that make the encryption process functional, reliable, and impactful. While often overlooked, these background elements are crucial to how asymmetric cryptography shapes digital society:

• Public Key Infrastructure (PKI): This infrastructure provides the certification authorities (CAs) and the systems required to manage, distribute, and validate public keys, creating a trusted environment where individuals and organizations can rely on one another’s digital identities.
• Trust Model and Certificate Authorities: The trust model and CAs are essential to ensuring that a public key genuinely belongs to its claimed owner. However, this ground is often hidden, and users take it for granted without realizing that the model is built on centralized trust and potential vulnerabilities (such as CA breaches).
• Legal and Regulatory Environment: Governments and regulatory frameworks impact how cryptography is used, such as export controls, compliance with standards (e.g., GDPR for data privacy), and legal recognition of digital signatures.
• Social and Cultural Impact on Privacy: Asymmetric cryptography, as part of the ground, influences our broader expectations around privacy, trust, and security in digital interactions, even if we’re not directly thinking about it. The assurance provided by this cryptography underpins our trust in online transactions, financial exchanges, and personal communications.

In this way, the ground includes the extensive network of trust, legal structures, and social expectations that support the functionality of asymmetric cryptography, even if it isn’t directly visible in the encryption/decryption action.

Figure-Ground Reversal

A figure-ground reversal could occur when the background elements of asymmetric cryptography—the infrastructure, regulatory frameworks, or vulnerabilities—suddenly come to the foreground. For example:

• If a Certificate Authority is compromised, people might shift their focus to the weaknesses in the PKI trust model (previously in the ground), questioning the reliability of the entire system.
• Debates around governmental backdoors or encryption standards can bring the regulatory environment into focus, revealing potential limitations and risks to privacy within the cryptographic system.

In Summary

• Figure: The visible encryption/decryption process using public and private keys.
• Ground: The underlying infrastructure, trust systems, legal frameworks, and cultural expectations that support and shape how asymmetric cryptography operates in society.

Understanding asymmetric cryptography fully requires recognizing both its technical function (figure) and the extensive, often hidden context (ground) that sustains its role in securing digital communication and building trust in the digital age.