Encryption Authority - Data Encryption Reference

Data encryption is one of the most consequential technical controls in modern cybersecurity, governing how sensitive information is protected at rest, in transit, and during processing. This page defines encryption, maps its major variants, explains how cryptographic mechanisms function in practice, and identifies the decision boundaries that determine which approach applies to a given context. Regulatory frameworks from the National Institute of Standards and Technology (NIST), the Health Insurance Portability and Accountability Act (HIPAA), and the Payment Card Industry Data Security Standard (PCI DSS) all impose specific encryption requirements, making this a compliance-critical domain across industries. The Encryption Authority hub coordinates reference coverage across the full network of member resources documented below.

Definition and Scope

Encryption is the process of transforming plaintext data into ciphertext using a cryptographic algorithm and key, such that only an authorized party holding the correct decryption key can recover the original information. NIST defines encryption formally in NIST SP 800-175B Rev 1, Guideline for Using Cryptographic Standards in the Federal Government, which also establishes approved algorithm families for federal information systems.

The scope of encryption spans three states of data:

1. Data at rest — stored data on disks, databases, or backup media
2. Data in transit — data moving across networks, including TLS-protected web sessions
3. Data in use — an emerging area addressed by confidential computing and homomorphic encryption

Encryption is classified by its key architecture into two primary families:

• Symmetric encryption: A single key encrypts and decrypts data. AES-256 is the dominant standard, approved under FIPS 197 (Advanced Encryption Standard). AES-256 uses a 256-bit key, making brute-force attacks computationally infeasible with current hardware.
• Asymmetric encryption: A mathematically linked key pair (public and private) is used. RSA and Elliptic Curve Cryptography (ECC) are the principal algorithms. RSA-2048 is the minimum key length recommended by NIST for asymmetric systems through 2030 (NIST SP 800-57 Part 1 Rev 5).

For readers building foundational understanding, the cybersecurity terminology and definitions page provides precise definitions for terms like ciphertext, key derivation, and certificate authority that underpin this discussion.

Data Security Authority covers the broader data protection landscape, including classification, access control, and retention frameworks that work alongside encryption.

Digital Security Authority addresses the intersection of encryption with digital identity systems and certificate management across enterprise environments.

How It Works

A cryptographic operation follows a defined sequence regardless of the algorithm family:

1. Key generation — A cryptographically secure random number generator produces a key of the required bit length.
2. Algorithm selection — The algorithm (e.g., AES-GCM, RSA-OAEP, ChaCha20-Poly1305) is chosen based on use case, performance requirements, and compliance mandates.
3. Encryption — The plaintext input is processed through the algorithm using the key, producing ciphertext and, in authenticated encryption modes, an authentication tag.
4. Key distribution — In asymmetric systems, the public key is shared openly; in symmetric systems, a key exchange protocol such as Diffie-Hellman or TLS handshake distributes the session key securely.
5. Decryption — The authorized recipient applies the correct key to the ciphertext using the same algorithm, recovering plaintext.
6. Key management — Keys are rotated, stored in hardware security modules (HSMs) or key management services (KMS), and revoked when compromised.

NIST SP 800-57 Part 1 specifies key management lifecycle requirements. The Federal Information Processing Standard FIPS 140-3 governs validation requirements for cryptographic modules used in federal systems, with four security levels ranging from Level 1 (basic software) to Level 4 (physical tamper resistance).

The conceptual relationship between encryption and broader security architecture is mapped in the how cybersecurity works conceptual overview, which situates cryptographic controls within the defense-in-depth model.

Cloud Security Authority covers encryption-in-transit and at-rest controls specific to cloud infrastructure, including provider-managed versus customer-managed key models.

Cloud Defense Authority addresses encryption's role within cloud threat mitigation strategies, including data exfiltration scenarios where encryption acts as a last line of defense.

Information Security Authority documents how encryption integrates with information security management systems (ISMS) and ISO/IEC 27001 control objectives.

Advanced Security Authority examines post-quantum cryptography (PQC) algorithm candidates standardized by NIST in 2024, including CRYSTALS-Kyber for key encapsulation and CRYSTALS-Dilithium for digital signatures (NIST IR 8413).

Common Scenarios

Encryption appears across a wide range of operational contexts. The following scenarios represent the highest-frequency deployment patterns documented in regulatory guidance and industry standards.

Healthcare: HIPAA-covered entities must encrypt electronic protected health information (ePHI) when transmitted over open networks, per the HIPAA Security Rule (45 CFR § 164.312(e)(2)(ii)). Encryption of ePHI at rest is an addressable implementation specification, meaning covered entities must implement it or document an equivalent alternative.

Payment systems: PCI DSS v4.0 (published by the PCI Security Standards Council) requires strong cryptography for cardholder data in transit across public networks and mandates AES-128 or higher for data at rest under Requirement 3.5.

State-level regulations: California's Consumer Privacy Act (CCPA) and the California Privacy Rights Act (CPRA) treat encryption as a mitigating factor in breach liability determinations. California Security Authority documents the state-specific regulatory stack, including the California IoT Security Law (SB-327) and its implications for device-level encryption.

Florida Security Authority covers Florida's data breach notification law (§ 501.171, Florida Statutes), which exempts encrypted data from notification triggers when keys remain uncompromised — a direct regulatory incentive for encryption adoption.

New York Security Authority addresses the New York SHIELD Act and the Department of Financial Services Cybersecurity Regulation (23 NYCRR Part 500), which mandates encryption of nonpublic information both in transit and at rest for regulated entities.

Texas Security Authority tracks the Texas Identity Theft Enforcement and Protection Act and Texas Business & Commerce Code § 521, which use encryption status as a threshold condition for breach notification requirements.

Email and endpoint encryption: Transport Layer Security (TLS) 1.3, finalized in RFC 8446, is the current standard for encrypting email in transit. S/MIME and PGP address end-to-end email encryption at the message level. Full-disk encryption via BitLocker (Windows) or FileVault (macOS) protects data at rest on endpoints.

Endpoint Security Authority covers full-disk encryption deployment, TPM integration for key storage, and pre-boot authentication policies across enterprise endpoint fleets.

Mobile Security Authority documents mobile device encryption standards, including iOS and Android hardware-backed encryption, and MDM policy enforcement for encryption compliance.

Network Security Authority addresses network-layer encryption, including IPsec VPN configurations, TLS certificate management, and encrypted DNS protocols (DoH, DoT).

Server Security Authority covers server-side encryption configuration hardening, including cipher suite selection, TLS protocol version enforcement, and certificate rotation procedures.

Application Security Authority examines application-layer encryption patterns, including encrypted field storage in databases, tokenization versus encryption for PCI-scoped data, and secrets management in CI/CD pipelines.

Ransomware interaction: Ransomware actors deploy their own encryption (typically AES-256 with RSA-wrapped keys) against victim data. Defenders' pre-existing encryption of backups and data stores does not prevent ransomware encryption of live files but does protect offline backup copies from exfiltration-based extortion.

Ransomware Authority provides a technical breakdown of ransomware encryption mechanics and the role of immutable, encrypted backups in recovery scenarios.

Cloud Backup Authority covers encrypted cloud backup architectures, including server-side versus client-side encryption models and key ownership implications for recovery.

Data Recovery Authority addresses scenarios where encryption complicates data recovery, including lost-key scenarios and forensic recovery from encrypted volumes.

Decision Boundaries

Choosing the appropriate encryption approach requires evaluating five discrete dimensions:

**1. Symmetric vs. Asym

For related coverage on this site: Regulatory Context for Cybersecurity.

References

• NIST SP 800-175B Rev. 1 – Guideline for Using Cryptographic Standards in the Federal Government
• FIPS 197 – Advanced Encryption Standard (AES)
• NIST SP 800-57 Part 1 Rev. 5 – Recommendation for Key Management
• NIST Computer Security Resource Center (CSRC) – Cryptographic Standards and Guidelines
• HHS – HIPAA Security Rule: Technical Safeguards (45 CFR § 164.312)
• 45 CFR Part 164 – Security and Privacy (HIPAA Security Rule), eCFR
• NIST SP 800-111 – Guide to Storage Encryption Technologies for End User Devices
• NIST SP 800-52 Rev. 2 – Guidelines for the Selection, Configuration, and Use of TLS Implementations
• NIST Post-Quantum Cryptography Standardization Project
• FTC – Protecting Personal Information: A Guide for Business