Key Points
- Encryption algorithms are mathematical procedures that convert readable data into ciphertext. Only the key holder can reverse the process.
- Symmetric encryption uses a single shared key for both encoding and decoding; AES is the dominant modern standard.
- Asymmetric encryption uses a public-private key pair, eliminating the need to share a secret in advance. RSA and ECC are the leading standards.
- Hashing algorithms produce a fixed-length digest for integrity verification, not confidentiality, with SHA-2 as the current standard.
- WPA3-Enterprise and 802.1X rely on these encryption algorithms to protect enterprise Wi-Fi authentication and data in transit.
Protecting data at rest, in transit, and in use all comes down to one question: which encryption algorithm is doing the work, and how strong is it? Choosing the wrong algorithm, or relying on an outdated standard, leaves organizations open to credential theft, data interception, and compliance failures.
This guide covers the major categories of encryption algorithms, the named standards IT teams encounter in practice, the role hashing plays alongside encryption, and what post-quantum developments mean for organizations planning ahead.
What Are Encryption Algorithms?
An encryption algorithm is a mathematical procedure that converts plaintext data into ciphertext using a key, making the data unreadable to anyone who does not hold the correct key for decryption.
Two primary properties define any encryption algorithm:
- Confidentiality: Only the key holder can read the encrypted data.
- Integrity: Some algorithms also detect whether data has been altered since it was encrypted.
The strength of an algorithm depends on its key length, the complexity of the mathematical operation, and whether known attacks can reduce the time required to break it. A 56-bit key can be exhaustively searched in hours with modern hardware; a 256-bit key cannot be feasibly brute-forced with any computing infrastructure that currently exists.
Symmetric Encryption Algorithms
Symmetric encryption uses a single secret key to both encrypt and decrypt data. Because the same key performs both operations, symmetric algorithms are fast and computationally efficient, making them the standard choice for encrypting large volumes of data.
The central challenge with symmetric encryption is key distribution: both parties must somehow share that secret key without exposing it to interception.
Advanced Encryption Standard (AES)
The advanced encryption standard (AES) is a Federal Information Processing Standard (FIPS)-approved symmetric block cipher. AES is based on the Rijndael algorithm, and works by encrypting and decrypting data in 128-bit blocks. It is defined in FIPS 197 and was published in November 2001 after a multi-year open competition to replace the Data Encryption Standard (DES).
AES is available in three key lengths: 128, 192, and 256 bits. AES-256 is the variant most commonly mandated for government and regulated-industry workloads. For a detailed technical breakdown, see our AES deep dive.
Data Encryption Standard and Triple DES
The Data Encryption Standard (DES) used a 56-bit key and is now considered cryptographically broken — its key space is small enough that a modern computer can exhaust it. Triple DES (3DES) extended the algorithm by applying DES three times with different keys, increasing effective key length, but it has since been deprecated by NIST due to vulnerability to practical attacks against its 64-bit block size.
Asymmetric Encryption Algorithms
Asymmetric encryption, also called public-key cryptography, uses two mathematically related keys: a public key shared openly and a private key held only by the owner. Data encrypted with the public key can only be decrypted with the corresponding private key, and vice versa.
This design solves the key-distribution problem of symmetric encryption. Two parties can exchange their public keys over an untrusted channel, establish a shared secret, and then use a faster symmetric cipher for the actual data. That handshake pattern underlies Transport Layer Security (TLS), which secures nearly all HTTPS traffic on the web.
RSA
RSA, named for its inventors Rivest, Shamir, and Adleman, is the most widely deployed asymmetric algorithm. Its security depends on the computational difficulty of factoring the product of two large prime numbers. The current specifications are published in RFC 8017 (PKCS #1 v2.2), which covers both encryption and digital signature schemes.
RSA keys are typically 2048 or 4096 bits. The larger the key, the harder the algorithm is to break, but also the more processing power it requires per operation.
Elliptic Curve Cryptography (ECC)
Elliptic curve cryptography (ECC) is an asymmetric approach that derives its security from the mathematics of elliptic curves over finite fields rather than integer factoring. The practical benefit is that ECC achieves equivalent security to RSA with far smaller keys: a 256-bit ECC key provides roughly the same protection as a 3,072-bit RSA key.
NIST has standardized several ECC curves, including P-256, P-384, and P-521. Smaller key sizes make ECC particularly attractive for mobile devices, internet of things (IoT) hardware, and TLS certificates, where processing overhead and bandwidth matter.
How Encryption Works: Symmetric vs. Asymmetric at a Glance
Most real-world protocols combine both encryption algorithms in a hybrid model. TLS, for example, uses asymmetric cryptography to authenticate the server and exchange a session key, then switches to AES for the bulk data transfer. This hybrid approach gives the security of public-key authentication and the speed of symmetric encryption.
| Property | Symmetric Encryption | Asymmetric Encryption |
| Keys used | One shared secret key | Public key + private key pair |
| Speed | Fast, suited for bulk data | Slower, suited for key exchange |
| Key distribution challenge | High: secret must be shared securely | Low: public key can be shared openly |
| Common algorithms | AES, 3DES (deprecated) | RSA, ECC |
| Typical use | File encryption, disk encryption, VPN data | TLS handshakes, digital signatures, certificates |
Hashing Algorithms: Integrity Without Encryption
Hashing is often grouped with encryption algorithms but serves a different purpose. A hash function takes input data of any length and produces a fixed-length output called a digest. The process is one-way. There is no key and no decryption step. Hashing verifies that data has not changed, rather than concealing it.
The SHA-2 family, specified in FIPS 180-4, is the current standard for secure hashing. SHA-256 and SHA-384 are the variants most commonly seen in TLS certificates, code-signing workflows, and password storage systems.
Hash functions are a core component of digital signatures: the sender hashes a message, encrypts that hash with their private key, and sends both the message and the encrypted hash. The recipient decrypts the hash and recomputes it from the received message; if the two values match, the message is authentic and unaltered.
Encryption Algorithms in Wi-Fi and Network Access
One topic that deserves more discussion is how these algorithms operate at the network access layer, where the choice of algorithm directly determines whether enterprise Wi-Fi is secure or vulnerable to interception.
WPA2 and WPA3: AES in Practice
Wi-Fi Protected Access 2 (WPA2) uses AES in Counter Mode with CBC-MAC (CCMP) for data encryption. WPA3, the successor standard, uses AES-based GCMP (Galois/Counter Mode Protocol), with WPA3-Enterprise’s highest security mode mandating 256-bit GCMP encryption.
WPA3-Personal, meanwhile, replaces the pre-shared key (PSK) handshake with Simultaneous Authentication of Equals (SAE), which resists offline dictionary attacks that could compromise WPA2-Personal networks where the underlying passphrase is weak.
802.1X and TLS: Asymmetric Cryptography at the Network Edge
Enterprise Wi-Fi authentication via 802.1X uses the Extensible Authentication Protocol (EAP), with the most secure variant (EAP-TLS) establishing a full TLS tunnel between the client device and the authentication server before any access is granted. That TLS handshake relies directly on RSA or ECC certificates to authenticate both endpoints.
The practical implication: organizations running certificate-based 802.1X authentication are already deploying asymmetric encryption at the network edge. Every device certificate issued by a certificate authority (CA) carries an RSA or ECC public key, and the corresponding private key never leaves the device. This is what makes EAP-TLS resistant to credential theft. There is no reusable password to intercept or replay.
Post-Quantum Cryptography: What Comes Next
Quantum computers capable of running Shor’s algorithm at scale would break both RSA and ECC by solving the underlying math problems in polynomial time. That threat is not immediate, but cryptographic migrations take years, which is why NIST finalized its first three post-quantum cryptography (PQC) standards in August 2024.
The three standards are:
- FIPS 203 (ML-KEM): A module-lattice-based key encapsulation mechanism, replacing asymmetric key exchange.
- FIPS 204 (ML-DSA): A module-lattice-based digital signature algorithm, replacing RSA and ECC signatures.
- FIPS 205 (SLH-DSA): A stateless hash-based digital signature algorithm serving as a backup signature scheme.
AES-256 and SHA-2 remain secure against quantum attack. The migration work centers on replacing RSA and ECC in public-key infrastructure (PKI), TLS, and key exchange protocols.
Strengthen Your Network With Certificate-Based Encryption
Understanding encryption algorithms is the foundation. Deploying them correctly across enterprise Wi-Fi, VPN, and application access is where most organizations run into complexity.
JoinNow Dynamic PKI manages the full lifecycle of RSA and ECC certificates (issuance, renewal, and revocation) without requiring on-premises hardware. When a device authenticates to the network, its certificate carries a cryptographic identity tied to the user and device, enforced by the PKI. When a device is decommissioned or a user is offboarded, the certificate is revoked and access is immediately blocked.
JoinNow Cloud RADIUS works alongside the PKI to enforce EAP-TLS authentication for WPA2-Enterprise and WPA3-Enterprise networks. Every authentication attempt triggers a real-time identity lookup against your identity provider (IdP), so only current, compliant devices gain access — regardless of which encryption algorithm the RADIUS exchange uses under the hood.
If your organization is evaluating a move to certificate-based Wi-Fi authentication or planning a PKI migration ahead of post-quantum requirements, schedule a demo to see how SecureW2 deploys in hours rather than months.
Frequently Asked Questions
What is the difference between symmetric and asymmetric encryption?
Symmetric encryption uses one shared secret key for both encrypting and decrypting data, making it fast but requiring a secure method to share that key between parties. Asymmetric encryption uses a mathematically linked key pair (a public key that anyone can see and a private key the owner keeps secret), so data encrypted with the public key can only be decrypted with the corresponding private key. Most modern protocols combine both: asymmetric cryptography handles the initial key exchange, and symmetric encryption handles the actual data transfer.
Which encryption algorithm is the strongest?
AES-256 is the most widely trusted symmetric encryption algorithm for protecting data at rest and in transit, and no practical attack against it exists with current computing technology. For asymmetric operations, ECC with a 384-bit key or RSA with a 4,096-bit key are considered strong today, though both will require replacement as quantum computing matures. The NIST post-quantum standards (ML-KEM, ML-DSA, and SLH-DSA) are the designated successors for asymmetric key exchange and digital signatures.
What are the 4 types of encryption algorithms?
Encryption algorithms are commonly grouped into four categories: symmetric block ciphers (such as AES), symmetric stream ciphers (such as ChaCha20), asymmetric algorithms (such as RSA and ECC), and hash functions (such as SHA-256). Block ciphers operate on fixed-size data blocks; stream ciphers encrypt data one bit or byte at a time. Hash functions are technically a separate category because they are one-way — they verify integrity rather than providing confidential communication.
How does encryption apply to Wi-Fi security?
Wi-Fi security relies directly on encryption algorithms at two layers. The data layer uses AES-CCMP in WPA2 or AES-GCMP in WPA3 to encrypt every packet transmitted over the air. The authentication layer in enterprise networks uses 802.1X with EAP protocols — the most secure of which, EAP-TLS, establishes a TLS tunnel using RSA or ECC certificates before granting any access. Certificate-based Wi-Fi authentication is the primary defense against credential theft on enterprise wireless networks.
What is a hashing algorithm and how does it differ from encryption?
A hashing algorithm takes any input and produces a fixed-length digest — SHA-256 always outputs a 256-bit value regardless of whether the input is one word or one terabyte. Unlike encryption, hashing is a one-way operation: there is no key and no way to reverse the digest back to the original data. Hashes are used to verify file integrity, store passwords securely, and create the digital signature fingerprint that proves a message or certificate has not been tampered with.
