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Symmetric Encryption Algorithm: Is It Reliable Enough?

Symmetric Encryption Algorithm: Is It Reliable Enough?

 By Charles Joseph | Cybersecurity Researcher
 Published on August 1st, 2023
This post was updated on November 25th, 2023

Symmetric encryption algorithm is a type of encryption where a single key is used for both the encryption and decryption of data. This means the sender and receiver use the same secret key to respectively encrypt and decrypt the information being sent. It’s often used when large amounts of data need to be encrypted due to its efficiency and speed.

Symmetric Encryption Algorithm Examples

1. Secure Socket Layer (SSL)

Secure Socket Layer, more commonly referred to as SSL, is a protocol used for web security. It’s especially prevalent in the handling of sensitive information such as credit card numbers, personal details, and passwords. SSL uses symmetric encryption as part of its process to ensure the safety of the data being transferred.

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Whenever you access a secure website, let’s say your online banking portal or ecommerce site, the presence of SSL is usually indicated by a small lock icon in the address bar of your web browser. This is your assurance that the data you send and receive from the site is protected from potential prying eyes.

While SSL employs asymmetric encryption for the initial key exchange, it uses symmetric encryption for the actual data transfer. This is because symmetric encryption, like that in the SSL protocol, is faster and more efficient, particularly when dealing with large amounts of data.

2. Advanced Encryption Standard (AES)

Advanced Encryption Standard, or AES, is a widely used symmetric encryption algorithm across many sectors. Replacing the older Data Encryption Standard (DES), AES was established as a standard by the U.S. National Institute of Standards and Technology (NIST) in 2001.

AES offers high-level security and is favored for its efficiency and speed, particularly when encrypting large volumes of data. It operates on block cipher method, which divides data into blocks and then encrypts each block using the same key. The standard key sizes are 128, 192, and 256 bits.

AES is considered to be virtually unbreakable with current technology when used properly. For this reason, it’s trusted for securing sensitive information in many fields, including government, financial services, and healthcare.

3. Data Encryption Standard (DES)

Data Encryption Standard, known as DES, is a symmetric encryption method that was widely used for many years. Developed in the 1970s by IBM and the U.S. government, DES was one of the first encryption algorithms to be made public.

DES operates by dividing data into blocks and then encrypting or decrypting each block with the same key. The standard key size for DES is 56 bits. Although this was considered secure when DES was created, advancements in computing power have made DES less safe over time.

While DES isn’t as secure as newer algorithms such as AES, it serves as a valuable example of symmetric encryption and its principles. Despite its decreased security, many legacy systems continue to use DES, especially where the data isn’t highly sensitive.


In summary, symmetric encryption algorithms provide an efficient and secure means of transmitting data between two parties. Examples such as SSL, AES, and DES highlight the importance and functionality of symmetric algorithms in various areas, enhancing data security in our ever-growing digital world.

Key Takeaways

  • Symmetric encryption algorithms use a single key for both encrypting and decrypting data, making them efficient and quick, especially for large volumes of data.
  • Secure Socket Layer (SSL) uses symmetric encryption as part of its process to secure communication across the Internet.
  • Advanced Encryption Standard (AES) is a predominant encryption method, adopted by the U.S. government and used worldwide, considered virtually unbreakable with current technology.
  • Data Encryption Standard (DES), while less secure due to advances in processing power, remains in use in some legacy systems and serves as an essential case study regarding symmetric encryption methods.
  • Symmetric encryption algorithms are a foundational piece of cybersecurity and are instrumental in protecting data across various sectors, including government, financial services, and healthcare.
  • Related Questions

    1. What are the pros and cons of symmetric encryption algorithms?

    Symmetric encryption algorithms are efficient and fast, particularly for large amounts of data. However, the major drawback is key distribution – the same key must securely reach all communication parties, which can be challenging and potentially risky.

    2. Why does SSL use symmetric encryption even though it’s used over public networks?

    SSL uses a combination of asymmetric and symmetric encryption. Asymmetric encryption is used for the initial key exchange because it’s secure over public networks. Once a secure connection is established, the actual data transfer uses the faster and more efficient symmetric encryption.

    3. How does AES differ from DES?

    AES and DES are both symmetric encryption algorithms, but AES is considered more secure due to its longer key lengths – 128, 192, and 256 bits versus DES’s 56 bits. The computational power required to break AES encryption makes it virtually unbreakable with current technology.

    4. Why has DES fallen out of favor?

    DES has become less secure over time due to advances in technology and computing power. While it was considered secure when it was created in the 1970s, today’s computers can break a DES key in a reasonable amount of time, leading to its replacement with more secure options like AES.

    5. Are symmetric encryption algorithms still relevant with the emergence of quantum computing?

    While quantum computing presents challenges to cryptographic security, symmetric cryptography, in particular, remains more resistant than its asymmetric counterpart. However, the key length may need to be increased for additional security in a quantum context.

    "Amateurs hack systems, professionals hack people."
    -- Bruce Schneier, a renown computer security professional
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