NSA: Encryption Methods of The Past, Present and Future

Rachael Riggs

Henley-Putnam

National American University

NSA: Encryption Methods of The Past, Present and Future

When the National Security Agency was formed in 1952, the agency took over the responsibility for the U.S. government's encryption methods. The NSA handles the United States Signals Intelligence and Cryptanalysis. They are in the business of code-making and code-breaking. The details of many of the systems and methods used in the NSA are classified; however, they have helped to develop a few different encryption systems to be used by the public.

In 1977 the first federal encryption standard became that of the Data Encryption Standard or known as DES, which later became triple DES. As advancements in computers and technology progressed throughout the years, the small key size of DES became a security issue, and a new encryption method was sought to replace it.

In the year 2000 NIST selected the second federal encryption standard to be Advanced Encryption Standard or AES. The AES encryption is a mathematical algorithm that uses a symmetric key block cipher. It has been approved for type 1 use in some NSA systems. A Type 1 product is a system that is certified by the NSA for securing classified government information. The NSA also often uses AES in Type 3 products, which is a system for use with sensitive but unclassified information.

AES was chosen to replace the less secure Data Encryption Standard because of the security that the algorithm offers. DES has a 56-bit key, while AES allows the choice of 128-bit, 192-bit. Or 256-bit key making AES encryption a much stronger choice. AES works efficiently in both hardware and software and is much faster than the outdated DES. The rounds involved with AES are 10 rounds for 128-bit, 12 rounds for 192-bit, 14 rounds for 256-bit. Inside of each round of AES, there are four different stages. These stages include Subbytes, shift rows, Mix Columns, and Add round key. The encryption process involved in AES is the same as the decryption process. AES works on the Substitution and Permutation Principle. In AES the entire block is processed, while DES is divided into two halves before further processing. (Tech Differences, 2016) (Crypto Museum, 2019)

DES and AES are both symmetric. Symmetric standards require the sender and the receiver to share the same key. Asymmetric encryption uses two keys, a public key, and a private key. A public key is used to encrypt the contents of a message, and a recipient's private key (secret key) is then used to decrypt the message.

DES has a 56-bit key size. The smaller key size makes it less secure than AES, it is a block cipher algorithm, and the block is 64 bits. DES has 16 identical rounds. Before the main rounds, the block is divided into two 32-bit halves it begins its rounds of crisscrossing, known as the Feistel scheme. To decrypt this same structure is then done in the reverse order. The Feistel scheme consists of four stages: Expansion, key mixing, substitution, and permutation.

Brute force attacks are the most common method of attacks in penetrating an encryption method. AES has proven to withstand these attacks over that of DES. “Strong encryption makes data private, but not necessarily secure. To be secure, the recipient of the data, often a server, must be positively identified as being the approved party. This is usually accomplished online using digital signatures or certificates.” (Moore, 2005)

Further advancements in technology have brought the realization of needing to find Quantum Cryptography methods. Quantum Computers are capable of breaking the block ciphers and key encryptions of the past and also providing the utmost security of systems in the future with their ability to generate mass amounts of random numbers. Quantum Key distribution is already being used for many systems, but this is a key distribution and not a form of encryption. “QKD doesn’t actually encrypt user data but makes it possible for users to securely distribute keys to each other, which can then be used for subsequent encrypted communication.” (Cardinal, 2019) (kurzweilai, 2012)

A three-state quantum cryptography protocol called KAK has been developed to lead the way into quantum encryption. “In quantum computing, a qubit or quantum bit is a unit of quantum information — the quantum analogue of the classical bit. Unlike a classical bit which can take only the value of either 0 or 1, the state of a qubit can be in a 'superposition' of 0 and 1 simultaneously.” - Dr. Makarov (Kassner, 2012) The NSA is planning the transition into quantum-resistant algorithms as well as quantum digital signatures, and quantum fingerprinting. The future of quantum computers will provide new quantum cryptography, and a future of quantum computer inspired encryption methods that haven’t been seen yet.

The encryption method of AES is currently doing exactly what it was made to do, protect private data. But, anything that can be designed, has the ability to be broken. As more complex programs are created and larger more secure encryption standards are needed new methods will be crucial.

(Pathak, 2018) (Auburn, 2003) (Aditya) (Quantum Exchange, n.d.)

References

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Aditya, J. a. (n.d.). Quantum Cryptography. Retrieved from https://cs.stanford.edu/people/adityaj/QuantumCryptography.pdf

Auburn, B. (2003). Quantum Encryption - A Means to Perfect Security? Sans Institute. Retrieved from https://www.sans.org/reading-room/whitepapers/vpns/quantum-encryption-means-perfect-security-986

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Pathak, K. T. (2018, July 26). Kak’s three-stage protocol of secure quantum communication revisited: hitherto unknown strengths and weaknesses of the protocol. Quantum Information Processing(17), 229. doi:https://doi.org/10.1007/s11128-018-2001-z

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Tech Differences. (2016, October 20). Difference Between DES (Data Encryption Standard) and AES (Advanced Encryption Standard). Retrieved from Tech Differences: https://techdifferences.com/difference-between-des-and-aes.html

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