Page 33 – Encryption Consulting

Introduction to the Encryption Algorithm

Encryption serves as a method to conceal information by transforming it in a manner that gives the appearance of random data. Its significance lies in being a fundamental tool for ensuring security across the vast Internet landscape.

What is Encryption Algorithm?

To simplify, an encryption algorithm is like a secret code that makes information unreadable to people who shouldn’t see it. It uses special math rules and keys to jumble up data; only those with the right key can unscramble and understand the information. This is important for keeping our messages, passwords, and other sensitive data safe when we send them online or store them on our devices. It’s like locking our digital information to keep it private and secure.

There are two main types of encryption algorithms (Read more about them in the Encryption Basics Section):

Symmetric Encryption Algorithms

In symmetric encryption, a single key is used for encryption and decryption. The same key is shared between the communicating parties. While symmetric encryption is efficient, it requires a secure method for key exchange.
Asymmetric Encryption Algorithms

Asymmetric encryption, also known as public-key cryptography, uses a pair of keys: a public key for encryption and a private key for decryption. The public key can be freely distributed, allowing anyone to encrypt data, but only the private key holder can decrypt and access the original information.

How does the Encryption Algorithm work?

Encryption transforms readable “plaintext” into encoded “ciphertext” through cryptographic algorithms and mathematical models for secure data manipulation. Reverting this encoded data to its original form (plaintext) requires a decryption key—a series of numbers or a password, also generated through an algorithm.

Strong encryption practices involve using a vast array of cryptographic keys, making it practically impossible for unauthorized individuals to guess the correct key or employ brute force attacks to try every potential combination systematically. This complexity enhances the security of encrypted data.

An example of a basic encryption method is the “Caesar cipher,” attributed to Julius Caesar. In this substitution cipher, each letter is replaced by another letter positioned a fixed number of spaces down the alphabet. To decipher the message, the recipient needs the key—knowing, for instance, the specific shift applied (e.g., a “left shift four”). This means every “E” in the message would correspond to a “Y”.

How can encryption be used to protect data throughout its lifecycle?

The following refers to different states of data based on its activity or location within a computing environment:

Data-at-Rest

Stored or archived information that is not actively being used or transmitted. This data is typically saved on storage devices such as hard drives, solid-state drives, or other long-term storage solutions. Examples include files stored on your computer’s hard drive, data on a USB flash drive, and information saved in a database when not actively accessed.
Data-in-Transit

Information actively moving from one location to another over a network or between devices. This could involve communication over the internet, between servers, or data being transmitted between devices. Example include Sending an email, accessing a website, or transferring files between devices using a network connection.
Data-in-Use

Information actively processed, accessed, or utilized by a computer system or application. This occurs when the data is being used by applications or undergoing computational operations. Example: When you open and work on a document using a word processor or when a database server is actively processing queries and providing results.

Conclusion

In conclusion, encryption emerges as a critical tool in fortifying the security and confidentiality of information within the expansive landscape of the Internet. As a fundamental technique, encryption transforms readable data into encoded ciphertext, ensuring that sensitive information remains indecipherable without the corresponding decryption key.

The Encryption Algorithm, akin to a secret code, employs mathematical rules and keys, with Symmetric Encryption utilizing a shared key and Asymmetric Encryption employing a public-private key pair. Throughout the data lifecycle, encryption is vital in protecting information at rest, in transit, and in use. Robust encryption practices, exemplified by historical methods like the Caesar cipher, make unauthorized access practically impossible. As a cornerstone of cybersecurity, encryption is a crucial safeguard, upholding the integrity and privacy of digital information in an interconnected and data-driven era.

What is RC4? Is RC4 secure?

RC4, also known as Rivest Cipher 4, is a symmetric key stream cipher designed by Ron Rivest in 1987. The National Institute of Standards and Technology (NIST) has discouraged the use of RC4 in favor of more secure cryptographic algorithms. NIST has published guidelines and recommendations for cryptographic algorithms, and RC4 is generally considered insecure for applications requiring strong security.

Introduction

A stream cipher is a type of cipher that operates on data a byte at a time to encrypt that data. RC4 is one of the most commonly used stream ciphers, having been used in Secure Socket Layer (SSL)/ Transport Layer Security (TLS) protocols, IEEE 802.11 wireless LAN standard, and the Wi-Fi Security Protocol WEP (Wireless Equivalent Protocol). RC4 owes its popularity, relating to stream ciphers, to its ease of use and performance speed. Now, significant flaws mean RC4 is not used nearly as often as before.

Vulnerabilities of RC4

RC4 is not recommended for use in modern cryptographic applications due to various vulnerabilities: –

Key Biases

RC4 suffers from biases in its key scheduling algorithm, which can lead to statistical biases in the generated keystream. An attacker can exploit these biases to deduce information about the key and potentially recover parts of the plaintext.
Weaknesses in the Initial Keystream Bytes

The initial bytes generated by RC4 are particularly weak. The first few bytes exhibit biases that can be exploited to predict or guess plaintext portions.
Fluhrer, Mantin, and Shamir (FMS) Attack

The FMS attack is a specific type of attack against RC4 that focuses on the vulnerabilities in the initial keystream bytes. This attack can recover parts of the key by analyzing the biases in the generated keystream.
Bar Mitzvah Attack

This attack exploits vulnerabilities in the RC4 algorithm, allowing an attacker to recover portions of the plaintext. It is related to biases in the keystream, particularly when RC4 is used in certain protocols and configurations.
Vulnerability to Cryptanalysis

RC4 is vulnerable to various cryptanalytic techniques, and its security degrades with time as more vulnerabilities are discovered. As cryptanalysis techniques advance, the likelihood of successful attacks against RC4 increases.

Advantages and Disadvantages

Advantage	Disadvantage
Simple to use, leading to easy implementation.	Weaknesses include biases in the initial output bytes, key-dependent vulnerabilities, and the ability to recover the key from enough keystream bytes.
Fast and efficient due to its simplicity.	Limited use on smaller streams of data
Swift handling of large streams of data.	It lacks authentication, making it susceptible to Man in the Middle.

How do I disable my server from using RC4?

Servers who do not want to use the RC4 cipher suites any longer can disable its use. This can be done by setting the registry keys so that no client or server can establish a connection to another server using the RC4. Therefore, servers will not be able to provide service to clients who use RC4, and clients will not be able to connect to websites by implementing the following settings:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 128/128]

“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 40/128]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 56/128]
“Enabled”=dword:00000000

Conclusion

There is a critical need to disable RC4 to protect communications against known vulnerabilities. Therefore, implementing strong and secure cipher suites ensures adherence to compliance to industry standards such as NIST and enhances the overall security posture. Through our Encryption Assessment, we ensure that the high-risk data is encrypted per industry standards such as FIPS 140-2, NIST, and more. For Public Key Infrastructure (PKI) Audits, we use our own unique approach that is based on NIST recommendations and industry best practices.

By following the above-mentioned steps, organizations can ensure secure communications by reinforcing secure configurations and reducing the risk of malicious attacks which are targeted to exploit RC4’s weaknesses.

What is ECDSA Encryption? How does it work?

Introduction

Elliptic Curve Digital Signature Algorithm, or ECDSA, is one of the more complex public key cryptography encryption algorithms. Keys are generated via elliptic curve cryptography that are smaller than the average keys generated by digital signing algorithms. Elliptic curve cryptography is a form of public key cryptography which is based on the algebraic structure of elliptic curves over finite fields. Elliptic curve cryptography is mainly used for the creation of pseudo-random numbers, digital signatures, and more. A digital signature is an authentication method used where a public key pair and a digital certificate are used as a signature to verify the identity of a recipient or sender of information.

What is ECDSA?

ECDSA does the same thing as any other digital signing signature, but more efficiently. This is due to ECDSA’s use of smaller keys to create the same level of security as any other digital signature algorithm. ECDSA is used to create ECDSA certificates, which is a type of electronic document used for authentication of the owner of the certificate. Certificates contain information about the key used to create the certificate, information about the owner of the certificate, and the signature of the issuer of the certificate, who is a verified trusted entity. This trusted issuer is normally a certificate authority which also has a signed certificate, which can be traced back through the chain of trust to the original issuing certificate authority.

The way ECDSA works is an elliptic curve is that an elliptic curve is analyzed, and a point on the curve is selected. That point is multiplied by another number, thus creating a new point on the curve. The new point on the curve is very difficult to find, even with the original point at your disposal. The complexity of ECDSA means that ECDSA is more secure against current methods of encryption cracking encryptions. Along with being more secure against current attack methods, ECDSA also offers a variety of other benefits as well.

Advantages and Disadvantages

Advantages	Disadvantages
A newer standard was standardized in 2005.	Complex to implement, leading to potential improper implementations.
It is a shorter period since standardization reduces hacking time.	RSA, standardized in 1995, has a longer track record.
Complexity and newness make it less susceptible to attacks.	RSA is still the widely used method due to its longer establishment.
Desirable option for newer protocols for public key crypto.	RSA is simpler to set up, offering fewer roadblocks in implementation.

Vulnerabilities

The vulnerability of ECDSA (Elliptic Curve Digital Signature Algorithm), as described in the provided information, can be summarized as follows:

Implementation Complexity

ECDSA is more challenging to implement correctly than RSA, which may increase the risk of implementation errors. Poorly implemented ECDSA algorithms can compromise security.
Output Length

ECDSA provides smaller output lengths than RSA for the same level of security. A 3072-bit RSA signature is equated to the security level of a 256-bit ECDSA signature. Smaller output lengths might make ECDSA signatures more susceptible to brute-force attacks.
Choice of Elliptic Curves

Elliptic curves are critical, as some curves may enable attackers to brute-force encryption. Selecting elliptic curves that do not allow attackers to find an implementation that solves the discrete logarithm problem in polynomial time is essential.
Twist Attack

A potential vulnerability is the “twist attack,” where a malicious actor provides a set of carefully chosen points on the elliptic curve for the message receiver to cipher.
If the algorithm used by the message receiver has a poor implementation, the attacker may be able to uncover the private key from the ciphertext.
Security vs. Implementation Difficulty

The difficulty in implementing ECDSA may impact the algorithm’s security. Ensuring secure implementation is crucial to avoid vulnerabilities.

What is Twofish? Is Twofish secure?

Introduction

Twofish, a symmetric key block cipher, was developed in response to the need to replace the Data Encryption Standard (DES). In 1997, it was entered into a competition held by the National Institute of Standards and Technology (NIST) to select a new standard encryption algorithm. The competition aimed to address the shortcomings of DES, which was widely criticized for its closed-door design process. Twofish was designed to work well on smaller devices with low-power processing capabilities.

The NIST design criteria for the competition specified the need for algorithms with 128-bit symmetric block ciphers capable of handling key lengths ranging from 128 to 256 bits. The ideal algorithm should have no weak keys, feature a simple design for easy analysis, and be suitable for implementation in low-power devices and on various platforms and applications.

Vulnerabilities in Twofish

The Twofish encryption algorithm, while generally considered secure, is not without its potential vulnerabilities:

Susceptibility to Side-Channel Attacks

Twofish is vulnerable to side-channel attacks, including timing and power analysis attacks. Attackers may exploit information leaked through these channels to gain insights into the cryptographic processes, potentially compromising the algorithm’s security.
Implementation Challenges

Implementing Twofish correctly can be challenging. Errors in the implementation may introduce vulnerabilities that attackers could exploit. The algorithm’s complexity requires careful and accurate coding to ensure its secure deployment.
Resource Intensiveness

Twofish’s computational complexity might make it less suitable for low-power devices or applications with limited computing resources. The algorithm’s resource-intensive nature could impact the efficiency of its implementation in scenarios where computational overhead needs to be minimized.

Twofish’s design aimed to provide a secure and efficient alternative to DES, considering the evolving landscape of cryptographic requirements. While it was not selected as the Advanced Encryption Standard (AES), Twofish remains a respected and secure cipher. Its development and participation in the NIST competition contributed to advancing cryptographic algorithms.

Advantages and Disadvantages

Advantage	Disadvantage
Twofish is considered highly secure and has withstood extensive cryptanalysis.	The algorithm is relatively complex, which can make implementation and analysis challenging.
Twofish supports key sizes of 128, 192, and 256 bits, providing flexibility based on security requirements.	Twofish might be resource-intensive, making it less suitable for low-power devices or applications with limited computing resources.
Twofish is designed for efficient performance in software and hardware implementations.	Although the patent on Twofish has expired, some developers may still be cautious about potential legal issues.

What is Blowfish in security? Who uses Blowfish?

Introduction

Blowfish, a symmetric-key block cipher, emerged on the cryptographic scene in 1993 through the efforts of Bruce Schneier. This algorithm was designed to be a versatile, secure, and swift alternative to existing encryption methods. Notably, Schneier’s philosophy behind Blowfish was groundbreaking for its time – he made the algorithm unpatented and freely available to the public. This openness contributed significantly to Blowfish’s widespread adoption in diverse applications and systems.

Vulnerabilities of Blowfish

Key Change Impact on Speed

Changing keys in Blowfish can negatively impact speed. This limitation could be a concern when frequent key changes are required.
Lengthy Key Schedule

The key schedule process in Blowfish takes considerable time. This can be a drawback, especially when a quick key setup is essential.
Vulnerability to Brute-force Attacks

Blowfish’s small 64-bit block size makes it susceptible to a class of brute-force attacks. The collision probability (two different inputs producing the same output) increases with the limited block size, potentially compromising security.
Resource-Intensive Key Preprocessing

Introducing a new key in Blowfish requires preprocessing equivalent to 4 KB of text. This preprocessing level, especially for each new key, can impact the speed and efficiency of the algorithm, making it less suitable for certain applications.

In response to these concerns, Bruce Schneier and other cryptography experts developed Twofish as a successor to Blowfish. Twofish participated in the AES competition held by the National Institute of Standards and Technology (NIST) to determine the Advanced Encryption Standard (AES).

Despite not being chosen as the AES, Blowfish has left an indelible mark on cryptographic history. Its legacy persists, and it continues to find application in various contexts. While not considered state-of-the-art today, the historical significance of Blowfish remains notable within the broader narrative of cryptographic advancements.

Advantages and Disadvantages

Advantages	Disadvantages
Faster than other encryption algorithms, such as the Data Encryption Standard (DES)	The key schedule of Blowfish takes a long time, equivalent to encrypting 4KBs of data, which can be a disadvantage or an advantage. On the Disadvantage side, it takes a very long time to do
Blowfish is unpatented and free to use. This means anyone can take and use Blowfish for whatever they want to	The small block size of Blowfish means that Birthday Attacks can occur and compromise the encryption algorithm
The Blowfish algorithm also has a lesser amount of operations to complete compared to other encryption algorithms	It is followed by Twofish, which was created to replace Blowfish, as it is better in most ways
The key schedule of Blowfish takes a long time, but this can be advantageous, as brute force attacks are more difficult

But like any other technology, Blowfish has its share of weaknesses. One of its weaknesses is how major variables affect speed, which is especially problematic in situations where key turning is required. Longer master plans are a different story, and take more time to get started. Due to the small size of a Blowfish 64-bit block, it is vulnerable to brute-force attacks, increasing the chances of collisions and potentially compromising security

Despite its disadvantages, blowfish have many advantages. Its off-patent status encourages widespread use, and its pace exceeds that of its predecessors, including the Data Encryption Standard (DES). The popularity of an algorithm also affects its efficiency.

However, the field of cryptography is constantly evolving, and due to its shortcomings, Twofish emerged as an alternative to Blowfish. While Bifish is not designated as an Advanced Encryption Standard (AES), it marks the beginning of a new era of encryption by addressing many of the shortcomings of Blowfish

Blowfish is a legendary algorithm in the history of cryptography, its influence continues even in the face of recent and sophisticated algorithms His journey represents a step forward in the continued pursuit of secure communications in the digital age and proof of it shows the development of cryptographic techniques

What is Format Preserving Encryption (FPE)? Is Format Preserving Encryption secure?

Format Preserving Encryption, or FPE, is an encryption algorithm which preserves the format of the information while it is being encrypted. FPE is weaker than standard Advanced Encryption Standard (AES), but FPE can preserve the length of the data as well as its format. FPE works with existing databases to encrypt data while keeping it in the same format, encrypting data while not harming the function of existing applications.

Format Preserving Encryption (FPE)

FPE encrypts takes plai n text and converts it to ciphertext, of the same format. An example of this is seen above. By keeping the format the same, an application can do operations on data as if it were the plaintext, while not revealing the sensitive information encrypted. Personally Identifiable Information (PII), credit card information, social security numbers, and other sensitive data are normally encrypted with Format Preserving Encryption. FPE has three different modes of operation: FF1, FF2, and FF3, which are referred to as FFX as a whole.

All three of the operation methods utilize the AES block cipher within their encryption. The second mode, FF2, was created but never approved by the National Institute of Standards and Technology (NIST). Instead, FF1 and FF3 were approved. FF1 is the most commonly used version, because of a cryptanalytic attack performed on the FF3 method which showed it held flaws. This attack found that the proposed 128-bit level of security was not reached. In response, a method called FF3-1 was created in early 2019 which addressed these issues.

FPE works extremely well with existing applications as well as new applications. If an application needed data of a certain length and format, then FPE could be applied to the data to encrypt it while not necessitating the changing of the application. This works particularly well with software that cannot handle long strings of data. Format Preserving Encryption is a valid encryption algorithm to be used for compliance with NIST standards. An NIST publication, called NIST 800-38G, was created to address FPE. This NIST publication focuses on the three methods of Format Preserving Encryption, describing the technical details of each mode of operation.

FPE on the Cloud

Many vendors offer FPE with their services, including Comforte, HashiCorp, Futurex and Xmart Solutions. Some cloud service providers (CSPs) offer options to utilize FPE within their platform, but far fewer than regular vendors. Of the three biggest CSPs, Microsoft Azure, Amazon Web Services (AWS), and Google Cloud Platform (GCP), only GCP offers users the ability to work with Format Preserving Encryption.

Using FFX, Google Cloud Platform allows users to have access to FF1 and FF3 FPE methods, though FF1 is the more commonly used method. FFX uses multiple rounds of a Feistel function on the plaintext, along with a key, to create the ciphertext. A Feistel function splits the plaintext into two parts, permutates the text to change what it looks like, and then swaps the left half of text to the right and vice versa. The FF1 method uses 10 rounds of a Feistel function, and FF3 uses 8 rounds.

For a user utilizing the Data Loss Prevention (DLP) API in GCP, to encrypt with FFX, an alphabet to be used to encrypt the plaintext must be specified. This can be done by using a shortened name of one of the four most common alphabet types. NUMERIC specifies numbers 0-9, HEXADECIMAL includes the NUMERIC alphabet along with A-F, UPPER_CASE_ALPHA_NUMERIC is for 0-9 and A-Z, and ALPHA_NUMERIC specifies 0-9, A-Z and a-z. Users can also use a radix value specifying the size of the alphabet. Specifying 2 gives an alphabet consisting of the numbers 0 and 1, while specifying 95 gives an alphabet with all numeric, upper-case alpha, lower-case alpha, and symbol characters. The last way to specify the alphabet is by providing the exact numbers, symbols, and letters that are in the alphabet.

Encrypting with FPE on GCP can result in an image like the previous image, or a surrogate annotation may precede the ciphertext, if the data is unstructured. A ciphertext with a surrogate annotation will follow this format:

SURROGATE_INFOTYPE(SURROGATE_LENGTH): SURROGATE_VALUE

The surrogate_infotype is chosen by the user and can be any word. The surrogate_length tells how long the surrogate_value is, and the surrogate_value is the ciphertext itself. An example of ciphertext with a surrogate annotation is:

FaKeInFoTyPe(13): 182-123-3596

FPE with Encryption Consulting

Encryption Consulting offers blogs providing information for any organization or user wanting to learn more about FPE. We also provide resources that utilize Google Cloud Platform’s FPE options. Bucket Protector and Cloud Data Protector both work with the DLP and Key Management Services (KMS) APIs to encrypt data being sent to Google Cloud Storage or data on an organization’s local database with FPE. Bucket Protector and Cloud Data Protector fall under the Cloud Data Lake Protection services offered by Encryption Consulting, protecting data at the Data Storage and Data Ingestion phases of the Cloud Data Lake Lifecycle.

What is RSA? How does an RSA work?

Introduction

The Rivest-Shamir-Adleman (RSA) encryption algorithm is an asymmetric encryption algorithm that is widely used in many products and services. Asymmetric encryption uses a key pair that is mathematically linked to enc r ypt and decrypt data. A private and public key are created, with the public key being accessible to anyone and the private key being a secret known only by the key pair creator. With RSA, either the private or public key can encrypt the data, while the other key decrypts it. This is one of the reasons RSA is the most used asymmetric encryption algorithm.

How does RSA work?

The option to encrypt with either the private or public key provides a multitude of services to RSA users. If the public key is used for encryption, the private key must be used to decrypt the data. This is perfect for sending sensitive information across a network or Internet connection, where the recipient of the data sends the data sender their public key. The sender of the data then encrypts the sensitive information with the public key and sends it to the recipient. Since the public key encrypted the data, only the owner of the private key can decrypt the sensitive data. Thus, only the intended recipient of the data can decrypt it, even if the data were taken in transit.

The other method of asymmetric encryption with RSA is encrypting a message with a private key. In this example, the sender of the data encrypts the data with their private key and sends encrypted data and their public key along to the recipient of the data. The recipient of the data can then decrypt the data with the sender’s public key, thus verifying the sender is who they say they are. With this method, the data could be stolen and read in transit, but the true purpose of this type of encryption is to prove the identity of the sender. If the data were stolen and modified in transit, the public key would not be able to decrypt the new message, and so the recipient would know the data had been modified in transit.

The technical details of RSA work on the idea that it is easy to generate a number by multiplying two sufficiently large prime numbers together, but factorizing that number back into the original prime numbers is extremely difficult. The public and private key are created with two numbers, one of which is a product of two large prime numbers. Both use the same two prime numbers to compute their value. RSA keys tend to be 1024 or 2048 bits in length, making them extremely difficult to factorize, though 1024 bit keys are believed to breakable soon.

Who uses RSA encryption?

As previously described, RSA encryption has a number of different tasks that it is used for. One of these is digital signing for code and certificates. Certificates can be used to verify who a public key belongs to, by signing it with the private key of the key pair owner. This authenticates the key pair owner as a trusted source of information. Code signing is also done with the RSA algorithm. To ensure the owner is not sending dangerous or incorrect code to a buyer, the code is signed with the private key of the code creator. This verifies the code has not been edited maliciously in transit, and that the code creator verifies that the code does what they have said it does.

RSA was used with Transport Layer Security (TLS) to secure communications between two individuals. Other well-known products and algorithms, like the Pretty Good Privacy algorithm, use RSA either currently or in the past. Virtual Private Networks (VPNs), email services, web browsers, and other communication channels have used RSA as well. VPNs will use TLS to implement a handshake between the two parties in the information exchange. The TLS Handshake will use RSA as its encryption algorithm, to verify both parties are who they say who they are.

RSA Vulnerabilities

Though viable in many circumstances, there are still a number of vulnerabilities in RSA that can be exploited by attackers. One of these vulnerabilities is the implementation of a long key in the encryption algorithm. Algorithms like AES are unbreakable, while RSA relies on the size of its key to be difficult to break. The longer an RSA key, the more secure it is. Using prime factorization, researchers managed to crack a 768 bit key RSA algorithm, but it took them 2 years, thousands of man hours, and an absurd amount of computing power, so the currently used key lengths in RSA are still safe. The National Institute of Science and Technology (NIST) recommends a minimum key length of 2048 bits now, but many organizations have been using keys of length 4096 bits. Other ways RSA is vulnerable are:

Weak Random Number Generator

When organizations use weak random number generators, then the prime numbers created by them are much easier to factor, thus giving attackers an easier time of cracking the algorithm.
Weak Key Generation

RSA keys have certain requirements relating to their generation. If the prime numbers are too close, or if one of the numbers making up the private key is too small, then the key can be solved for much easier.
Side Channel Attacks

Side channel attacks are a method of attack that take advantage of the system running the encryption algorithm, as opposed to the algorithm itself. Attackers can analyze the power being used, use branch prediction analysis, or use timing attacks to find ways to ascertain the key used in the algorithm, thus compromising the data.

What is AES? How does it work?

Introduction

The Advanced Encryption Standard (AES), introduced by the National Institute of Standards and Technology (NIST) in 2001, is a strong encryption algorithm derived from the Rijndael cipher family. AES employs the Rijndael block cipher to enhance security with three distinct key sizes: 128, 192, and 256 bits. It operates as a symmetric block cipher, employing a single key for encryption and decryption processes. In contrast to asymmetric encryption, which utilizes two keys, AES simplifies the process by relying on a single secret key. Initially exclusive to the United States, AES has gained global recognition, becoming one of the most widely adopted and secure encryption algorithms, symbolizing its effectiveness and adaptability in safeguarding sensitive information worldwide.

Why was AES developed?

DES was established as the encryption standard by NIST in the early 1970s and was widely adopted by the U.S. government and other organizations. However, with the passage of time and the advancement of computing power, DES’s 64-bit key size (56 usable bits) became a security concern. The relatively small key size made DES susceptible to brute-force attacks, where an attacker could guess the key through repeated attempts.

In response to DES’s limitations, NIST initiated a process to select a new encryption standard that would offer a higher level of security while being efficient and practical for widespread adoption. In 1997, NIST issued a public call for cryptographic algorithms, inviting submissions from the global cryptographic community.

The Bureau of Industry and Security (BIS) has several controls and regulations in place that make it difficult to export encrypted products encrypted with AES. The Rijndael algorithm, chosen as the basis for AES, provided a solid foundation for encryption. It operated on 128-bit blocks of data, ensuring high security. AES has become a widely accepted encryption standard published by NIST for various frameworks and regulations.

Understanding Key Size differences

AES’s block cipher encrypts data by breaking the plaintext into 128-bit blocks. Encryption involves bitwise operations using keys of varying lengths—128, 192, or 256 bits. The key size directly impacts security, with larger keys providing greater protection. For a 128-bit key, encryption occurs ten times, 12 times for 192 bits, and 14 times for 256 bits. While 256-bit keys offer the highest security, 128-bit keys are generally sufficient for most cases. The key size choice depends on the data’s security requirements, where higher security levels warrant larger key sizes. AES provides flexibility in key selection to cater to diverse encryption needs.

Specification	AES-128	AES-192	AES-256
Key Length (bits)	128 bits	192 bits	256 bits
Number of Rounds	10 rounds	12 rounds	14 rounds
Key Schedule Size	176 bytes	208 bytes	240 bytes
Encryption Strength	Moderate	Higher	Strongest

How does it work?

AES (Advanced Encryption Standard) is a symmetric encryption algorithm that applies transformations to plaintext data to produce ciphertext. Here’s a high-level overview of how AES works:

Key Expansion

AES operates on fixed-size blocks of data (128 bits in the case of AES-128). The secret key, 128, 192, or 256 bits long, undergoes a key expansion process to generate a set of round keys. Each round key is derived from the original key and is used in the successive encryption rounds.
Initial Round
- AddRoundKey
  
  Each block byte is combined with the corresponding byte of the round key using bitwise XOR.
Rounds (9 or 11 rounds for AES-128 or AES-256, respectively)
- SubBytes
  
  Non-linear substitution step where each byte in the block is replaced with a corresponding byte from the S-box.
- ShiftRows
  
  A transposition step where varying offsets shift the rows of the block.
- MixColumns
  
  A mixing operation that operates on the columns of the block, providing diffusion.
- AddRoundKey
  
  Similar to the initial round, each byte of the block is XORed with the corresponding byte of the round key.
Final Round (differs for AES-128, AES-192, and AES-256)

MixColumns are not performed for AES-128 in the final round. The number of rounds and the key size determine the number of transformation rounds.
Decryption

The decryption process is essentially the reverse of encryption. It involves an inverse series of transformations using a set of round keys derived from the original key.

Example

Let’s consider a brief example of encrypting a message “CONFIDENTIAL” using AES-256:

Key Generation

Generate a strong 256-bit key for AES-256 encryption.

Encryption

Apply the AES encryption process with 14 rounds (AES-256). Each round involves substitution, shifting, mixing, and further encryption steps. For simplicity, let’s represent the encryption result as “X1Y2Z3…”.

Ciphertext

The encrypted message, or ciphertext, is now “X1Y2Z3…” and appears as random data.

Now, imagine sending this ciphertext over the internet. The recipient, possessing the same 256-bit key, can use the reverse process to decrypt the message and reveal the original content “CONFIDENTIAL.” The security of AES-256 ensures that even with significant computational power, attempting to decipher this message without the proper key would be practically impossible within a reasonable timeframe.

Where can it be implemented?

AES (Advanced Encryption Standard), initially developed by NIST for government use, has become a cornerstone in public and private applications. It finds applications in diverse sectors, such as VPNs, password managers, mobile applications, wireless networks, file encryption, and video games.

For instance, in VPNs like PureVPN, AES secures internet traffic, while password managers like Keeper use AES to protect stored passwords. Video game developers leverage AES to combat piracy by encrypting game data.

AES is also employed in critical areas, including encrypting data on hard drives, securing electronic communications in messaging apps, and forming an integral part of programming libraries such as Java, Python, and C++. Its role extends to file compression programs and internet browsers.

Advantages and disadvantages

Advantage	Disadvantage
AES is a globally recognized and widely adopted encryption standard.	AES-256, especially, can be computationally intensive, requiring more processing power.
AES provides advanced security against various cryptographic attacks, ensuring data confidentiality.	Proper key management is crucial for AES. The security is only as strong as the protection of the encryption keys.
ES can be used for various applications, from securing data on hard drives to internet communications.	As quantum computing evolves, it may threaten AES, although this is a concern for the distant future.
Offers flexibility with key sizes (128-bit, 192-bit, and 256-bit) to cater to different security needs.	Side-channel attacks, where attackers exploit information leaked during encryption, could pose a threat.
Being a NIST-approved standard, AES is recommended for government and private-sector use.	The initial key setup and distribution can be a logistical challenge, especially in large systems.

Comparison between AES, Triple-DES, DES

Feature	DES	Triple- DES	AES
Full Name	Data Encryption Standard	Triple Data Encryption Algorithm	Advanced Encryption Standard
Year Introduced	1976	1998 (as a response to DES limitations)	1999
Key Length	56 bits (weak)	112 or 168 bits (only 112 bits secure)	128, 192, or 256 bits
Block Size	64 bits	64 bits	128 bits
Security	Weak, vulnerable to brute-force attacks	It is more secure than DES but still considered less secure than AES	Strong, no known successful attacks

What is Stream Cipher and Block Cipher?

What-is-Triple-Data-Encryption-Standard_

What is a Block Cipher?

A block cipher is a cryptographic algorithm that encrypts fixed-size data blocks, commonly 128 bits. It operates with a fixed key and encrypts data groups to ensure maximum confidentiality and security. Modern block ciphers are based on the iterated product cipher design, using a fixed key for encrypting data groups.

How does Block Cipher work?

In a block cipher, encryption occurs in fixed-length blocks, typically chunks of 128 bits. Block ciphers operate on larger data units than stream ciphers, which encrypt one byte at a time. A key, denoted as K, transforms each plaintext block into a corresponding ciphertext block.

Key features and benefits of the block cipher:

Block Size

Encryption is performed on fixed-size blocks, often consisting of 128 bits. Each block undergoes a series of transformations using the encryption key.
Key Expansion

The encryption key, K, is expanded to produce subkeys for each round of encryption, enhancing the security of the block cipher.
Confusion and Diffusion

Confusion involves complexing the relationship between the key and ciphertext. Diffusion ensures that a change in one part of the plaintext affects a large portion of the ciphertext.
Rounds of Transformation

Each block undergoes multiple rounds of transformation, each involving substitution, permutation, and mixing operations.
Cryptographic Security

Block ciphers are designed to resist various cryptographic attacks, including differential and linear cryptanalysis. The careful design of the cipher’s structure achieves robust security.
Electronic Codebook (ECB) Mode

Each block is independently encrypted in ECB mode. Identical plaintext blocks yield identical ciphertext blocks.
Cipher Block Chaining (CBC) Mode

CBC mode introduces an initialization vector (IV) to enhance security. Before encryption, each block is XORed with the previous ciphertext block.

Example Encryption:

The encryption process involves multiple rounds of substitution and permutation.
Each block of plaintext is transformed into a corresponding block of ciphertext.

Example Decryption:

Decryption reverses the encryption process, applying inverse transformations.
Each block of ciphertext is decrypted to reveal the original plaintext.

Block ciphers are foundational in various cryptographic protocols, ensuring secure communication and data protection across diverse applications. Their fixed block size and complex encryption mechanisms contribute to their resilience against attacks.

What is Stream Cipher?

Encryption is performed one byte at a time in a stream cipher, providing a continuous stream of pseudorandom bits for increased security. The process begins with initializing a key, denoted as k, which is fed into a pseudorandom bit generator. This generator produces an 8-bit keystream, serving as the foundation for encryption.

Key features and benefits of the stream cipher:

Keystream Generation
- A key, k, is input into a pseudorandom bit generator.
- The generator produces an 8-bit keystream, forming the basis for encryption.
Cryptanalysis Resistance
- The sequential nature of stream ciphers enhances resistance against cryptanalysis.
- Increasing the length of the keystream makes cryptanalysis more challenging.
Brute Force Protection
- Longer keys contribute to resistance against brute force attacks.
- Strengthening security is achieved by employing longer key lengths.
Efficient Keystream Design
- Keystreams are designed for optimal efficiency, incorporating a balanced mix of 1s and 0s.
- This design choice aims to heighten the complexity of cryptanalysis.
Stream Cipher Operation
- The encryption process
  
  It involves XORing each plaintext bit with the corresponding bit in the keystream
  
  Example: Plain Text: 10011001, Keystream: 11000011, Cipher Text: 01011010
- Decryption process
  
  Decryption mirrors the encryption process using the same keystream. XORing the ciphertext with the keystream yields the original plaintext.
  
  Example: Cipher Text: 01011010, Keystream: 11000011, Plain Text: 10011001
The stream cipher’s simplicity, efficiency, and cryptographic strength make it suitable for various applications where real-time encryption and decryption are crucial.

What is Triple Data Encryption Standard?

Initially, DES served as the standard for digital communications, showcasing the early strides in encryption technology. However, with advancements in computing power, DES became vulnerable to hacking, as it could be compromised in a matter of hours.

Triple DES emerged, refining the security landscape by applying the DES algorithm three times. This triple-layered approach with multiple keys significantly bolstered resistance against modern computational threats, offering a more robust and secure encryption solution.

How does it work?

Here’s a basic overview of how Triple DES works:

Key Expansion

Triple DES uses three 56-bit keys labeled Key1, Key2, and Key3. If a 168-bit key is provided, it’s used as is. If a 112-bit key is provided, it’s repeated to form a 168-bit key.
Encryption Process

The data is divided into blocks of 64 bits. The encryption process involves three stages: encryption with Key1, Decryption with Key2, and Encryption with Key3 (EDE—Encrypt, Decrypt, Encrypt).
Decryption Process

The process for decryption is reversed: decryption with Key3, Encryption with Key2, and Decryption with Key1.
Key Usage

Each key is used for a different phase, providing a threefold application of the DES algorithm. Using three keys in a cascade provides an effective key length of 168 bits, making Triple DES more secure than single DES.
Strengths and Security

Triple DES aims to address the vulnerabilities of a single DES by applying the algorithm multiple times. While more secure than single DES, Triple DES is considered slow compared to modern encryption algorithms like AES.
Variants

There are variations in how Triple DES is implemented. For example, some modes use two keys (EEE or EDE) instead of three, depending on specific security requirements.

Example

In a 3DES scenario, consider the plaintext message “HELLO123” and three keys: K1, K2, and K3.

The encryption process begins

By encrypting the message with the first key, K1, creating an intermediate ciphertext. Subsequently, this intermediate result undergoes decryption using K2, followed by a final encryption with K3.
The outcome

Outcome of this three-step process is the secure ciphertext representation of the original message
For decryption

The reverse steps are executed – decrypting with K3, encrypting with K2, and finally decrypting with K1 – leading to recovering the original “HELLO123” plaintext.

Using three keys in 3DES and the intricate encryption-decryption sequence heightens security compared to the single DES algorithm.

Advantages and disadvantages

Advantages	Disadvantages
The triple-layered encryption provides increased security compared to the original DES.	3DES is slower than modern encryption algorithms like AES, impacting processing efficiency.
3DES retains compatibility with existing DES implementations, facilitating gradual transitions.	While stronger than DES, 3DES’s effective key length is limited, especially when using three 56-bit keys.
3DES can be used for a single DES by setting all three keys to the same value, ensuring backward compatibility.	The triple encryption process demands more computational resources, affecting performance in resource-constrained environments.
3DES is widely supported and integrated into various applications, protocols, and hardware.	Although more secure than DES, 3DES has a smaller security margin than advanced encryption standards like AES.