This chapter is dedicated to the most important and useful cryptanalytic and cryptanalysis standards, validation methods, classification, and operations of cryptanalysis attacks. The cryptanalysis discipline is very complex, and writing about it takes thousands of research hours. The following sections contain a survey of the most important elements that are vital for you to use in your daily activities.
Standards
The importance of standards is vital and it should be known by any professional when a cryptanalysis attack is conducted. Most cryptanalysis attacks are conducted for business purposes only. Any cryptanalysis activity outside of government use and business purpose is not legal and should not be performed for personal gain.
Organizations are very exposed to security attacks and it is very important to make sure that the organization meets the necessary requirements regarding the security of its data. Any organization can hire security experts to perform cryptanalysis attacks in order to test its security and to find the vulnerabilities which later might be exploited by a malicious user/attacker.
IEFT Public-Key Infrastructure (X.509): The organization focuses on the standardization of the protocols used on the Internet that are based on public key systems.
National Institute of Standards and Technologies (NIST): The institute focuses on the elaboration of standards FIPS for the U.S. government.
American National Standards Institute (ANSI): Its goal is to maintain standards from the private sector.
Internet Engineering Task Force (IEFT): It represents an international community formed out of networks, operators, and traders of services and researchers. Their main purpose is represented by the evolution of the Internet architecture.
Institute of Electrical and Electronical Engineering (IEEE): Its goal is to design theories and advanced techniques from different fields, such as electronics, computers sciences, and informatics.
International Organization for Standardization (ISO): It is a non-governmental organism that includes more than 100 countries. Its main goal is to encourage the development of standardization to help professionals to facilitate the international exchange of services.
FIPS 140-2, FIPS 140-3, and ISO 15408
ISO 154081 is one of the most important standards in the evaluation of IT security and it is used in the international community as a reference system standard. The standard includes a set of rules and requirements from IT field. The goal is to validate the security of the product and cryptographic systems.
FIPS 140-2 and 140-3 offer guidelines that need to be respected in order to accomplish a specific set of technical requirements which are divided and exposed on four levels.
You need to take into consideration both standards, FIPS 140-2/FIPS 140-3 and ISO 15408, when a specification or criterion is developed for a specific application or cryptographic module.
The products that are developed based on the standards need to be tested. The goal of the tests is to get validation and to confirm that the criteria were followed and respected properly.
Validation of Cryptographic Systems
If the business requires cryptanalysis and cryptography operations to be implemented within the software and communication systems, then cryptographic and cryptanalysis services are required. These services are authorized by certification organisms and they include functionalities such as digital signature generation and verification, encryption and decryption, key generation, key distribution, key exchange, etc.
Verification and testing framework
Attacks on Ciphering Algorithms
Types of Attacks on Ciphering Algorithms | |
|---|---|
Attack Title | Attack Description |
Known Plaintext Attack | The cryptanalyst has an encrypted text and the plaintext as its correspondent. The purpose of this attack is for the cryptanalyst to separate the encryption key from the data. |
Chosen Text Attack | The cryptanalyst has the option of indicating the plaintext that is to be encrypted. By using this type of attack the cryptanalyst may attempt to isolate the text information from the encryption key with the possibility of accessing the encryption algorithm or the key by different methods. |
Cipher-Cipher Text Attack | The cryptanalyst keeps the same text, which is encrypted with two or more different keys in plaintext and its correspondent. |
Divide-et-Impera Attack | The cryptanalyst has the ability to realize a set of associations between different algorithm inputs and outputs with the intention of separating different algorithm inputs, which lets him split the problem into two or more easily solved problems. |
Linear Syndrome Attack | The cryptanalysis method consists of designing and creating a pseudorandom generator-specific linear equation system and verifying the equation system with the encrypted text, thus obtaining a high probability plaintext. |
Consistency Linear Attack | The cryptanalytic method consists of the creation of a pseudorandom generator-specific linear equation scheme starting from an analogous cryptographic key and checking the scheme by the pseudorandom generator with the probability that goes to 1, thus obtaining a high probability plaintext. |
Stochastic Attack | Known as a forecasting attack, the attack is possible if the output of the generator is autocorrelated and the cryptanalyst manages to obtain as input data the output of the pseudorandom generator and the encrypted text. In this way the clear text is obtained. |
Informational Linear Attack | Known also as a linear complexity attack, it is possible to attack if there is any chance of equalizing the generator with a Fibonacci algorithm and if the linear complexity is equivalent to the low generator. With this type of attack a similar algorithm and similar cryptographic key can be constructed. |
Virus Attack | This attack is possible if it applies the encryption algorithm and operates on a vulnerable and unprotected PC. |
For a sufficient testing and verification process, at minimum you need the cryptographic module and the cryptographic/cryptanalysis algorithm . For any cryptographic product (or desktop/web software application) developed it is necessary to perform tests and submit the product to CMVP2 (Cryptographic Module Validation Programme) in order to be tested with respect to FIPS 140-23 and FIPS 140-3.4
Minimum requirements should be satisfied by the modules.
Authorized and technical personnel should be informed and instructed within a standard. The standard is commonly agreed upon and that it was tested.
Verify that the end user is aware that the cryptographic module has been verified and tested according to security requirements defined before developing the cryptographic module.
A high level of reliability for security needs to be fulfilled with the goal of developing similar and specific applications.
The security requirements that characterize FIPS 140-2 have 11 metrics and criteria that can be used during the design and implementation process of the cryptographic modules. The cryptographic module has to fulfill and validate each of the metrics. During the validation process, a mark from 1 to 4 is assigned to the cryptographic module, proportional with the security level guaranteed.
Once the cryptographic modules are validated, a set of information should be included such as the name of the manufacturer, address, the name of the module, the version of the module, type of module (software or hardware), validation date, validation level, and module description.
Cryptanalysis Operations
The adversary should not be underestimated.
A cryptographic system can be evaluated by a cryptanalyst.
Before evaluating the cryptographic system, the adversary’s knowledge of the assessed cryptosystem is taken into account.
The secrecy of the cryptographic system relies on the key.
All elements within the system such as key distribution, cryptographic content, and so on must be taken into account in the cryptographic system evaluation process.
One of the winnings of the cryptanalyst is gained once the message is decrypted with success.
Key length and complexity
The level of complexity of the encryption-deciphering process
The size of the encoded text according to the document size
The way to propagate errors
Finding and deciding the vocabulary used
Deciding the cryptographic system
Reconstruction of a single key for a cryptographic system or partial or complete reconstruction for a cryptographic stream system
Reconstruction of such scheme or determining the complete plaintext
Classification of Cryptanalytics Attacks
This section discusses the types of attacks against cipher algorithms, cryptographic keys, authentication protocols, systems themselves, and hardware attacks.
Attacks on Cipher Algorithms
Attacks on Cryptographic Keys
Types of Attacks on the Keys | |
|---|---|
Attack Title | Attack Description |
Brute force Attack | The attack requires rigorous checking of the keys and passwords and is possible if the size of the encryption key is small and the space of the encryption key is small. |
Intelligent Brute Force Attack | The randomness degree of the encryption key is small (entropy is small), which allows the password to be identified because it is close to the language used terms. |
Backtracking Attack | The attack is based on implementing a type of backtracking method, which consists of the existence of conditions for continuing the search in the direction desired. |
Greedy Attack | The attack provides the optimal local key (the optimal global key cannot be the same). |
Dictionary Attack | The attack involves searching for passwords or keys and is carried out using a dictionary. |
Hybrid Dictionary Attack | This attack is achieved by changing the dictionary terms and initializing the attack by brute force with the aid of the dictionary words. |
Viruses Attack | If the keys are stored on an unprotected PC, this attack is possible. |
Password Hash Attack/Cryptographic Key | This attack occurs if the password hash is elaborated poorly or incorrectly. |
Substitution Attack | The original key is replaced by a third party and repeated in the network. It can be achieved using viruses. |
Storing Encryption Key | If this is done in the plaintext without any physical protection measures or cryptographic, software, or hardware in the wrong way (together with the encryption data), this can lead to an attack on the encrypted message. |
Storing of Old Encryption Keys | This attack will lead to a compromised version of the old encrypted documents. |
Key Compromise | If the symmetric key is compromised, then only the documents assigned to that key will be compromised. If the public key is compromised, which can be found stored on various servers, then the attacker can replace the data’s legal owner, resulting in a bad and negative impact within the network. |
Master Keys | The cryptographic system represents various phases. |
Key Lifetime | It is an integral component that excludes a yet undetected possibility of a successful attack. |
Attacks on Cryptographic Keys
Table 19-2 lists the most common attacks that occur on cryptographic keys.
Attacks on Authentication Protocols
Attacks on Authentication Protocols
Types of Attacks on Authentication Protocols | |
|---|---|
Attack Title | Attack Description |
Attack on the Public Key | The attack within the protocol takes place for the signature. It is only available for public-key schemes. |
Attack on the Symmetric Algorithm | Inside the authentication protocol the attack must take place on the signature. This is only possible through the use of a symmetric key. |
Passive attack | The intruder can intercept and track the contact on the channel without interfering in any way. |
Attack using a third person | The two partners' correspondence inside a channel of communication is deliberately intercepted by a third-party user. |
The Fail-Stop Signature | It is a cryptographic protocol in which the sender can provide evidence of whether or not his signature was forged. |
Conclusions
The classification of cryptanalysis attacks
Operations involved in the cryptanalysis process
The FIPS 140-2 and FIPS 140-3 Standards
The ISO 15408 Standard
The cryptographic systems validation process
Bibliography
- [1]
Adrian Atanasiu, Matematici in criptografie. US Publishing House, Editor: Universul Stiintific, ISBN: 978-973-1944-48-7. 2015.
- [2]
Adrian Atanasiu, Securitatea Informatiei vol 1 (Criptografie), InfoData Publishing House, ISBN: 978-973-1803-18-0. 2007.
- [3]
Adrian Atanasiu, Securitatea Informatiei vol 2 (Protocoale de securitate), InfoData Publishing House, ISBN: 978-973-1803-18-0. 2009.
- [4]
S.J. Knapskog, “Formal specification and verification of secure communication protocols” (pp 58–73). https://link.springer.com/chapter/10.1007/BFb0030352.
- [5]
K. Koyama, “Direct demonstration of the power to break public-key cryptosystems,” (pp. 14–21). www.iacr.org/cryptodb/data/paper.php?pubkey=279.
- [6]
P.J. Lee, “Secure user access control for public networks,” (pp 46–57). www.sciencedirect.com/science/article/pii/S0140366416300652.
- [7]
R. Lidl and W.B. Muller, “A note on strong Fibonacci pseudoprimes” (pp. 311–317). https://link.springer.com/article/10.1007/BF01810848.
- [8]
Alfred J. Menezes and Scott Vanstone, “The implementation of elliptic curve cryptosystems” (pp. 2–13). https://link.springer.com/article/10.1007/BF00203817.
- [9]
M.J. Mihaljević and J.D. Golić, “A fast iterative algorithm for a shift register initial state reconstruction given the noisy output sequence” (pp. 165–175). Advances in Cryptology—AUSCRYPT ‘90, Lecture Notes in Computer Science, vol. 453, Springer-Verlag, Berlin, 1990.