Can we tell how many irreducible polynomial exist for GF(2^m) ?
In the field of classical cryptography, specifically in the context of the AES block cipher cryptosystem, the concept of Galois Fields (GF) plays a crucial role. Galois Fields are finite fields that are extensively used in cryptography for their mathematical properties. In this regard, GF(2^m) is of particular interest, where m represents the degree of
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, AES block cipher cryptosystem, Introduction to Galois Fields for the AES
Why in FF GF(8) irreducible polynomial itself does not belong to the same field?
In the field of classical cryptography, particularly in the context of the AES block cipher cryptosystem, the concept of Galois Fields (GF) plays a crucial role. Galois Fields are finite fields that are used for various operations in AES, such as multiplication and division. One important aspect of Galois Fields is the existence of irreducible
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, AES block cipher cryptosystem, Introduction to Galois Fields for the AES
At the stage of S-boxes in DES since we are reducing fragment of a message by 50% is there a guarantee we don’t loose data and message stays recoverable / decryptable?
At the stage of S-boxes in the Data Encryption Standard (DES) block cipher cryptosystem, the reduction of the message fragment by 50% does not result in any loss of data or render the message unrecoverable or undecryptable. This is due to the specific design and properties of the S-boxes used in DES. To understand why
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, DES block cipher cryptosystem, Data Encryption Standard (DES) - Encryption
In case of an attack on a single LFSR, if attackers capture 2m bits from the middle of transmission (message) can they still calculate configuration of the LSFR (values of p) and can they decrypt in backwards direction?
In the field of classical cryptography, stream ciphers are widely used for encryption and decryption of data. One of the common techniques used in stream ciphers is the utilization of linear feedback shift registers (LFSRs). These LFSRs generate a keystream that is combined with the plaintext to produce the ciphertext. However, the security of stream
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, Stream ciphers, Stream ciphers and linear feedback shift registers
What is the difference between a MAC and HMAC, and how does HMAC enhance the security of MACs?
A Message Authentication Code (MAC) is a cryptographic technique used to ensure the integrity and authenticity of a message. It involves the use of a secret key to generate a fixed-size tag that is appended to the message. The receiver can then verify the integrity of the message by recomputing the tag using the same
What is the purpose of a message authentication code (MAC) in classical cryptography?
A message authentication code (MAC) is a cryptographic technique used in classical cryptography to ensure the integrity and authenticity of a message. The purpose of a MAC is to provide a means of verifying that a message has not been tampered with during transmission and that it originates from a trusted source. In classical cryptography,
What are the weaknesses of the secret prefix and secret suffix methods for constructing MACs?
The secret prefix and secret suffix methods are two commonly used techniques for constructing Message Authentication Codes (MACs) in classical cryptography. While these methods have their advantages, they also possess certain weaknesses that need to be considered when implementing MACs. In this answer, we will explore the weaknesses of both the secret prefix and secret
- Published in Cybersecurity, EITC/IS/ACC Advanced Classical Cryptography, Message Authentication Codes, MAC (Message Authentication Codes) and HMAC, Examination review
What is the Z8X attack in the Elgamal digital signature scheme, and how does it allow an adversary to generate a valid signature without knowing the private key?
The Z8X attack is a known vulnerability in the Elgamal digital signature scheme that allows an adversary to generate a valid signature without knowledge of the private key. In order to understand this attack, it is important to have a clear understanding of the Elgamal digital signature scheme and its underlying mathematics. The Elgamal digital
How are addition and subtraction operations performed in Galois Fields?
In the field of classical cryptography, specifically in the context of the AES block cipher cryptosystem, Galois Fields (also known as finite fields) play a crucial role in performing addition and subtraction operations. Galois Fields are mathematical structures that are used to define the arithmetic operations within AES, providing a foundation for its cryptographic operations.
What is the Feistel network structure and how does it relate to DES?
The Feistel network structure is a symmetric encryption scheme that forms the basis for the Data Encryption Standard (DES), a widely used block cipher cryptosystem in classical cryptography. The Feistel network structure was introduced by Horst Feistel in the early 1970s and has since been adopted in various encryption algorithms due to its simplicity and
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, DES block cipher cryptosystem, Data Encryption Standard (DES) - Key schedule and decryption, Examination review
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