BeeOS is a FOSS UNIX-like operating system focused on simplicity and POSIX compliance. The overall system is composed by four subprojects: The C standard library (libc) A utility user-space library (libu) Some user space applications (user) The kernel (kernel) This analysis targets the BeeOS kernel component
The Basic Encoding Rules for ASN.1 (BER) give one or more ways to represent any ASN.1 value as an octets sequence. There are three methods to encode an ASN.1 value under BER, the choice of which depends on the type of value and whether the length of the value is known.
2017-11-07 | #cryptography
Feistel ciphers are a family of symmetric encryption algorithms that use repeated rounds of substitution and permutation operations on blocks of data to provide confidentiality and data integrity. Popular examples of Feistel ciphers include:
The following article is highly inspired by the work of Will Dietz, Peng Li, John Regehr, and Vikram Adve: ‘Understanding Integer Overflow in C/C++’. The work has been sliced down to the core and amended with some notes.
The Chinese Remainder Theorem (CRT) is a mathematical theorem that provides a way to solve a system of linear congruences. Specifically, it states that given a set of integers that are pairwise coprime and a set of remainders modulo those integers, there exists a unique solution, modulo the product of the integers, to the system of congruences.
2017-09-25 | #cryptography
Trivial Attempt Let’s first try to build a scheme directly using the Fermat’s Little Theorem. Given a prime number p and a message m < p, we choose two numbers e and d such that e·d = 1 (mod p-1).
Given a natural number n, the Euler φ function, also known as Euler’s Totient, applied to n represents the number of positive numbers less than n that are coprime to n.
2017-07-28 | #mathematics
A curated selection of essential mathematical symbols I found useful form my daily tasks. From calculus to greek letters. ∑ymbols ∫f Μath: ∀ ∃ ⊂🧮 ∩𝛍∀ ∑Σ, ♇𝛆Δ⇒⊢ ∃∀⇔ 𝛈𝜆𝛀⊆ ✍️🔢 ∃⇑ ∑𝚄𝚗𝚒𝚌𝚘𝚍𝚎’𝚜 ℝ𝕖⇧⊇📈 𝕋⊂⊆∈🔢
Fermat’s Little theorem states that if p is a prime number and a is an integer not divisible by p, then a^(p-1) ≡ 1 (mod p). Euler’s theorem extends this to any positive integer n, stating that a^φ(n) ≡ 1 (mod n), where φ(n) is Euler’s totient function.
Introduction GnuPG is a hybrid-encryption software program because it uses a combination of conventional symmetric-key cryptography for speed, and public-key cryptography for ease of secure key exchange, typically by using the recipient’s public key to encrypt a session key which is used only once.