# Dennis Yurichev

by Dennis Yurichev

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## \[Crypto\] Time-based one-time password (TOTP) for 2FA, part II: YubiKey

DevFeed: [\[Crypto\] Time-based one-time password (TOTP) for 2FA, part II: YubiKey](<https://devfeed.tech/articles/crypto-time-based-one-time-password-totp-for-2fa-part-ii-yubikey-20551.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/TOTP2/>)

Published: 2026-09-13T22:00:00Z

Content type: article

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [passwords](<https://devfeed.tech/topics/passwords.md>), [Command-line interface](<https://devfeed.tech/topics/cli.md>), [Code](<https://devfeed.tech/topics/code.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Android](<https://devfeed.tech/topics/android.md>), [USB](<https://devfeed.tech/topics/usb.md>)

Tags: [android](<https://devfeed.tech/tags/android.md>), [code](<https://devfeed.tech/tags/code.md>), [command-line](<https://devfeed.tech/tags/command-line.md>), [linux](<https://devfeed.tech/tags/linux.md>), [password](<https://devfeed.tech/tags/password.md>), [secrets](<https://devfeed.tech/tags/secrets.md>), [usb](<https://devfeed.tech/tags/usb.md>)

### AI overview

The article examines using a YubiKey to store TOTP secrets for two-factor authentication. It explains that HMAC keys are intended to remain inside the device, but describes a Linux ykman weakness that could allow an attacker with temporary physical access to generate future TOTP keys and potentially log in during the relevant 30-second interval if the account password is also known.

### Source excerpt

[Crypto] Time-based one-time password (TOTP) for 2FA, part II: YubiKey

## \[Crypto\] Time-based one-time password (TOTP) for 2FA, part I

DevFeed: [\[Crypto\] Time-based one-time password (TOTP) for 2FA, part I](<https://devfeed.tech/articles/crypto-time-based-one-time-password-totp-for-2fa-part-i-20550.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/TOTP1/>)

Published: 2026-09-09T22:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [passwords](<https://devfeed.tech/topics/passwords.md>), [QR Code](<https://devfeed.tech/topics/qrcode.md>), [Google](<https://devfeed.tech/topics/google.md>), [Python](<https://devfeed.tech/topics/python.md>), [Unix](<https://devfeed.tech/topics/unix.md>), [App](<https://devfeed.tech/topics/app.md>), [email](<https://devfeed.tech/topics/email.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [account](<https://devfeed.tech/tags/account.md>), [app](<https://devfeed.tech/tags/app.md>), [argument](<https://devfeed.tech/tags/argument.md>), [backup](<https://devfeed.tech/tags/backup.md>), [code](<https://devfeed.tech/tags/code.md>), [crypto](<https://devfeed.tech/tags/crypto.md>), [env-file-security](<https://devfeed.tech/tags/env-file-security.md>), [github](<https://devfeed.tech/tags/github.md>), [google](<https://devfeed.tech/tags/google.md>), [password](<https://devfeed.tech/tags/password.md>), [protection](<https://devfeed.tech/tags/protection.md>), [python](<https://devfeed.tech/tags/python.md>), [run](<https://devfeed.tech/tags/run.md>), [server](<https://devfeed.tech/tags/server.md>), [smartphone](<https://devfeed.tech/tags/smartphone.md>), [unix](<https://devfeed.tech/tags/unix.md>)

### AI overview

This tutorial explains how time-based one-time passwords work for two-factor authentication. It covers importing a base32-encoded secret from a QR code into Google Authenticator, generating 6-digit login codes, and calculating them with HMAC-SHA-1 from the secret and Unix time. It also discusses backup codes and securely storing TOTP secrets separately from passwords.

### Source excerpt

[Crypto] Time-based one-time password (TOTP) for 2FA, part I

## Unpacking a database of unknown type

DevFeed: [Unpacking a database of unknown type](<https://devfeed.tech/articles/unpacking-a-database-of-unknown-type-20579.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/rutracker/>)

Published: 2026-06-29T22:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Database](<https://devfeed.tech/topics/database.md>), [Databases](<https://devfeed.tech/topics/databases.md>)

Tags: [blog-post](<https://devfeed.tech/tags/blog-post.md>), [database](<https://devfeed.tech/tags/database.md>)

### AI overview

A reverse-engineering tutorial explains how to unpack an unknown database file from an unofficial Rutracker dump. It identifies recurring markers in the file, extracts blocks, and uses 7z to unpack them, revealing HTML content from the Rutracker website.

### Source excerpt

Unpacking a database of unknown type

## Amateur cryptography: decrypting TVT CCTV camera config files

DevFeed: [Amateur cryptography: decrypting TVT CCTV camera config files](<https://devfeed.tech/articles/amateur-cryptography-decrypting-tvt-cctv-camera-config-files-20552.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/TVT/>)

Published: 2026-06-28T22:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Cryptography](<https://devfeed.tech/topics/cryptography.md>), [Encryption](<https://devfeed.tech/topics/encryption.md>)

Tags: [camera](<https://devfeed.tech/tags/camera.md>), [cryptography](<https://devfeed.tech/tags/cryptography.md>), [encryption](<https://devfeed.tech/tags/encryption.md>)

### AI overview

This article examines the decryption of TVT CCTV camera configuration files. It describes testing all 2-byte XOR keys, identifying the key 29 15, and observing that tabs and newlines remain unencrypted, preserving visual structure and allowing some encrypted files to be compared with diff tools.

### Source excerpt

Amateur cryptography: decrypting TVT CCTV camera config files

## Cracking simple XOR cipher with simulated annealing, part II

DevFeed: [Cracking simple XOR cipher with simulated annealing, part II](<https://devfeed.tech/articles/cracking-simple-xor-cipher-with-simulated-annealing-part-ii-20548.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/SA_XOR_nethack/>)

Published: 2026-06-21T22:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Encryption](<https://devfeed.tech/topics/encryption.md>), [Cryptography](<https://devfeed.tech/topics/cryptography.md>), [Script](<https://devfeed.tech/topics/script.md>)

Tags: [encryption](<https://devfeed.tech/tags/encryption.md>), [script](<https://devfeed.tech/tags/script.md>), [video](<https://devfeed.tech/tags/video.md>), [xor](<https://devfeed.tech/tags/xor.md>)

### AI overview

A technical blog post describes using simulated annealing to crack a simple XOR cipher found in NetHack's nhdat file. The author identifies a repeating five-character pattern, finds the XOR key, and confirms that the decrypted result is English text.

### Source excerpt

Cracking simple XOR cipher with simulated annealing, part II

## \[SMT\]\[Z3\] Predicting Math.random() in Firefox using Z3 SMT-solver

DevFeed: [\[SMT\]\[Z3\] Predicting Math.random() in Firefox using Z3 SMT-solver](<https://devfeed.tech/articles/smt-z3-predicting-math-random-in-firefox-using-z3-smt-solver-20590.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/xorshift/>)

Published: 2026-02-01T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Firefox](<https://devfeed.tech/topics/firefox.md>), [Code](<https://devfeed.tech/topics/code.md>), [math](<https://devfeed.tech/topics/math.md>), [C](<https://devfeed.tech/topics/c.md>)

Tags: [c](<https://devfeed.tech/tags/c.md>), [code](<https://devfeed.tech/tags/code.md>), [firefox](<https://devfeed.tech/tags/firefox.md>), [math](<https://devfeed.tech/tags/math.md>)

### AI overview

This tutorial shows how to use the Z3 SMT solver with Z3Py to recover the initial state of Firefox's Xorshift128+ pseudorandom number generator and predict Math.random() outputs. It explains why three generated real numbers are sufficient to determine the 128-bit state and demonstrates verification with C code.

### Source excerpt

[SMT][Z3] Predicting Math.random() in Firefox using Z3 SMT-solver

## \[Crypto\] Toy SSH client in ~2k SLOC of Python, v6

DevFeed: [\[Crypto\] Toy SSH client in ~2k SLOC of Python, v6](<https://devfeed.tech/articles/crypto-toy-ssh-client-in-2k-sloc-of-python-v6-20549.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/SSH6/>)

Published: 2026-01-19T23:00:00Z

Content type: release

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Python](<https://devfeed.tech/topics/python.md>), [ssh](<https://devfeed.tech/topics/ssh.md>), [client](<https://devfeed.tech/topics/client.md>)

Tags: [crypto](<https://devfeed.tech/tags/crypto.md>), [python](<https://devfeed.tech/tags/python.md>), [release](<https://devfeed.tech/tags/release.md>), [ssh](<https://devfeed.tech/tags/ssh.md>)

### AI overview

This release of a toy SSH client written in about 2,000 lines of Python fixes mostly network-related bugs. The project began as a learning exercise and became a practical tool for connecting to older routers and devices that use algorithms such as ssh-rsa and ssh-dss.

### Source excerpt

[Crypto] Toy SSH client in ~2k SLOC of Python, v6

## \[Math\]\[Pentesting\] Password requirements are harmful. A password with required digit/special character may be weaker. Part II.

DevFeed: [\[Math\]\[Pentesting\] Password requirements are harmful. A password with required digit/special character may be weaker. Part II.](<https://devfeed.tech/articles/math-pentesting-password-requirements-are-harmful-a-password-with-required-digit-special-character-may-be-weaker-part-ii-20574.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/password_req/>)

Published: 2026-01-11T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [passwords](<https://devfeed.tech/topics/passwords.md>), [math](<https://devfeed.tech/topics/math.md>)

Tags: [files](<https://devfeed.tech/tags/files.md>), [math](<https://devfeed.tech/tags/math.md>), [password](<https://devfeed.tech/tags/password.md>), [script](<https://devfeed.tech/tags/script.md>)

### AI overview

This article uses mathematical counting and scripts to examine password requirements for Dahua and Hikvision CCTV cameras. It argues that requiring digits or special characters can reduce the number of possible passwords, while noting that Hikvision's requirements produce a number close to the full set of possible eight-character passwords.

### Source excerpt

[Math][Pentesting] Password requirements are harmful. A password with required digit/special character may be weaker. Part II.

## \[RevEng\]\[CS\] Fuzzy topological sorting

DevFeed: [\[RevEng\]\[CS\] Fuzzy topological sorting](<https://devfeed.tech/articles/reveng-cs-fuzzy-topological-sorting-20562.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/fuzzy_topo_sort/>)

Published: 2026-01-08T23:00:00Z

Content type: article

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Sorting](<https://devfeed.tech/topics/sorting.md>), [Graphs](<https://devfeed.tech/topics/graphs.md>), [Algorithms](<https://devfeed.tech/topics/algorithms.md>), [C++](<https://devfeed.tech/topics/c-plus-plus.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Kernel](<https://devfeed.tech/topics/kernel.md>), [Terminal](<https://devfeed.tech/topics/terminal.md>)

Tags: [algorithms](<https://devfeed.tech/tags/algorithms.md>), [c-plus-plus](<https://devfeed.tech/tags/c-plus-plus.md>), [graphs](<https://devfeed.tech/tags/graphs.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [linux](<https://devfeed.tech/tags/linux.md>), [sorting](<https://devfeed.tech/tags/sorting.md>), [terminal](<https://devfeed.tech/tags/terminal.md>)

### AI overview

The article describes a fuzzy topological sorting method for graphs that may contain cycles. It uses simulated annealing to minimize backward references and maximize forward references, then applies the resulting ordering to call graphs from Linux 0.99.15 and the Boolector SMT solver to estimate function abstraction levels.

### Source excerpt

[RevEng][CS] Fuzzy topological sorting

## IOCCC/mullender revisited, position-independent code, shellcode

DevFeed: [IOCCC/mullender revisited, position-independent code, shellcode](<https://devfeed.tech/articles/ioccc-mullender-revisited-position-independent-code-shellcode-20545.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/PIC/>)

Published: 2026-01-04T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Assembly](<https://devfeed.tech/topics/assembly.md>), [Code](<https://devfeed.tech/topics/code.md>), [Programming](<https://devfeed.tech/topics/programming.md>), [Linux](<https://devfeed.tech/topics/linux.md>)

Tags: [assembly](<https://devfeed.tech/tags/assembly.md>), [code](<https://devfeed.tech/tags/code.md>), [linux](<https://devfeed.tech/tags/linux.md>), [programming](<https://devfeed.tech/tags/programming.md>)

### AI overview

This article revisits an IOCCC entry and explains position-independent code using arrays placed in executable sections. It demonstrates Linux x64 and ARM64 assembly examples, including shellcode-related syscall and PIC techniques, and describes code that can run across x64 and ARM64.

### Source excerpt

IOCCC/mullender revisited, position-independent code, shellcode

## \[RevEng\]\[x86\]\[x64\]\[C\]\[newbies\] Software reset in embedded devices

DevFeed: [\[RevEng\]\[x86\]\[x64\]\[C\]\[newbies\] Software reset in embedded devices](<https://devfeed.tech/articles/reveng-x86-x64-c-newbies-software-reset-in-embedded-devices-20578.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/reset/>)

Published: 2025-12-31T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [C](<https://devfeed.tech/topics/c.md>), [Embedded Software Dev](<https://devfeed.tech/topics/embedded-software-dev.md>), [Code](<https://devfeed.tech/topics/code.md>), [x86](<https://devfeed.tech/topics/x86.md>), [gcc](<https://devfeed.tech/topics/gcc.md>)

Tags: [blog-post](<https://devfeed.tech/tags/blog-post.md>), [c](<https://devfeed.tech/tags/c.md>), [code](<https://devfeed.tech/tags/code.md>), [compilation](<https://devfeed.tech/tags/compilation.md>), [embedded](<https://devfeed.tech/tags/embedded.md>), [embedded-devices](<https://devfeed.tech/tags/embedded-devices.md>), [gcc](<https://devfeed.tech/tags/gcc.md>), [software](<https://devfeed.tech/tags/software.md>), [x86](<https://devfeed.tech/tags/x86.md>)

### AI overview

This tutorial explains a software-reset technique for embedded devices using pure C. It shows how calling a function pointer at address zero can jump to firmware on systems that start execution there after power-on or reset, and discusses the behavior of the stack and local variables.

### Source excerpt

[RevEng][x86][x64][C][newbies] Software reset in embedded devices

## Testing word counting code using KLEE and CBMC

DevFeed: [Testing word counting code using KLEE and CBMC](<https://devfeed.tech/articles/testing-word-counting-code-using-klee-and-cbmc-20586.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/wc/>)

Published: 2025-12-24T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Testing](<https://devfeed.tech/topics/testing.md>), [C](<https://devfeed.tech/topics/c.md>), [Code](<https://devfeed.tech/topics/code.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Unix](<https://devfeed.tech/topics/unix.md>)

Tags: [c](<https://devfeed.tech/tags/c.md>), [code](<https://devfeed.tech/tags/code.md>), [linux](<https://devfeed.tech/tags/linux.md>), [testing](<https://devfeed.tech/tags/testing.md>), [unix](<https://devfeed.tech/tags/unix.md>), [verification](<https://devfeed.tech/tags/verification.md>)

### AI overview

This article examines a rewritten word-counting exercise from The C Programming Language using buffer input instead of console input. It compares behavior involving zero bytes, whitespace, isolated words, and buffer limits with Linux's wc and the original Unix utility, then discusses verification with CBMC and KLEE and the feasibility of brute-force testing.

### Source excerpt

Testing word counting code using KLEE and CBMC

## \[Math\] Intervals: examples of open intervals; fencepost errors

DevFeed: [\[Math\] Intervals: examples of open intervals; fencepost errors](<https://devfeed.tech/articles/math-intervals-examples-of-open-intervals-fencepost-errors-20567.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/intervals_open_fence/>)

Published: 2025-12-18T23:00:00Z

Content type: article

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [math](<https://devfeed.tech/topics/math.md>), [Programming](<https://devfeed.tech/topics/programming.md>)

Tags: [errors](<https://devfeed.tech/tags/errors.md>), [examples](<https://devfeed.tech/tags/examples.md>), [math](<https://devfeed.tech/tags/math.md>), [programming](<https://devfeed.tech/tags/programming.md>)

### AI overview

This article explains open, closed, and half-open intervals in programming, using divisor ranges and loop boundaries to illustrate how confusion between interval types causes fencepost errors. It also notes Dijkstra's advocacy of half-open intervals and zero-based arrays.

### Source excerpt

[Math] Intervals: examples of open intervals; fencepost errors

## \[Math\] Intervals: Apache Maven version numbers

DevFeed: [\[Math\] Intervals: Apache Maven version numbers](<https://devfeed.tech/articles/math-intervals-apache-maven-version-numbers-20566.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/intervals_maven/>)

Published: 2025-12-18T23:00:00Z

Content type: article

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Maven](<https://devfeed.tech/topics/maven.md>), [math](<https://devfeed.tech/topics/math.md>)

Tags: [apache](<https://devfeed.tech/tags/apache.md>), [math](<https://devfeed.tech/tags/math.md>), [numbers](<https://devfeed.tech/tags/numbers.md>)

### AI overview

This article explains how Apache Maven version ranges use mathematical interval notation, including fixed versions, half-open intervals, half-closed intervals, and omitted infinity signs.

### Source excerpt

[Math] Intervals: Apache Maven version numbers

## \[Pentesting\]\[Math\] Bruteforce passwords using cartesian product

DevFeed: [\[Pentesting\]\[Math\] Bruteforce passwords using cartesian product](<https://devfeed.tech/articles/pentesting-math-bruteforce-passwords-using-cartesian-product-20556.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/cartesian/>)

Published: 2025-12-17T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [math](<https://devfeed.tech/topics/math.md>), [passwords](<https://devfeed.tech/topics/passwords.md>), [Python](<https://devfeed.tech/topics/python.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [code](<https://devfeed.tech/tags/code.md>), [examples](<https://devfeed.tech/tags/examples.md>), [passwords](<https://devfeed.tech/tags/passwords.md>), [python](<https://devfeed.tech/tags/python.md>)

### AI overview

This tutorial explains how Python's itertools.product can enumerate password combinations by forming Cartesian products over character sets. It also notes that generating all username-and-password combinations is a Cartesian product of those sets.

### Source excerpt

[Pentesting][Math] Bruteforce passwords using cartesian product

## \[Math\] Intervals: examples of half-open intervals

DevFeed: [\[Math\] Intervals: examples of half-open intervals](<https://devfeed.tech/articles/math-intervals-examples-of-half-open-intervals-20565.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/intervals_half_open/>)

Published: 2025-12-17T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [math](<https://devfeed.tech/topics/math.md>), [Programming](<https://devfeed.tech/topics/programming.md>), [C](<https://devfeed.tech/topics/c.md>), [C++](<https://devfeed.tech/topics/c-plus-plus.md>), [Java](<https://devfeed.tech/topics/java.md>), [Python](<https://devfeed.tech/topics/python.md>)

Tags: [c](<https://devfeed.tech/tags/c.md>), [c-plus-plus](<https://devfeed.tech/tags/c-plus-plus.md>), [examples](<https://devfeed.tech/tags/examples.md>), [java](<https://devfeed.tech/tags/java.md>), [math](<https://devfeed.tech/tags/math.md>), [programming](<https://devfeed.tech/tags/programming.md>), [python](<https://devfeed.tech/tags/python.md>)

### AI overview

The article explains half-open intervals, written as [begin, end), where the end value is excluded. It gives programming examples, including Python's range(start, stop) and loop conventions in C, C++, Java, and other languages.

### Source excerpt

[Math] Intervals: examples of half-open intervals

## \[Math\] Intervals: examples of closed intervals

DevFeed: [\[Math\] Intervals: examples of closed intervals](<https://devfeed.tech/articles/math-intervals-examples-of-closed-intervals-20564.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/intervals_closed/>)

Published: 2025-12-17T23:00:00Z

Content type: article

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [math](<https://devfeed.tech/topics/math.md>), [Mathematics](<https://devfeed.tech/topics/mathematics.md>)

Tags: [examples](<https://devfeed.tech/tags/examples.md>), [math](<https://devfeed.tech/tags/math.md>)

### AI overview

An examples-focused explanation of closed intervals, including their inclusive notation and uses in mathematics, Wolfram Mathematica, Fortran, algorithms, Unix shell patterns, rounded ratings, and everyday ranges.

### Source excerpt

[Math] Intervals: examples of closed intervals

## \[Pentesting\]\[Math\] Finding masks for Hashcat using combinatorics

DevFeed: [\[Pentesting\]\[Math\] Finding masks for Hashcat using combinatorics](<https://devfeed.tech/articles/pentesting-math-finding-masks-for-hashcat-using-combinatorics-20563.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/hashcat_masks/>)

Published: 2025-12-14T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [math](<https://devfeed.tech/topics/math.md>), [passwords](<https://devfeed.tech/topics/passwords.md>)

Tags: [commands](<https://devfeed.tech/tags/commands.md>), [math](<https://devfeed.tech/tags/math.md>), [passwords](<https://devfeed.tech/tags/passwords.md>)

### AI overview

This article uses combinatorics to analyze common password masks in rockyou password lists. It presents masks and Hashcat commands, including those estimated to run in under one month on an RTX 4000 Ada in WPA2 cracking mode.

### Source excerpt

[Pentesting][Math] Finding masks for Hashcat using combinatorics

## What is MQTT (IoT, smart homes) --- an explanation under 120 lines or 1100 words

DevFeed: [What is MQTT (IoT, smart homes) --- an explanation under 120 lines or 1100 words](<https://devfeed.tech/articles/what-is-mqtt-iot-smart-homes-an-explanation-under-120-lines-or-1100-words-20572.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/mqtt/>)

Published: 2025-12-10T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [MQTT](<https://devfeed.tech/topics/mqtt.md>), [Internet of things](<https://devfeed.tech/topics/iot.md>), [Networks](<https://devfeed.tech/topics/networks.md>), [IRC](<https://devfeed.tech/topics/irc.md>)

Tags: [homes](<https://devfeed.tech/tags/homes.md>), [iot](<https://devfeed.tech/tags/iot.md>), [irc](<https://devfeed.tech/tags/irc.md>), [mqtt](<https://devfeed.tech/tags/mqtt.md>), [networks](<https://devfeed.tech/tags/networks.md>), [smart](<https://devfeed.tech/tags/smart.md>)

### AI overview

An introductory article about MQTT in the context of IoT and smart homes. The supplied text begins by tracing the history of networked chat from multiplayer text games to IRC, Discord, and related messaging systems, but it does not include a substantive explanation of MQTT mechanics in the available excerpt.

### Source excerpt

What is MQTT (IoT, smart homes) --- an explanation under 120 lines or 1100 words

## \[Math\] Number of ways to insert 4 wires into 8-pin 8P8C Ethernet connector

DevFeed: [\[Math\] Number of ways to insert 4 wires into 8-pin 8P8C Ethernet connector](<https://devfeed.tech/articles/math-number-of-ways-to-insert-4-wires-into-8-pin-8p8c-ethernet-connector-20559.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/ethernet/>)

Published: 2025-12-08T23:00:00Z

Content type: article

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Ethernet](<https://devfeed.tech/topics/ethernet.md>), [math](<https://devfeed.tech/topics/math.md>)

Tags: [ethernet](<https://devfeed.tech/tags/ethernet.md>), [math](<https://devfeed.tech/tags/math.md>)

### AI overview

This article uses combinatorics to count ways of inserting four wires into an 8-pin 8P8C Ethernet connector and connecting two such connectors. It gives counts of 24 permutations for known Ethernet pins, 70 choices when the pin positions are unknown, and 117,600 possible connections using four wires.

### Source excerpt

[Math] Number of ways to insert 4 wires into 8-pin 8P8C Ethernet connector

## \[Unix\]\[C\] Similarities between Unix symlinks and C/C++ pointers/references

DevFeed: [\[Unix\]\[C\] Similarities between Unix symlinks and C/C++ pointers/references](<https://devfeed.tech/articles/unix-c-similarities-between-unix-symlinks-and-c-c-pointers-references-20581.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/symlink/>)

Published: 2025-12-03T23:00:00Z

Content type: comparison

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [Unix](<https://devfeed.tech/topics/unix.md>), [C](<https://devfeed.tech/topics/c.md>), [C++](<https://devfeed.tech/topics/c-plus-plus.md>), [Programming](<https://devfeed.tech/topics/programming.md>)

Tags: [blog-post](<https://devfeed.tech/tags/blog-post.md>), [c](<https://devfeed.tech/tags/c.md>), [c-plus-plus](<https://devfeed.tech/tags/c-plus-plus.md>), [unix](<https://devfeed.tech/tags/unix.md>)

### AI overview

This article compares Unix symbolic links with C and C++ pointers and references. It explains the analogy between copying a symlink and dereferencing it, and between copying a pointer and copying the referenced object.

### Source excerpt

[Unix][C] Similarities between Unix symlinks and C/C++ pointers/references

## Analysis of Dahua CCTV Camera Authentication

DevFeed: [Analysis of Dahua CCTV Camera Authentication](<https://devfeed.tech/articles/pentesting-dahua-cctv-cameras-auth-20557.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/dahua/>)

Published: 2025-12-01T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [webcam](<https://devfeed.tech/topics/webcam.md>), [hash](<https://devfeed.tech/topics/hash.md>), [Python](<https://devfeed.tech/topics/python.md>)

Tags: [auth](<https://devfeed.tech/tags/auth.md>), [camera](<https://devfeed.tech/tags/camera.md>), [hash](<https://devfeed.tech/tags/hash.md>), [python](<https://devfeed.tech/tags/python.md>), [tcp](<https://devfeed.tech/tags/tcp.md>)

### AI overview

A pentesting-oriented analysis of Dahua CCTV camera authentication over its proprietary TCP protocol. It describes a fake Python server used to observe a camera login and presents the known portion of the hash calculation, while noting that the remaining 16 bytes are not understood and no Hashcat workflow was found.

### Source excerpt

[Pentesting] Dahua (CCTV cameras) auth

## \[Pentesting\] ONVIF (CCTV cameras) auth

DevFeed: [\[Pentesting\] ONVIF (CCTV cameras) auth](<https://devfeed.tech/articles/pentesting-onvif-cctv-cameras-auth-20544.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/ONVIF/>)

Published: 2025-11-27T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [passwords](<https://devfeed.tech/topics/passwords.md>), [XML](<https://devfeed.tech/topics/xml.md>), [Python](<https://devfeed.tech/topics/python.md>)

Tags: [auth](<https://devfeed.tech/tags/auth.md>), [camera](<https://devfeed.tech/tags/camera.md>), [cameras](<https://devfeed.tech/tags/cameras.md>), [password](<https://devfeed.tech/tags/password.md>), [python](<https://devfeed.tech/tags/python.md>), [tcp](<https://devfeed.tech/tags/tcp.md>), [xml](<https://devfeed.tech/tags/xml.md>)

### AI overview

This article examines ONVIF authentication for CCTV cameras over TCP. It explains the username, password digest, nonce, and date fields, gives the digest calculation, and describes using Hashcat to crack a known password digest.

### Source excerpt

[Pentesting] ONVIF (CCTV cameras) auth

## \[Pentesting\] RTSP (CCTV cameras) auth

DevFeed: [\[Pentesting\] RTSP (CCTV cameras) auth](<https://devfeed.tech/articles/pentesting-rtsp-cctv-cameras-auth-20546.md>)

Original publisher: [Read original article](<https://yurichev.com/blog/RTSP_auth/>)

Published: 2025-11-23T23:00:00Z

Content type: tutorial

Language: en

Sources: [Dennis Yurichev](<https://devfeed.tech/sources/dennis-yurichev.md>)

Topics: [passwords](<https://devfeed.tech/topics/passwords.md>), [HTTP](<https://devfeed.tech/topics/http.md>), [TLS (Transport Layer Security)](<https://devfeed.tech/topics/tls.md>), [SSL](<https://devfeed.tech/topics/ssl.md>), [Python](<https://devfeed.tech/topics/python.md>)

Tags: [auth](<https://devfeed.tech/tags/auth.md>), [hash](<https://devfeed.tech/tags/hash.md>), [http](<https://devfeed.tech/tags/http.md>), [passwords](<https://devfeed.tech/tags/passwords.md>), [python](<https://devfeed.tech/tags/python.md>), [ssl](<https://devfeed.tech/tags/ssl.md>), [tls](<https://devfeed.tech/tags/tls.md>)

### AI overview

A pentesting article examines authentication in RTSP CCTV camera streams, comparing basic and digest authentication. It demonstrates how ARP spoofing and captured exchanges can enable password enumeration or cracking, and recommends firmware updates, strong passwords, and SSL/TLS.

### Source excerpt

[Pentesting] RTSP (CCTV cameras) auth

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