Secure private shard infrastructure lets you protect your data while leveraging all the business benefits of open-source blockchains. Calimero offers its Console as a product. Console is a shard configuration interface that enables you to develop, test and deploy your private shard in a matter of minutes. A perfect way to accelerate your business with this out-of-the-box solution. But highly customizable at the same time. The private shard tech stack offers drastical improvements to a business by moving part (or the entirety) of operations to a private shard. Offering an impressive tech stack of console (interface), bridge (to communicate between private shards and a public network), privacy features to protect the data on the permissioned private network, and a drastic gas cost reduction by essentially making the private shard gas fees ZERO. Connect to private or public blockchain applications like DeFi, NFTs, on-chain KYC, and more without any compromise on confidentiality and privacy. You control who has the access to which data. Other benefits: - Giving you all the benefits of NEAR in terms of technology and security, but on your own subnetwork, independent from public validators. - Interoperable with other enterprises, shards, and public blockchain. - Designed to support confidential native NEAR WASM and Aurora EVM smart contracts. - Customizable block times, contract sizes and gas limits. - Bridging the data between the shard and the mainnet is extremely fast (5sec). - Predictable costs. Plan out your budget ahead of time by having access to the pricing tiers.

Calimero

(Scroll down to the hack) ‘Lying’ by Sam Harris explores why we lie to one another. Is someone with makeup lying to us about their appearance? We’ve all been Seinfeld & Aziz at the restaurant. And we do it because lying is easier. The social scientist will point out ☝️the effort vs benefit of ethical responsibility is too high☝️ And so, we shouldn’t be surprised that our users lie to us. It’s what makes listening to users an underrated skill. Most times, we don’t even intend to lie. We just forget to think about the truth. We fall prey to biases and tricks that the mind plays on us. Like the availability bias. Someone asks us “What’s keeping you up at night?” and we blurt out the first thing our minds make available to us. Not a great question to ask. By the way, congratulations if you’re already talking to users. Having spent hundreds of hours doing it at multiple ventures, I can tell you’re already. Most people don’t even do it. People don’t talk to users for a variety of reasons. It’s uncomfortable. You’re troubling someone. You need to say please and thank you. It’s scary. You may mess it up. You’re thinking about what to ask next. And not listening to what they’re saying. As such, many organizations and individuals hide behind surveys, or just read support tickets and data. Others justify different priorities, or.. just look busy. Hack Question (HQ) Get started on a call today by simply asking the user this again and again “And what did you do next?” Some theory and nuance follow, but if you want to skip it and hop on a call, just go on try it! It’s a Hack question for a reason It helps recall vs reimagine: We’re terrible at reimagining others’ worlds. “If I cooked up some tapioca balls and put them in tea would you drink it?” Err… sure! It’s open vs close-ended: Asking close-ended questions isn’t useful. It allows the easy way out. “How is everything?” Great! It’s non-leading vs leading: Leading questions make it easy for someone to lie. “This recipe is from my grandmother, isn’t it amazing” Yes! It forces detail: Building products is a high detail activity. Simply knowing “world hunger is a problem” doesn’t help you decide what to cook next. It uncovers jobs to be done: Every successful product solves some job. This question forces the user to recall jobs they need to do to accomplish a goal. Meeting bookends You naturally don’t want to start and finish the call with a Hack question. So, what do bookends look like? Smile, thank, and welcome your guest. Let them know it isn’t an inquisition. You’re just trying to understand better. Ok to record? Intro: Ask exactly what your product intends to solve. Remember we’re going for detail. Kickoff: “Tell me about the last time you bought steak at a food truck”. Depending on their response, adjust, but . They may be further up the buyer journey. That’s ok, you’ll get different information from this audience. Like how to acquire them. settle into HQ asap Speak from the heart. Big thank you, it was a valuable conversation and meant a lot. Finish: a BANTer s you get better at it You’ve overcome the initial fear. Now learn to BANTer between HQs as they describe pain points. Budget: Have you spent money on solving that? Authority: Did you need to get an ok from someone else first? Need: Do you really need to solve it, how many hrs/week do you get back? Timing: When was the last time you faced this, how often do you face it? It’s a sales discovery technique but applies to feature discovery too. Not every pain point is worth solving. Uncover the one to focus on. Don’t panic, and good luck! 😅

Hack Calmer Conversations and Get Reliable Feedback from Users

I am a 🇵🇹 PhD researcher @ Técnico Lisboa, where I teach User Centered Design. I am being a mentor at the Hyperledger Fabric Based Access Control project, supported and funded by Hyperledger and the Linux Foundation 🔥. 🚀 💪 Please make sure to check my blockchain projects on my Github sponsors  page ⛓️ Testing blockchain applications can be cumbersome, mainly because they are complex, resource-demanding distributed systems. Testing your blockchain app on the cloud might improve the efficiency of the testing process, as well as achieving more realistic test environments. 302665) applies , , , and more to come) This article provides a 101 guide on how to use Hyperledger Caliper (commit on Google Cloud , tackling the scenario of testing a Hyperledger Composer application, a blockchain framework which facilitates the development of Hyperledger Fabric applications. Nonetheless, this testing process to all blockchains supported by Hyperledger Caliper ( Hyperledger Burrow Hyperledger Fabric Hyperledger Iroha Hyperledger Sawtooth . Setting Up The Testing Environment Create a private repository (e.g., on Github).Fork the Hyperledger Caliper project to your private repo: 1. Create a private repository (e.g., on Github). 2.Fork the Hyperledger Caliper project to your private repo: git clone --bare https: cd caliper.git
git push --mirror https: cd ..
rm -rf caliper.git //github.com/hyperledger/caliper.git //github.com/USERNAME/CALIPER-PRIVATE-REPO.git 3. Clone your private repo: git clone https: //github.com/USERNAME/CALIPER-PRIVATE-REPO.git 4. On , create a folder with the name of your application, e.g. . CALIPER-PRIVATE-REPO/packages/caliper-samples/benchmark/composer my-network 5. On the folder, paste the contents of the . On a future article, I will explain how to write tests ( ) and benchmark configurations ( ). my-network configuration and test files from this repository my-network.js config.yaml 6. You should have a developed business network using Composer (the BNA archive). If you have not developed a business network, you can still configure Caliper to test default business networks. On , create a folder named . Paste your business network archive files ( BNA file) inside the folder. You should have a lib folder, a models folder, and the files package.json, permission.acl and optionally, a README.md. CALIPER-PRIVATE-REPO-justicechain/packages/caliper-samples/src/contract/composer my-network decompressed jsonNote that on package.json, the name and version of the network have to coincide with the one on composer.json. Example package.json: { :{ : }, : , : ,
 
 ... ETC "engines" "composer" "^0.20.0" "name" "my-network" "version" "0.2.6-deploy.1" 7. You have the necessary files to test your app. Push them to your repository: git add *
git commit -m git push origin master "add benchmark files" Setting Up Google Cloud 1. Create an account on Google Cloud. New accounts can apply for a free trial grant. Create a project, and activate the Compute Instance API. 2. At Compute Engine -> VM Instances, click on . Create a new instance 3. Start your instance. 4. Click on Connect — SSH. 5. Install the prerequisites for Hyperledger Caliper (thanks ): Daz Wilkin sudo apt-get update
sudo apt-get install \
    linux-image-extra-$(uname -r) \
    linux-image-extra-virtual
sudo apt-get update
sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common
curl -fsSL https: sudo add-apt-repository \ sudo apt-get update
sudo apt-get install docker-ce
sudo usermod -aG docker $USER
sudo systemctl enable docker
docker --version //download.docker.com/linux/ubuntu/gpg | sudo apt-key add - "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable" sudo curl -L https: sudo chmod +x /usr/local/bin/docker-compose
Golang (optional)
VERSION= OS=linux
ARCH=amd64
sudo curl \
--location https: --output go$VERSION.$OS-$ARCH.tar.gz
sudo tar -C /usr/local -xzf go$VERSION.$OS-$ARCH.tar.gz PATH=$PATH: local/go/bin
go version //github.com/docker/compose/releases/download/1.16.1/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose 1.9 .1 //golang.org/dl/go$VERSION.$OS-$ARCH.tar.gz \ export /usr/ 6. Clone your private repository with Caliper and your blockchain app to your Google Compute instance. Testing your Application To run your benchmark, navigate to caliper/packages/caliper-samples. To benchmark your application with run: caliper benchmark run -w ./ -c benchmark/composer/justice/config.yaml -n benchmark/composer/justice/composer.json CouchDB To benchmark your application with run: caliper benchmark run -w ./ -c benchmark/composer/justice/config.yaml -n benchmark/composer/justice/composer-level.json LevelDB The results of the benchmark will be reported on the terminal. Do not forget to stop your machines in Google Cloud after finishing the experiments or else 💸. Next Steps Thanks very much for reading. You Rock 💪. 🚀 🙏 If you like blockchain and open source, be sure to support my work on Github sponsors  page

Test Your Blockchain On Google Cloud Using Hyperledger Caliper [A How To Guide]

Episode 27 of the : An interview with , Chairman and Co-Founder of , and co-creator of Kodak Coin. Hacker Noon Podcast Cameron Chell ICOx Innovations Today’s show would not be possible without Digital Ocean . Listen to the interview on , or , or watch on . iTunes Google Podcast YouTube In this episode and discuss bringing blockchain technology to enterprise companies we already know and trust, and what it is going to take to move from centralized systems to decentralized systems. Trent Lapinski Cameron Chell “Our thinking, yet to be proven, is that we go to these established brands who are already transacting in tens or hundreds of millions of dollars in revenue and they can utilize a coin or the crypto infrastructure that can either reduce their costs or increase customer attraction.” “Ultimately, society and certainly all economics run on trust, there is no other currency other than trust. When you have a system that can replace trust or create an environment where you can transact in a trustless way, the impact globally to me is beyond measure.” — Cameron Chell _Episode 27 of the Hacker Noon Podcast: An interview with Cameron Chell, Chairman and Co-Founder of ICOx Innovations…_www.podbean.com Building The Impossible via Business Acceleration with Cameron Chell P.S. If you dig the new Hacker Noon Podcast , consider giving us a 5 star review on iTunes. Today’s show would not be possible without Digital Ocean . Learn more at do.co/hackernoon . Also check out , and . February top stories the latest stories today’s homepage

Building The Impossible via Business Acceleration with Cameron Chell

I’m 32 and spent $200k on biohacking. Became calmer, thinner, extroverted, healthier & happier.

Tengo 32 años y gasté $200k en biohacking. Se volvió más tranquilo, más delgado, extrovertido, más saludable y más feliz.

Object-oriented programming (OOP) is a programming model that organizes software around objects(data) and object manipulation. OOP’s use of objects helps to break complex problems into smaller manageable parts, thus making code more straightforward to comprehend and manage, providing developers with a sense of ease.  Over the next few minutes, we will go over the following core concepts as they relate to OOP: Class


Object


Encapsulation


Inheritance


Polymorphism


Association 📓 All upcoming examples will use python code Class a class is a template used to create objects. Classes define the attributes of objects and the methods that the class instances will share. class Parent:
    def __init__(self, name, hair_color):
        self.name = name
        self.hair_color= hair_color

    def description(self):
        print(f"I'm {self.name}, my hair is {self.hair_color}!") The above snippet creates a class named Parent, which contains attributes, name and hair_color and a method, description(). Every instance of the class will have the same attributes and methods. Object Regarding OOP, an object is an instance of a class. It has attributes and can perform actions defined by its class. The following example creates instances of the Parent class; once they have been created, we can access its publicly available attributes. For example, father.hair_color returns a value of Red. father= Parent("Dylan", "Red")
mother= Parent("Grace", "Brown")

father.hair_color # Red
mother.hair_color # Brown Encapsulation Encapsulation bundles attributes and methods within a class and can restrict access to some of the object’s components. For example, the code below defines a Parent class. The class has three attributes: name, hair_color, and __age. The name and hair_color attributes are publicly accessible; however, calling the __age attribute will result in an AttributeError. The double underscore causes an attribute to become private. To get the value of the __age attribute, the get_age() method must be called, as it will return the age attribute given to the Parent. class Parent:
    def __init__(self, name, hair_color, age):
        self.name = name
        self.hair_color= hair_color
        self.__age= age

    def description(self):
        print(f"I'm {self.name}, my hair is {self.hair_color}!") 

    def get_age(self):
        return self.__age

father= Parent("Dylan", "Red", 45)

father.name # Dylan
father.__age# will result in an AttributeError
father.get_age() # 45
father.description() # I'm Dylan, my hair color is Red! Inheritance 👀 ignore super().description() in the following example. We’ll go over this once we get to Polymorphism Inheritance occurs when a class inherits the attributes and methods of another class. In the following example, the Child class inherits the same attributes as the Parent class while creating its own unrelated attributes. class Child(Parent):
    def __init__( self, name, hair_color, age, major):
        super().__init__(name, hair_color, age)
        self.major = major

    def description(self):
        super().description()
        print(f"Name: {self.name}")
        print(f"Hair Color: {self.get_hair_color()")
        print(f"Age: {self.get_age()}")
        print(f"Major: {self.major}")

child = Child("Dwight", "Auburn", 20, "Computer Science")
child.description()
#Output
# I'm Dwight, my hair color is Auburn!
# Name: Dwight
# Hair Color: Auburn
# Age: 20
# Major: "Computer Science Polymorphism Polymorphism  allows you to override or modify class methods in subclasses. As seen in the previous snippet on Inheritance, the Child class adapts and modifies the Parent method description(). By including the super().description() within the description() method, you can adapt the inclusion of the Parent output into the Child’s description() method output. In the next snippet, the Child class inherits the attributes of the Parent class but overrides the description() method, resulting in a different output. class Child(Parent):
    def __init__(self, name, hair_color, age, major):
        super().__init__(name, hair_color, age)
        self.major = major

    def description(self):
        print(f"Hello my name is {self.name}, I'm {self.get_age()} and I major in {self.major}!")

parent = Parent("Charles", "Grey", 45)
child = Child("Dwight", "Auburn", 20, "Computer Science")
parent.description()
#Output
# I'm Charles, my hair color is Grey!

child.description()
# Hello my name is Dwight, I'm 20 and I major in Computer Science! Association Association in programming is versatile, as it can be one-to-one, one-to-many, or many-to-many. It refers to the relationship between two classes where one class uses another. In the following example, we will use a one-to-many relation between classes. The Parent class can have many children, and we can add multiple Child instances via the add_child() method. class Parent:
    def __init__(self, name):
        self.name = name
        self.children = []

    def add_child(self, child):
        self.children.append(child)

    def list_children(self):
        return [child.name for child in self.children]

    def number_of_children(self):
        if not self.children:
            return "No children"
        return len(self.children)

class Child:
    def __init__(self, name, age):
        self.name = name
        self.age = age

parent = Parent("James")
child1 = Child("James Jr.", 12)
child2 = Child("Cameron", 16)

parent.add_child(child1)
parent.add_child(child2)

# List Children
for child in parent.list_children():
    print(child)

# James Jr.
# Cameron

parent.number_of_children()

# 2 Conclusion Object-oriented programming (OOP) offers a robust framework for developing modular, reusable, and maintainable code. Its foundational concepts, such as classes, objects, encapsulation, inheritance, polymorphism, and association, enable developers to create scalable and efficient software solutions. This efficiency makes OOP an indispensable paradigm in modern programming. Embracing OOP enhances code organization and facilitates easier debugging and future-proofing of applications, making developers more productive and effective. Object-oriented programming (OOP) is a programming model that organizes software around objects(data) and object manipulation. OOP’s use of objects helps to break complex problems into smaller manageable parts, thus making code more straightforward to comprehend and manage, providing developers with a sense of ease.  Over the next few minutes, we will go over the following core concepts as they relate to OOP: Class Object Encapsulation Inheritance Polymorphism Association Class Class Object Object Encapsulation Encapsulation Inheritance Inheritance Polymorphism Polymorphism Association Association 📓 All upcoming examples will use python code 📓 All upcoming examples will use python code Class a class is a template used to create objects. Classes define the attributes of objects and the methods that the class instances will share. class Parent:
    def __init__(self, name, hair_color):
        self.name = name
        self.hair_color= hair_color

    def description(self):
        print(f"I'm {self.name}, my hair is {self.hair_color}!") class Parent:
    def __init__(self, name, hair_color):
        self.name = name
        self.hair_color= hair_color

    def description(self):
        print(f"I'm {self.name}, my hair is {self.hair_color}!") The above snippet creates a class named Parent , which contains attributes, name and hair_color and a method, description() . Every instance of the class will have the same attributes and methods. Parent name hair_color description() Object Regarding OOP, an object is an instance of a class. It has attributes and can perform actions defined by its class. The following example creates instances of the Parent class; once they have been created, we can access its publicly available attributes. For example, father.hair_color returns a value of Red . Parent father.hair_color Red father= Parent("Dylan", "Red")
mother= Parent("Grace", "Brown")

father.hair_color # Red
mother.hair_color # Brown father= Parent("Dylan", "Red")
mother= Parent("Grace", "Brown")

father.hair_color # Red
mother.hair_color # Brown Encapsulation Encapsulation bundles attributes and methods within a class and can restrict access to some of the object’s components. For example, the code below defines a Parent class. The class has three attributes: name , hair_color , and __age . The name and hair_color attributes are publicly accessible; however, calling the __age attribute will result in an AttributeError. The double underscore causes an attribute to become private. To get the value of the __age attribute, the get_age() method must be called, as it will return the age attribute given to the Parent . Parent name hair_color __age name hair_color __age __age get_age() Parent class Parent:
    def __init__(self, name, hair_color, age):
        self.name = name
        self.hair_color= hair_color
        self.__age= age

    def description(self):
        print(f"I'm {self.name}, my hair is {self.hair_color}!") 

    def get_age(self):
        return self.__age

father= Parent("Dylan", "Red", 45)

father.name # Dylan
father.__age# will result in an AttributeError
father.get_age() # 45
father.description() # I'm Dylan, my hair color is Red! class Parent:
    def __init__(self, name, hair_color, age):
        self.name = name
        self.hair_color= hair_color
        self.__age= age

    def description(self):
        print(f"I'm {self.name}, my hair is {self.hair_color}!") 

    def get_age(self):
        return self.__age

father= Parent("Dylan", "Red", 45)

father.name # Dylan
father.__age# will result in an AttributeError
father.get_age() # 45
father.description() # I'm Dylan, my hair color is Red! Inheritance 👀 ignore super().description() in the following example. We’ll go over this once we get to Polymorphism 👀 ignore super().description() in the following example. We’ll go over this once we get to Polymorphism super().description() Inheritance occurs when a class inherits the attributes and methods of another class. In the following example, the Child class inherits the same attributes as the Parent class while creating its own unrelated attributes. Child Parent class Child(Parent):
    def __init__( self, name, hair_color, age, major):
        super().__init__(name, hair_color, age)
        self.major = major

    def description(self):
        super().description()
        print(f"Name: {self.name}")
        print(f"Hair Color: {self.get_hair_color()")
        print(f"Age: {self.get_age()}")
        print(f"Major: {self.major}")

child = Child("Dwight", "Auburn", 20, "Computer Science")
child.description()
#Output
# I'm Dwight, my hair color is Auburn!
# Name: Dwight
# Hair Color: Auburn
# Age: 20
# Major: "Computer Science class Child(Parent):
    def __init__( self, name, hair_color, age, major):
        super().__init__(name, hair_color, age)
        self.major = major

    def description(self):
        super().description()
        print(f"Name: {self.name}")
        print(f"Hair Color: {self.get_hair_color()")
        print(f"Age: {self.get_age()}")
        print(f"Major: {self.major}")

child = Child("Dwight", "Auburn", 20, "Computer Science")
child.description()
#Output
# I'm Dwight, my hair color is Auburn!
# Name: Dwight
# Hair Color: Auburn
# Age: 20
# Major: "Computer Science Polymorphism Polymorphism  allows you to override or modify class methods in subclasses. As seen in the previous snippet on Inheritance, the Child class adapts and modifies the Parent method description() . By including the super().description() within the description() method, you can adapt the inclusion of the Parent output into the Child ’s description() method output. In the next snippet, the Child class inherits the attributes of the Parent class but overrides the description() method, resulting in a different output. Child Parent description() super().description() description() Parent Child description() Child Parent description() class Child(Parent):
    def __init__(self, name, hair_color, age, major):
        super().__init__(name, hair_color, age)
        self.major = major

    def description(self):
        print(f"Hello my name is {self.name}, I'm {self.get_age()} and I major in {self.major}!")

parent = Parent("Charles", "Grey", 45)
child = Child("Dwight", "Auburn", 20, "Computer Science")
parent.description()
#Output
# I'm Charles, my hair color is Grey!

child.description()
# Hello my name is Dwight, I'm 20 and I major in Computer Science! class Child(Parent):
    def __init__(self, name, hair_color, age, major):
        super().__init__(name, hair_color, age)
        self.major = major

    def description(self):
        print(f"Hello my name is {self.name}, I'm {self.get_age()} and I major in {self.major}!")

parent = Parent("Charles", "Grey", 45)
child = Child("Dwight", "Auburn", 20, "Computer Science")
parent.description()
#Output
# I'm Charles, my hair color is Grey!

child.description()
# Hello my name is Dwight, I'm 20 and I major in Computer Science! Association Association in programming is versatile, as it can be one-to-one, one-to-many, or many-to-many. It refers to the relationship between two classes where one class uses another. In the following example, we will use a one-to-many relation between classes. The Parent class can have many children, and we can add multiple Child instances via the add_child() method. Parent Child add_child() class Parent:
    def __init__(self, name):
        self.name = name
        self.children = []

    def add_child(self, child):
        self.children.append(child)

    def list_children(self):
        return [child.name for child in self.children]

    def number_of_children(self):
        if not self.children:
            return "No children"
        return len(self.children)

class Child:
    def __init__(self, name, age):
        self.name = name
        self.age = age

parent = Parent("James")
child1 = Child("James Jr.", 12)
child2 = Child("Cameron", 16)

parent.add_child(child1)
parent.add_child(child2)

# List Children
for child in parent.list_children():
    print(child)

# James Jr.
# Cameron

parent.number_of_children()

# 2 class Parent:
    def __init__(self, name):
        self.name = name
        self.children = []

    def add_child(self, child):
        self.children.append(child)

    def list_children(self):
        return [child.name for child in self.children]

    def number_of_children(self):
        if not self.children:
            return "No children"
        return len(self.children)

class Child:
    def __init__(self, name, age):
        self.name = name
        self.age = age

parent = Parent("James")
child1 = Child("James Jr.", 12)
child2 = Child("Cameron", 16)

parent.add_child(child1)
parent.add_child(child2)

# List Children
for child in parent.list_children():
    print(child)

# James Jr.
# Cameron

parent.number_of_children()

# 2 Conclusion Object-oriented programming (OOP) offers a robust framework for developing modular, reusable, and maintainable code. Its foundational concepts, such as classes, objects, encapsulation, inheritance, polymorphism, and association, enable developers to create scalable and efficient software solutions. This efficiency makes OOP an indispensable paradigm in modern programming. Embracing OOP enhances code organization and facilitates easier debugging and future-proofing of applications, making developers more productive and effective.

Object-oriented Programming by Example

Full Guide to Hiring a Salesforce Pardot Consultant

সেলসফোর্স পারডট কনসালটেন্ট নিয়োগের সম্পূর্ণ নির্দেশিকা

Vollständiger Leitfaden zur Einstellung eines Salesforce Pardot-Beraters

Guía completa para contratar un consultor de Salesforce Pardot

Guide complet pour embaucher un consultant Salesforce Pardot

Salesforce Pardot सलाहकार को नियुक्त करने के लिए पूर्ण गाइड

Salesforce Pardot コンサルタントを雇うための完全ガイド

Salesforce Pardot 컨설턴트 채용에 대한 전체 가이드

Guia completo para contratar um consultor Salesforce Pardot

Полное руководство по найму консультанта Salesforce Pardot

Salesforce Pardot Danışmanı Kiralamaya İlişkin Tam Kılavuz

Hướng dẫn đầy đủ về việc thuê tư vấn viên Pardot của Salesforce

聘请 Salesforce Pardot 顾问的完整指南

Paramount/Skydance: The Birth of a New Hollywood Mogul?

Authors:
(1) Moritz Jasper, Barkhausen Institut gGmbH, Wurzburger Straße 46, Dresden, Germany (moritz.jasperl@barkhauseninstitut.org);
(2) Stefan Kopsell, Barkhausen Institut gGmbH, Wurzburger Straße 46, Dresden, Germany (stefan.koepsell@barkhauseninstitut.org). Table of Links Abstract and Introduction Related Work Description of LCM Attacker Model and Security Goals LCMSec: The Proposed Protocol Implementation and Evaluation Conclusion Appendix and References APPENDIX A. Two attacks on the Dutta-Barua group key agreement Zhang et al. present two attacks on the DBGKA protocol [23]. To fully understand them and this section, some understanding of the Dutta-Barua protocol [17] is required. While a full review of the protocol is out of scope for this work, for the purposes of this section, the most important thing is to understand that each KeyAgree() and Join() operation is associated with an instance id d. This instance id is incremented for each of those operations and can never be reused. Note that d can be regarded as a nonce: while it is not random, it is never reused. Another example of a protocol that uses non-random nonces is Wireguard [24]. Both attacks described by Zhang et al. are carried out by one or multiple malicious users who are part of the Dutta-Barua group, that is they have successfully participated in the DuttaBarua key agreement in the past. In this sense, the premise of the DBGKA is already violated: The DBGKA protocol provides no security against malicious insiders. Nevertheless, one should take this form of attack seriously: An honest user - representing, for instance, an IoT device - might at some point be compromised and become dishonest. Alternatively, he might have been dishonest all along, but his certificate is only revoked at a later stage. We will therefore discuss both attacks and show why they pose no threat to the LCMsec protocol. 1) First Attack: The first attack is carried out by a malicious leaving user who has been part of a previous successful DuttaBarua KeyAgreement() operation during which he has made some preparation for the attack by storing some of the protocol messages. When the Leave() operation is executed to expel this user from the group, Zhang et. al. show that the attacker can compute the new session key using the values he stored earlier. However, as we understand the DBGKA, the purpose of the Leave() operation is not to expel dishonest users, but as a way for honest users to leave. When an honest user leaves in this way, it is possible for the remaining users to efficiently agree on a new key. If an honest user, on the other hand, does not execute the Leave() operation, a new KeyAgreement() operation has to performed, which is a lot less efficient for large groups. To expel a malicious user, the remaining users instead execute the KeyAgree() operation amongst themselves – this way, the attack is bypassed entirely. Note that in the current version of LCMsec, we do not include a mechanism for certificate revocation or expelling users from the group and make no use of the Leave() operation, so this attack does not concern us. Still, the ability to add such a feature in the future is important. As we discussed, this can be done safely by using the KeyAgree() operation whenever a certificate is revoked. REFERENCES [1] P. T. Eugster, P. A. Felber, R. Guerraoui, and A.-M. Kermarrec, “The many faces of publish/subscribe,” ACM Computing Surveys, vol. 35, no. 2, pp. 114–131, Jun. 2003. [2] A. S. Huang, E. Olson, and D. C. Moore, “LCM: Lightweight Communications and Marshalling,” in 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems, pp. 4057–4062. [3] R. Canetti, J. Garay, G. Itkis, D. Micciancio, M. Naor, and B. Pinkas, “Multicast security: A taxonomy and some efficient constructions,” in IEEE INFOCOM ’99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Societies. The Future Is Now (Cat. No.99CH36320), pp. 708–716 vol.2. [4] “Message Queuing Telemetry Transport.” [Online]. Available: https: //mqtt.org/ [5] G. Pardo-Castellote, “OMG Data-Distribution Service: Architectural overview,” in 23rd International Conference on Distributed Computing Systems Workshops, 2003. Proceedings., May 2003, pp. 200–206. [6] S. E. Deering, “Host extensions for IP multicasting,” Internet Engineering Task Force, Request for Comments RFC 1112, Aug. 1989. [7] E. Onica, P. Felber, H. Mercier, and E. Riviere, “Towards Scalable ` and Dependable Privacy-Preserving Publish/Subscribe Services,” in Fast Abstract in the 46th Annual IEEE/IFIP International Conference on Dependable Systems and Networks, M. Roy, J. A. Lopez, and A. Casimiro, Eds., Toulouse, France, Jun. 2016. [8] S. Bernard, M. G. Potop-Butucaru, and S. Tixeuil, “A Framework for Secure and Private P2P Publish/Subscribe,” in Stabilization, Safety, and Security of Distributed Systems, ser. Lecture Notes in Computer Science, S. Dolev, J. Cobb, M. Fischer, and M. Yung, Eds., pp. 531–545. [9] L. Malina, G. Srivastava, P. Dzurenda, J. Hajny, and R. Fujdiak, “A Secure Publish/Subscribe Protocol for Internet of Things,” in Proceedings of the 14th International Conference on Availability, Reliability and Security, ser. ARES ’19, pp. 1–10. [10] M. Ion, G. Russello, and B. Crispo, “Supporting Publication and Subscription Confidentiality in Pub/Sub Networks,” in Security and Privacy in Communication Networks, ser. Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, S. Jajodia and J. Zhou, Eds., pp. 272–289. [11] M. Hamad, E. Regnath, J. Lauinger, V. Prevelakis, and S. Steinhorst, “SPPS: Secure Policy-based Publish/Subscribe System for V2C Communication,” in 2021 Design, Automation & Test in Europe Conference & Exhibition (DATE), Feb. 2021, pp. 529–534. [12] M. Dahlmanns, J. Pennekamp, I. B. Fink, B. Schoolmann, K. Wehrle, and M. Henze, “Transparent End-to-End Security for Publish/Subscribe Communication in Cyber-Physical Systems,” in Proceedings of the 2021 ACM Workshop on Secure and Trustworthy Cyber-Physical Systems, ser. SAT-CPS ’21, pp. 78–87. [13] iMatix Corporation, “ZeroMQ Broker vs . Brokerless Messaging - Whitepaper.” [Online]. Available: http://wiki.zeromq.org/whitepapers: brokerless [14] iMatix Corporation, “CurveZMQ - a protocol for secure messaging across the Internet,” Jan. 2023. [Online]. Available: http://rfc.zeromq. org/spec/26/ [15] Object Management Group, “DDS Security Specification,” Jun. 2018. [Online]. Available: https://www.omg.org/spec/DDS-SECURITY/1.1/ PDF [16] J. Kim, J. M. Smereka, C. Cheung, S. Nepal, and M. Grobler, “Security and Performance Considerations in ROS 2: A Balancing Act,” Sep. 2018. [Online]. Available: http://arxiv.org/abs/1809.09566 [17] R. Dutta and R. Barua, “Provably Secure Constant Round Contributory Group Key Agreement in Dynamic Setting,” IEEE Transactions on Information Theory, vol. 54, no. 5, pp. 2007–2025, May 2008. [18] D. Ongaro and J. Ousterhout, “In search of an understandable consensus algorithm,” in Proceedings of the 2014 USENIX Conference on USENIX Annual Technical Conference, ser. USENIX ATC’14, pp. 305–320. [19] M. J. Dworkin, “Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC,” NIST, Nov. 2007. [20] R. Atkinson and S. Kent, “Security Architecture for the Internet Protocol,” Internet Engineering Task Force, Request for Comments RFC 2401, Nov. 1998. [21] T. T. T. ZOU) and X. Zhang, “IPsec Anti-Replay Algorithm without Bit Shifting,” Internet Engineering Task Force, Request for Comments RFC 6479, Jan. 2012. [22] S. Boeyen, S. Santesson, T. Polk, R. Housley, S. Farrell, and D. Cooper, “Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile,” Internet Engineering Task Force, Request for Comments RFC 5280, May 2008. [23] H. Zhang, C. Xu, C. Li, and A. R. Sangi, “Two Attacks on Dutta’s Dynamic Group Key Agreement Protocol,” in Wireless Communications and Applications, ser. Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, P. Senac, M. Ott, and A. Seneviratne, Eds., pp. 419–425. ´ [24] J. A. Donenfeld, “WireGuard: Next Generation Kernel Network Tunnel,” in Proceedings 2017 Network and Distributed System Security Symposium. This paper is available on arxiv under CC BY 4.0 DEED license. Authors: (1) Moritz Jasper, Barkhausen Institut gGmbH, Wurzburger Straße 46, Dresden, Germany (moritz.jasperl@barkhauseninstitut.org); (2) Stefan Kopsell, Barkhausen Institut gGmbH, Wurzburger Straße 46, Dresden, Germany (stefan.koepsell@barkhauseninstitut.org). Authors: Authors: (1) Moritz Jasper, Barkhausen Institut gGmbH, Wurzburger Straße 46, Dresden, Germany (moritz.jasperl@barkhauseninstitut.org); (2) Stefan Kopsell, Barkhausen Institut gGmbH, Wurzburger Straße 46, Dresden, Germany (stefan.koepsell@barkhauseninstitut.org). Table of Links Abstract and Introduction Abstract and Introduction Related Work Related Work Description of LCM Description of LCM Attacker Model and Security Goals Attacker Model and Security Goals LCMSec: The Proposed Protocol LCMSec: The Proposed Protocol Implementation and Evaluation Implementation and Evaluation Conclusion Conclusion Appendix and References Appendix and References APPENDIX A. Two attacks on the Dutta-Barua group key agreement A. Two attacks on the Dutta-Barua group key agreement Zhang et al. present two attacks on the DBGKA protocol [23]. To fully understand them and this section, some understanding of the Dutta-Barua protocol [17] is required. While a full review of the protocol is out of scope for this work, for the purposes of this section, the most important thing is to understand that each KeyAgree() and Join() operation is associated with an instance id d. This instance id is incremented for each of those operations and can never be reused. Note that d can be regarded as a nonce: while it is not random, it is never reused. Another example of a protocol that uses non-random nonces is Wireguard [24]. Both attacks described by Zhang et al. are carried out by one or multiple malicious users who are part of the Dutta-Barua group, that is they have successfully participated in the DuttaBarua key agreement in the past. In this sense, the premise of the DBGKA is already violated: The DBGKA protocol provides no security against malicious insiders. Nevertheless, one should take this form of attack seriously: An honest user - representing, for instance, an IoT device - might at some point be compromised and become dishonest. Alternatively, he might have been dishonest all along, but his certificate is only revoked at a later stage. We will therefore discuss both attacks and show why they pose no threat to the LCMsec protocol. 1) First Attack : The first attack is carried out by a malicious leaving user who has been part of a previous successful DuttaBarua KeyAgreement() operation during which he has made some preparation for the attack by storing some of the protocol messages. When the Leave() operation is executed to expel this user from the group, Zhang et. al. show that the attacker can compute the new session key using the values he stored earlier. 1) First Attack DuttaBarua KeyAgreement() Leave() However, as we understand the DBGKA, the purpose of the Leave() operation is not to expel dishonest users, but as a way for honest users to leave. When an honest user leaves in this way, it is possible for the remaining users to efficiently agree on a new key. If an honest user, on the other hand, does not execute the Leave() operation, a new KeyAgreement() operation has to performed, which is a lot less efficient for large groups. To expel a malicious user, the remaining users instead execute the KeyAgree() operation amongst themselves – this way, the attack is bypassed entirely. Leave() Leave() KeyAgreement() KeyAgree() Note that in the current version of LCMsec, we do not include a mechanism for certificate revocation or expelling users from the group and make no use of the Leave() operation, so this attack does not concern us. Still, the ability to add such a feature in the future is important. As we discussed, this can be done safely by using the KeyAgree() operation whenever a certificate is revoked. Leave() KeyAgree() REFERENCES [1] P. T. Eugster, P. A. Felber, R. Guerraoui, and A.-M. Kermarrec, “The many faces of publish/subscribe,” ACM Computing Surveys, vol. 35, no. 2, pp. 114–131, Jun. 2003. [2] A. S. Huang, E. Olson, and D. C. Moore, “LCM: Lightweight Communications and Marshalling,” in 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems, pp. 4057–4062. [3] R. Canetti, J. Garay, G. Itkis, D. Micciancio, M. Naor, and B. Pinkas, “Multicast security: A taxonomy and some efficient constructions,” in IEEE INFOCOM ’99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Societies. The Future Is Now (Cat. No.99CH36320), pp. 708–716 vol.2. [4] “Message Queuing Telemetry Transport.” [Online]. Available: https: //mqtt.org/ [5] G. Pardo-Castellote, “OMG Data-Distribution Service: Architectural overview,” in 23rd International Conference on Distributed Computing Systems Workshops, 2003. Proceedings., May 2003, pp. 200–206. [6] S. E. Deering, “Host extensions for IP multicasting,” Internet Engineering Task Force, Request for Comments RFC 1112, Aug. 1989. [7] E. Onica, P. Felber, H. Mercier, and E. Riviere, “Towards Scalable ` and Dependable Privacy-Preserving Publish/Subscribe Services,” in Fast Abstract in the 46th Annual IEEE/IFIP International Conference on Dependable Systems and Networks, M. Roy, J. A. Lopez, and A. Casimiro, Eds., Toulouse, France, Jun. 2016. [8] S. Bernard, M. G. Potop-Butucaru, and S. Tixeuil, “A Framework for Secure and Private P2P Publish/Subscribe,” in Stabilization, Safety, and Security of Distributed Systems, ser. Lecture Notes in Computer Science, S. Dolev, J. Cobb, M. Fischer, and M. Yung, Eds., pp. 531–545. [9] L. Malina, G. Srivastava, P. Dzurenda, J. Hajny, and R. Fujdiak, “A Secure Publish/Subscribe Protocol for Internet of Things,” in Proceedings of the 14th International Conference on Availability, Reliability and Security, ser. ARES ’19, pp. 1–10. [10] M. Ion, G. Russello, and B. Crispo, “Supporting Publication and Subscription Confidentiality in Pub/Sub Networks,” in Security and Privacy in Communication Networks, ser. Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, S. Jajodia and J. Zhou, Eds., pp. 272–289. [11] M. Hamad, E. Regnath, J. Lauinger, V. Prevelakis, and S. Steinhorst, “SPPS: Secure Policy-based Publish/Subscribe System for V2C Communication,” in 2021 Design, Automation & Test in Europe Conference & Exhibition (DATE), Feb. 2021, pp. 529–534. [12] M. Dahlmanns, J. Pennekamp, I. B. Fink, B. Schoolmann, K. Wehrle, and M. Henze, “Transparent End-to-End Security for Publish/Subscribe Communication in Cyber-Physical Systems,” in Proceedings of the 2021 ACM Workshop on Secure and Trustworthy Cyber-Physical Systems, ser. SAT-CPS ’21, pp. 78–87. [13] iMatix Corporation, “ZeroMQ Broker vs . Brokerless Messaging - Whitepaper.” [Online]. Available: http://wiki.zeromq.org/whitepapers: brokerless [14] iMatix Corporation, “CurveZMQ - a protocol for secure messaging across the Internet,” Jan. 2023. [Online]. Available: http://rfc.zeromq. org/spec/26/ [15] Object Management Group, “DDS Security Specification,” Jun. 2018. [Online]. Available: https://www.omg.org/spec/DDS-SECURITY/1.1/ PDF [16] J. Kim, J. M. Smereka, C. Cheung, S. Nepal, and M. Grobler, “Security and Performance Considerations in ROS 2: A Balancing Act,” Sep. 2018. [Online]. Available: http://arxiv.org/abs/1809.09566 [17] R. Dutta and R. Barua, “Provably Secure Constant Round Contributory Group Key Agreement in Dynamic Setting,” IEEE Transactions on Information Theory, vol. 54, no. 5, pp. 2007–2025, May 2008. [18] D. Ongaro and J. Ousterhout, “In search of an understandable consensus algorithm,” in Proceedings of the 2014 USENIX Conference on USENIX Annual Technical Conference, ser. USENIX ATC’14, pp. 305–320. [19] M. J. Dworkin, “Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC,” NIST, Nov. 2007. [20] R. Atkinson and S. Kent, “Security Architecture for the Internet Protocol,” Internet Engineering Task Force, Request for Comments RFC 2401, Nov. 1998. [21] T. T. T. ZOU) and X. Zhang, “IPsec Anti-Replay Algorithm without Bit Shifting,” Internet Engineering Task Force, Request for Comments RFC 6479, Jan. 2012. [22] S. Boeyen, S. Santesson, T. Polk, R. Housley, S. Farrell, and D. Cooper, “Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile,” Internet Engineering Task Force, Request for Comments RFC 5280, May 2008. [23] H. Zhang, C. Xu, C. Li, and A. R. Sangi, “Two Attacks on Dutta’s Dynamic Group Key Agreement Protocol,” in Wireless Communications and Applications, ser. Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, P. Senac, M. Ott, and A. Seneviratne, Eds., pp. 419–425. ´ [24] J. A. Donenfeld, “WireGuard: Next Generation Kernel Network Tunnel,” in Proceedings 2017 Network and Distributed System Security Symposium. This paper is available on arxiv under CC BY 4.0 DEED license. This paper is available on arxiv under CC BY 4.0 DEED license. available on arxiv

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