Group items tagged

Geographical access control may be enforced by personnel (e.g., border guard, bouncer, ticket checker)

n alternative of access control in the strict sense (physically controlling access itself) is a system of checking authorized presence, see e.g. Ticket controller (transportation). A variant is exit control, e.g. of a shop (checkout) or a country

access control refers to the practice of restricting entrance to a property, a building, or a room to authorized persons

can be achieved by a human (a guard, bouncer, or receptionist), through mechanical means such as locks and keys, or through technological means such as access control systems like the mantrap.

Physical access control is a matter of who, where, and when

Historically, this was partially accomplished through keys and locks. When a door is locked, only someone with a key can enter through the door, depending on how the lock is configured. Mechanical locks and keys do not allow restriction of the key holder to specific times or dates. Mechanical locks and keys do not provide records of the key used on any specific door, and the keys can be easily copied or transferred to an unauthorized person. When a mechanical key is lost or the key holder is no longer authorized to use the protected area, the locks must be re-keyed.[citation needed] Electronic access control uses computers to solve the limitations of mechanical locks and keys. A wide range of credentials can be used to replace mechanical keys. The electronic access control system grants access based on the credential presented. When access is granted, the door is unlocked for a predetermined time and the transaction is recorded. When access is refused, the door remains locked and the attempted access is recorded. The system will also monitor the door and alarm if the door is forced open or held open too long after being unlocked

Credential

Access control system operation

The above description illustrates a single factor transaction. Credentials can be passed around, thus subverting the access control list. For example, Alice has access rights to the server room, but Bob does not. Alice either gives Bob her credential, or Bob takes it; he now has access to the server room. To prevent this, two-factor authentication can be used. In a two factor transaction, the presented credential and a second factor are needed for access to be granted; another factor can be a PIN, a second credential, operator intervention, or a biometric input

There are three types (factors) of authenticating information:[2] something the user knows, e.g. a password, pass-phrase or PIN something the user has, such as smart card or a key fob something the user is, such as fingerprint, verified by biometric measurement

Passwords are a common means of verifying a user's identity before access is given to information systems. In addition, a fourth factor of authentication is now recognized: someone you know, whereby another person who knows you can provide a human element of authentication in situations where systems have been set up to allow for such scenarios

When a credential is presented to a reader, the reader sends the credential’s information, usually a number, to a control panel, a highly reliable processor. The control panel compares the credential's number to an access control list, grants or denies the presented request, and sends a transaction log to a database. When access is denied based on the access control list, the door remains locked.

A credential is a physical/tangible object, a piece of knowledge, or a facet of a person's physical being, that enables an individual access to a given physical facility or computer-based information system. Typically, credentials can be something a person knows (such as a number or PIN), something they have (such as an access badge), something they are (such as a biometric feature) or some combination of these items. This is known as multi-factor authentication. The typical credential is an access card or key-fob, and newer software can also turn users' smartphones into access devices.

An access control point, which can be a door, turnstile, parking gate, elevator, or other physical barrier, where granting access can be electronically controlled. Typically, the access point is a door. An electronic access control door can contain several elements. At its most basic, there is a stand-alone electric lock. The lock is unlocked by an operator with a switch. To automate this, operator intervention is replaced by a reader. The reader could be a keypad where a code is entered, it could be a card reader, or it could be a biometric reader. Readers do not usually make an access decision, but send a card number to an access control panel that verifies the number against an access list

monitor the door position

Generally only entry is controlled, and exit is uncontrolled. In cases where exit is also controlled, a second reader is used on the opposite side of the door. In cases where exit is not controlled, free exit, a device called a request-to-exit (REX) is used. Request-to-exit devices can be a push-button or a motion detector. When the button is pushed, or the motion detector detects motion at the door, the door alarm is temporarily ignored while the door is opened. Exiting a door without having to electrically unlock the door is called mechanical free egress. This is an important safety feature. In cases where the lock must be electrically unlocked on exit, the request-to-exit device also unlocks the doo

Access control topology

Access control decisions are made by comparing the credential to an access control list. This look-up can be done by a host or server, by an access control panel, or by a reader. The development of access control systems has seen a steady push of the look-up out from a central host to the edge of the system, or the reader. The predominant topology circa 2009 is hub and spoke with a control panel as the hub, and the readers as the spokes. The look-up and control functions are by the control panel. The spokes communicate through a serial connection; usually RS-485. Some manufactures are pushing the decision making to the edge by placing a controller at the door. The controllers are IP enabled, and connect to a host and database using standard networks

Access control readers may be classified by the functions they are able to perform

and forward it to a control panel.

Basic (non-intelligent) readers: simply read

Semi-intelligent readers: have all inputs and outputs necessary to control door hardware (lock, door contact, exit button), but do not make any access decisions. When a user presents a card or enters a PIN, the reader sends information to the main controller, and waits for its response. If the connection to the main controller is interrupted, such readers stop working, or function in a degraded mode. Usually semi-intelligent readers are connected to a control panel via an RS-485 bus.

Intelligent readers: have all inputs and outputs necessary to control door hardware; they also have memory and processing power necessary to make access decisions independently. Like semi-intelligent readers, they are connected to a control panel via an RS-485 bus. The control panel sends configuration updates, and retrieves events from the readers.

Systems with IP readers usually do not have traditional control panels, and readers communicate directly to a PC that acts as a host

a built in webservice to make it user friendly

Some readers may have additional features such as an LCD and function buttons for data collection purposes (i.e. clock-in/clock-out events for attendance reports), camera/speaker/microphone for intercom, and smart card read/write support

we are interested in the resilience that comes from building a rich ecosystem of interoperable currencies

What are the core elements of a modern cryptocurrency?

Digital

Holdings are electronic and only exist and operate by virtue of a community’s agreement about how to interpret digital bits according to rules about operation and accounting of the currency.

Trustless

don’t have to trust a 3rd party central authority

Decentralized

Specifically, access, issuance, transaction accounting, rules & policies, should be collectively visible, known, and held.

Cryptographic

This cryptographic structure is used to enable a variety of people to host the data without being able to alter it.

Identity

there must be a way to associate these bits with some kind of account, wallet, owner, or agent who can use them

Other things that many take for granted in blockchains may not be core but subject to decisions in design and implementation, so they can vary between implementations

It does not have to be stored in a synchronized global ledger

does not have to be money. It may be a reputation currency, or data used for identity, or naming, etc

Its units do not have to be cryptographic tokens or coins

It does not have to protect the anonymity of users, although it may

if you think currency is only money, and that money must be artificially scarce

Then you must tackle the problem of always tracking which coins exist, and which have been spent. That is one approach — the one blockchain takes.

You might optimize for anonymity if you think of cryptocurrency as a tool to escape governments, regulations, and taxes.

if you want to establish and manage membership in new kinds of commons, then identity and accountability for actions may turn out to be necessary ingredients instead of anonymity.

In the case of the MetaCurrency Project, we are trying to support many use cases by building tools to enable a rich ecosystem of communities and current-sees (many are non-monetary) to enhance collective intelligence at all scales.

Managing consensus about a shared reality is a central challenge at the heart of all distributed computing solutions.

If we want to democratize money by having cryptocurrencies become a significant and viable means of transacting on a daily basis, I believe we need fundamentally more scalable approaches that don’t require expensive, dedicated hardware just to participate.

We should not need system wide consensus for two people to do a transaction in a cryptocurrency

Blockchain is about managing a consensus about what was “said.” Ceptr is about distributing a consensus about how to “speak.”

how nature gets the job done in massively scalable systems which require coordination and consistency

Replicate the same processes across all nodes

Empower every node with full agency

Hold this transformed state locally and reliably

Establish protocols for interaction

Each speaker of a language carries the processes to understand sentences they hear, and generate sentences they need

we certainly don’t carry some kind of global ledger of everything that’s ever been said, or require consensus about what has been said

Language IS a communication protocol we learn by emulating the processes of usage.

Dictionaries try to catch up when the usage

there is certainly no global ledger with consensus about the state of trillions of cells. Yet, from a single zygote’s copy of DNA, our cells coordinate in a highly decentralized manner, on scales of trillions, and without the latency or bottlenecks of central control.

Imagine something along the lines of a Java Virtual Machine connected to a distributed version of Github

Every time this JVM runs a program it confirms the hash of the code it is about to execute with the hash signed into the code repository by its developers

This allows each node that intends to be honest to be sure that they’re running the same processes as everyone else. So when two parties want to do a transaction, and each can have confidence their own code, and the results that your code produces

Then you treat it as authoritative and commit it to your local cryptographically self-validating data store

Allowing each node to treat itself as a full authority to process transactions (or interactions via shared protocols) is exactly how you empower each node with full agency. Each node runs its copy of the signed program/processes on its own virtual machine, taking the transaction request combined with the transaction chains of the parties to the transaction. Each node can confirm their counterparty’s integrity by replaying their transactions to produce their current state, while confirming signatures and integrity of the chain

If both nodes are in an appropriate state which allows the current transaction, then they countersign the transaction and append to their respective chains. When you encounter a corrupted or dishonest node (as evidenced by a breach of integrity of their chain — passing through an invalid state, broken signatures, or broken links), your node can reject the transaction you were starting to process. Countersigning allows consensus at the appropriate scale of the decision (two people transacting in this case) to lock data into a tamper-proof state so it can be stored in as many parallel chains as you need.

When your node appends a mutually validated and signed transaction to its chain, it has updated its local state and is able to represent the integrity of its data locally. As long as each transaction (link in the chain) has valid linkages and countersignatures, we can know that it hasn’t been tampered with.

If you can reliably embody the state of the node in the node itself using Intrinsic Data Integrity, then all nodes can interact in parallel, independent of other interactions to maximize scalability and simultaneous processing. Either the node has the credits or it doesn’t. I don’t have to refer to a global ledger to find out, the state of the node is in the countersigned, tamper-proof chain.

Just like any meaningful communication, a protocol needs to be established to make sure that a transaction carries all the information needed for each node to run the processes and produce a new signed and chained state. This could be debits or credits to an account which modify the balance, or recoding courses and grades to a transcript which modify a Grade Point Average, or ratings and feedback contributing to a reputation score, and so on.

By distributing process at the foundation, and leveraging Intrinsic Data Integrity, our approach results in massive improvements in throughput (from parallel simultaneous independent processing), speed, latency, efficiency, and cost of hardware.

You also don’t need to incent people to hold their own record — they already want it.

Another noteworthy observation about humans, cells, and atoms, is that each has a general “container” that gets configured to a specific use.

Likewise, the Receptors we’ve built are a general purpose framework which can load code for different distributed applications. These Receptors are a lightweight processing container for the Ceptr Virtual Machine Host

Ceptr enables a developer to focus on the rules and transactions for their use case instead of building a whole framework for distributed applications.

how units in a currency are issued

Most people think that money is just money, but there are literally hundreds of decisions you can make in designing a currency to target particular needs, niches, communities or patterns of flow.

Blockchain cryptocurrencies are fiat currencies. They create tokens or coins from nothing

These coins are just “spoken into being”

the challenging task of

ensure there is no counterfeiting or double-spending

Blockchain cryptocurrencies are fiat currencies

These coins are just “spoken into being”

the challenging task of tracking all the coins that exist to ensure there is no counterfeiting or double-spending

You wouldn’t need to manage consensus about whether a cryptocoin is spent, if your system created accounts which have normal balances based on summing their transactions.

In a mutual credit system, units of currency are issued when a participant extends credit to another user in a standard spending transaction

Alice pays Bob 20 credits for a haircut. Alice’s account now has -20, and Bob’s has +20.

Alice spent credits she didn’t have! True

Managing the currency supply in a mutual credit system is about managing credit limits — how far people can spend into a negative balance

Notice the net number units in the system remains zero

One elegant approach to managing mutual credit limits is to set them based on actual demand.

concerns about manufacturing fake accounts to game credit limits (Sybil Attacks)

keep in mind there can be different classes of accounts. Easy to create, anonymous accounts may get NO credit limit

What if I alter my code to give myself an unlimited credit limit, then spend as much as I want? As soon as you pass the credit limit encoded in the shared agreements, the next person you transact with will discover you’re in an invalid state and refuse the transaction.

If two people collude to commit an illegal transaction by both hacking their code to allow a normally invalid state, the same still pattern still holds. The next person they try to transact with using untampered code will detect the problem and decline to transact.

Most modern community currency systems have been implemented as mutual credit,

Hawala is a network of merchants and businessmen, which has been operating since the middle ages, performing money transfers on an honor system and typically settling balances through merchandise instead of transferring money

Let’s look at building a minimum viable cryptocurrency with the hawala network as our use case

To minimize key management infrastructure, each hawaladar’s public key is their address or identity on the network. To join the network you get a copy of the software from another hawaladar, generate your public and private keys, and complete your personal profile (name, location, contact info, etc.). You call, fax, or email at least 10 hawaladars who know you, and give them your IP address and ask them to vouch for you.

Once 10 other hawaladars have vouched for you, you can start doing other transactions because the protocol encoded in every node will reject a transaction chain that doesn’t start with at least 10 vouches

seeding your information with those other peers so you can be found by the rest of the network.

As described in the Mutual Credit section, at the time of transaction each party audits the counterparty’s transaction chain.

Our hawala crypto-clearinghouse protocol has two categories of transactions: some used for accounting and others for routing. Accounting transactions change balances. Routing transactions maintain network integrity by recording information about hawaladar

Accounting Transactions create signed data that changes account balances and contains these fields:

The final hash of all of the above fields is used as a unique transaction ID and is what each of party signs with their private keys. Signing indicates a party has agreed to the terms of the transaction. Only transactions signed by both parties are considered valid. Nodes can verify signatures by confirming that decryption of the signature using the public key yields a result which matches the transaction ID.

Routing Transactions sign data that changes the peers list and contain these fields:

As with accounting transactions, the hash of the above fields is used as the transaction’s unique key and the basis for the cryptographic signature of both counterparties.

Remember, instead of making changes to account balances, routing transactions change a node’s local list of peers for finding each other and processing.

a distributed network of mutual trust

operates across national boundaries

everyone already keeps and trusts their own separate records

Hawaladars are not anonymous

“double-spending”

It would be possible for someone to hack the code on their node to “forget” their most recent transaction (drop the head of their chain), and go back to their previous version of the chain before that transaction. Then they could append a new transaction, drop it, and append again.

After both parties have signed the agreed upon transaction, each party submits the transaction to separate notaries. Notaries are a special class of participant who validate transactions (auditing each chain, ensuring nobody passes through an invalid state), and then they sign an outer envelope which includes the signatures of the two parties. Notaries agree to run high-availability servers which collectively manage a Distributed Hash Table (DHT) servicing requests for transaction information. As their incentive for providing this infrastructure, notaries get a small transaction fee.

This approach introduces a few more steps and delays to the transaction process, but because it operates on independent parallel chains, it is still orders of magnitude more efficient and decentralized than reaching consensus on entries in a global ledger

millions of simultaneous transactions could be getting processed by other parties and notaries with no bottlenecks.

There are other solutions to prevent nodes from dropping the head of their transaction chain, but the approach of having notaries serve out a DHT solves a number of common objections to completely distributed accounting. Having access to reliable lookups in a DHT provides a similar big picture view that you get from a global ledger. For example, you may want a way to look up transactions even when the parties to that transaction are offline, or to be able to see the net system balance at a particular moment in time, or identify patterns of activity in the larger system without having to collect data from everyone individually.

By leveraging Intrinsic Data Integrity to run numerous parallel tamper-proof chains you can enable nodes to do various P2P transactions which don’t actually require group consensus. Mutual credit is a great way to implement cryptocurrencies to run in this peered manner. Basic PKI with a DHT is enough additional infrastructure to address main vulnerabilities. You can optimize your solution architecture by reserving reserve consensus work for tasks which need to guarantee uniqueness or actually involve large scale agreement by humans or automated contracts.

It is not only possible, but far more scalable to build cryptocurrencies without a global ledger consensus approach or cryptographic tokens.

Donald Davidson

an action

is something an agent does that was ‘intentional under some description,’

there have been many attempts to map the relations between intentions for the future, acting intentionally, and acting with a certain intention.

There has been a notable or notorious debate about whether the agent's reasons in acting are causes of the action

rendered the action intelligible in his eyes

things that merely happen

things they genuinely do

distinction between

the doings, are the acts or actions of the agent

what distinguishes an action from a mere happening or occurrence?

An agent performs activity that is directed at a goal

adopted on the basis of an overall practical assessment of his options and opportunities

awareness

that he is performing the activity

and that the activity is aimed by him at such-and-such a chosen end

It is frequently noted that the agent has some sort of immediate awareness of his physical activity and of the goals that the activity is aimed at realizing.

‘knowledge without observation.’

It is also important to the concept of ‘goal directed action’ that agents normally implement a kind of direct control or guidance over their own behavior.

For many years, the most intensely debated topic in the philosophy of action concerned the explanation of intentional actions in terms of the agent's reasons for acting

Davidson and other action theorists defended the position that reason explanations are causal explanations

In the foregoing, reference has been made to explanations of actions in terms of reasons, but recent work on agency has questioned whether contemporary frameworks for the philosophy of action have really articulated the way in which an agent's desires and other pro-attitudes have the distinctive force of reasons in the setting of these ordinary explanations

the shared Christian story during the Renaissance

Church, artists, businesses and consumers all contributed to the great rebirth of culture

largely driven by the church and government institutions which we don’t necessarily want to recreate, right?

So how do we achieve the same effect?

The answer is sacred content.

I adopt what I believe in, and if the content is sacred, then it is beyond question.

An authority has determined these are sacred and therefore worthy

The Authority establishes a values framework, a ruling hierarchy directs and stewards the sacred content, and a host of intermediaries that carry it out to the faithful consumers.

We now have a strong distrust of authority, which has lost all legitimacy:

All around us there’s a collapse of the legitimacy of authorities, with much cynicism from the population. There’s never been a greater need for sacred content that can be trusted and deemed legitimate. How to achieve it without authorities? This is where we have to pivot our minds. We have to replace the dynamics of its creation within the authority with something else. This slide suggests an alternative:

We can create a values framework using collaborative culture techniques like community mythology projects. Out of these come sacred content that is legitimate because we created it according to shared values and a collective conscience. We have to put in place processes and rituals to establish, enshrine and communicate it.