And that's not just true for crypto, but also other areas of the law. Your best-known crypto decisions strongly assert that crypto is traceable. One way people try to make it less traceable is with mixers, and Tornado Cash was sanctioned by OFAC not too long ago. Do you think the legal reasoning was sound enough for similar sanctions to be applied to other mixers, or decentralized exchanges?

I don't know. I think there's been some discussion that people may litigate some of these things, so I can't comment, because those frequently do come to our courthouse. And I think there are certainly people opining on that, yes and no.

So much of what judges do is that we rely on the parties that are before us to tell us what's right and what's wrong. And then, you know, obviously, they'll have different views, and we make a decision based on what people say in front of us. Are you aware that some legal analysis of the Tornado Cash sanctions references your recent decision in a cryptocurrency sanctions case?

That's what good lawyers will always do. Even legislators might look at that as they try to think about where the gaps are. As a prosecutor I had a case where we sued three Chinese banks to give us their bank records, and it had never been done before. Afterwards, Congress passed a new law, using the decisions from judges in this court and the D. circuit court, the court above us. So I'm sure people look at prior decisions and try to apply them in the ways that they want to. Are there any misconceptions about how the law applies to crypto, or how your decisions should be interpreted, that you wish you could get across?

One misconception is that the judges can't understand this technology — we can. People have these views in two extremes. The lawyer's fundamental job is to take super complex and technical things and boil them down to very easily digestible arguments for a judge, for a jury, or whoever it might be.

The financial technology transformation is driving competition, creating consumer choice, and shaping the future of finance.

Hear from seven fintech leaders who are reshaping the future of finance, and join the inaugural Financial Technology Association Fintech Summit to learn more. Financial technology is breaking down barriers to financial services and delivering value to consumers, small businesses, and the economy. Fintech puts American consumers at the center of their finances and helps them manage their money responsibly.

From payment apps to budgeting and investing tools and alternative credit options, fintech makes it easier for consumers to pay for their purchases and build better financial habits. Fintech also arms small businesses with the financial tools for success, including low-cost banking services, digital accounting services, and expanded access to capital. We advocate for modernized financial policies and regulations that allow fintech innovation to drive competition in the economy and expand consumer choice.

Spots are still available for this hybrid event, and you can RSVP here to save your seat. Join us as we discuss how to shape the future of finance. In its broadest sense, Open Banking has created a secure and connected ecosystem that has led to an explosion of new and innovative solutions that benefit the customer, rapidly revolutionizing not just the banking industry but the way all companies do business.

Target benefits are delivered through speed, transparency, and security, and their impact can be seen across a diverse range of use cases.

Sharing financial data across providers can enable a customer individual or business to have real-time access to multiple bank accounts across multiple institutions all in one platform, saving time and helping consumers get a more accurate picture of their own finances before taking on debt, providing a more reliable indication than most lending guidelines currently do. Companies can also create carefully refined marketing profiles and therefore, finely tune their services to the specific need.

Open Banking platforms like Klarna Kosma also provide a unique opportunity for businesses to overlay additional tools that add real value for users and deepen their customer relationships. The increased transparency brought about by Open Banking brings a vast array of additional benefits, such as helping fraud detection companies better monitor customer accounts and identify problems much earlier.

The list of new value-add solutions continues to grow. The speed of business has never been faster than it is today. For small business owners, time is at a premium as they are wearing multiple hats every day. Macroeconomic challenges like inflation and supply chain issues are making successful money and cash flow management even more challenging.

This presents a tremendous opportunity that innovation in fintech can solve by speeding up money movement, increasing access to capital, and making it easier to manage business operations in a central place. Fintech offers innovative products and services where outdated practices and processes offer limited options. For example, fintech is enabling increased access to capital for business owners from diverse and varying backgrounds by leveraging alternative data to evaluate creditworthiness and risk models.

This can positively impact all types of business owners, but especially those underserved by traditional financial service models. When we look across the Intuit QuickBooks platform and the overall fintech ecosystem, we see a variety of innovations fueled by AI and data science that are helping small businesses succeed. By efficiently embedding and connecting financial services like banking, payments, and lending to help small businesses, we can reinvent how SMBs get paid and enable greater access to the vital funds they need at critical points in their journey.

Overall, we see fintech as empowering people who have been left behind by antiquated financial systems, giving them real-time insights, tips, and tools they need to turn their financial dreams into a reality. Innovations in payments and financial technologies have helped transform daily life for millions of people. People who are unbanked often rely on more expensive alternative financial products AFPs such as payday loans, money orders, and other expensive credit facilities that typically charge higher fees and interest rates, making it more likely that people have to dip into their savings to stay afloat.

A few examples include:. Mobile wallets - The unbanked may not have traditional bank accounts but can have verified mobile wallet accounts for shopping and bill payments.

Their mobile wallet identity can be used to open a virtual bank account for secure and convenient online banking. Minimal to no-fee banking services - Fintech companies typically have much lower acquisition and operating costs than traditional financial institutions. They are then able to pass on these savings in the form of no-fee or no-minimum-balance products to their customers.

This enables immigrants and other populations that may be underbanked to move up the credit lifecycle to get additional forms of credit such as auto, home and education loans, etc.

Entrepreneurs from every background, in every part of the world, should be empowered to start and scale global businesses. Most businesses still face daunting challenges with very basic matters. These are still very manually intensive processes, and they are barriers to entrepreneurship in the form of paperwork, PDFs, faxes, and forms. Stripe is working to solve these rather mundane and boring challenges, almost always with an application programming interface that simplifies complex processes into a few clicks.

Stripe powers nearly half a million businesses in rural America. The internet economy is just beginning to make a real difference for businesses of all sizes in all kinds of places. We are excited about this future. The way we make decisions on credit should be fair and inclusive and done in a way that takes into account a greater picture of a person.

Lenders can better serve their borrowers with more data and better math. Zest AI has successfully built a compliant, consistent, and equitable AI-automated underwriting technology that lenders can utilize to help make their credit decisions. While artificial intelligence AI systems have been a tool historically used by sophisticated investors to maximize their returns, newer and more advanced AI systems will be the key innovation to democratize access to financial systems in the future.

D espite privacy, ethics, and bias issues that remain to be resolved with AI systems, the good news is that as large r datasets become progressively easier to interconnect, AI and related natural language processing NLP technology innovations are increasingly able to equalize access. T he even better news is that this democratization is taking multiple forms. AI can be used to provide risk assessments necessary to bank those under-served or denied access. AI systems can also retrieve troves of data not used in traditional credit reports, including personal cash flow, payment applications usage, on-time utility payments, and other data buried within large datasets, to create fair and more accurate risk assessments essential to obtain credit and other financial services.

By expanding credit availability to historically underserved communities, AI enables them to gain credit and build wealth. Additionally, personalized portfolio management will become available to more people with the implementation and advancement of AI. Sophisticated financial advice and routine oversight, typically reserved for traditional investors, will allow individuals, including marginalized and low-income people, to maximize the value of their financial portfolios. Moreover, when coupled with NLP technologies, even greater democratization can result as inexperienced investors can interact with AI systems in plain English, while providing an easier interface to financial markets than existing execution tools.

Open finance technology enables millions of people to use the apps and services that they rely on to manage their financial lives — from overdraft protection, to money management, investing for retirement, or building credit. More than 8 in 10 Americans are now using digital finance tools powered by open finance. This is because consumers see something they like or want — a new choice, more options, or lower costs. What is open finance? At its core, it is about putting consumers in control of their own data and allowing them to use it to get a better deal.

When people can easily switch to another company and bring their financial history with them, that presents real competition to legacy services and forces everyone to improve, with positive results for consumers. For example, we see the impact this is having on large players being forced to drop overdraft fees or to compete to deliver products consumers want. We see the benefits of open finance first hand at Plaid, as we support thousands of companies, from the biggest fintechs, to startups, to large and small banks.

All are building products that depend on one thing - consumers' ability to securely share their data to use different services. Open finance has supported more inclusive, competitive financial systems for consumers and small businesses in the U.

and across the globe — and there is room to do much more. As an example, the National Consumer Law Consumer recently put out a new report that looked at consumers providing access to their bank account data so their rent payments could inform their mortgage underwriting and help build credit. This is part of the promise of open finance. At Plaid, we believe a consumer should have a right to their own data, and agency over that data, no matter where it sits.

This will be essential to securing benefits of open finance for consumers for many years to come. As AWS preps for its annual re:Invent conference, Adam Selipsky talks product strategy, support for hybrid environments, and the value of the cloud in uncertain economic times. Donna Goodison dgoodison is Protocol's senior reporter focusing on enterprise infrastructure technology, from the 'Big 3' cloud computing providers to data centers.

She previously covered the public cloud at CRN after 15 years as a business reporter for the Boston Herald. AWS is gearing up for re:Invent, its annual cloud computing conference where announcements this year are expected to focus on its end-to-end data strategy and delivering new industry-specific services.

Both prongs of that are important. But cost-cutting is a reality for many customers given the worldwide economic turmoil, and AWS has seen an increase in customers looking to control their cloud spending. By the way, they should be doing that all the time. The motivation's just a little bit higher in the current economic situation.

This interview has been edited and condensed for clarity. Besides the sheer growth of AWS, what do you think has changed the most while you were at Tableau? Were you surprised by anything? The number of customers who are now deeply deployed on AWS, deployed in the cloud, in a way that's fundamental to their business and fundamental to their success surprised me. There was a time years ago where there were not that many enterprise CEOs who were well-versed in the cloud.

It's not just about deploying technology. The conversation that I most end up having with CEOs is about organizational transformation. It is about how they can put data at the center of their decision-making in a way that most organizations have never actually done in their history. And it's about using the cloud to innovate more quickly and to drive speed into their organizations.

Those are cultural characteristics, not technology characteristics, and those have organizational implications about how they organize and what teams they need to have. It turns out that while the technology is sophisticated, deploying the technology is arguably the lesser challenge compared with how do you mold and shape the organization to best take advantage of all the benefits that the cloud is providing.

How has your experience at Tableau affected AWS and how you think about putting your stamp on AWS? I, personally, have just spent almost five years deeply immersed in the world of data and analytics and business intelligence, and hopefully I learned something during that time about those topics.

I'm able to bring back a real insider's view, if you will, about where that world is heading — data, analytics, databases, machine learning, and how all those things come together, and how you really need to view what's happening with data as an end-to-end story.

It's not about having a point solution for a database or an analytic service, it's really about understanding the flow of data from when it comes into your organization all the way through the other end, where people are collaborating and sharing and making decisions based on that data.

AWS has tremendous resources devoted in all these areas. Can you talk about the intersection of data and machine learning and how you see that playing out in the next couple of years? What we're seeing is three areas really coming together: You've got databases, analytics capabilities, and machine learning, and it's sort of like a Venn diagram with a partial overlap of those three circles.

There are areas of each which are arguably still independent from each other, but there's a very large and a very powerful intersection of the three — to the point where we've actually organized inside of AWS around that and have a single leader for all of those areas to really help bring those together. There's so much data in the world, and the amount of it continues to explode. We were saying that five years ago, and it's even more true today.

The rate of growth is only accelerating. It's a huge opportunity and a huge problem. A lot of people are drowning in their data and don't know how to use it to make decisions. Other organizations have figured out how to use these very powerful technologies to really gain insights rapidly from their data.

What we're really trying to do is to look at that end-to-end journey of data and to build really compelling, powerful capabilities and services at each stop in that data journey and then…knit all that together with strong concepts like governance. By putting good governance in place about who has access to what data and where you want to be careful within those guardrails that you set up, you can then set people free to be creative and to explore all the data that's available to them.

AWS has more than services now. Have you hit the peak for that or can you sustain that growth? We're not done building yet, and I don't know when we ever will be. We continue to both release new services because customers need them and they ask us for them and, at the same time, we've put tremendous effort into adding new capabilities inside of the existing services that we've already built.

We don't just build a service and move on. Inside of each of our services — you can pick any example — we're just adding new capabilities all the time. One of our focuses now is to make sure that we're really helping customers to connect and integrate between our different services. So those kinds of capabilities — both building new services, deepening our feature set within existing services, and integrating across our services — are all really important areas that we'll continue to invest in.

Do customers still want those fundamental building blocks and to piece them together themselves, or do they just want AWS to take care of all that? There's no one-size-fits-all solution to what customers want. It is interesting, and I will say somewhat surprising to me, how much basic capabilities, such as price performance of compute, are still absolutely vital to our customers.

But it's absolutely vital. Part of that is because of the size of datasets and because of the machine learning capabilities which are now being created. They require vast amounts of compute, but nobody will be able to do that compute unless we keep dramatically improving the price performance. We also absolutely have more and more customers who want to interact with AWS at a higher level of abstraction…more at the application layer or broader solutions, and we're putting a lot of energy, a lot of resources, into a number of higher-level solutions.

One of the biggest of those … is Amazon Connect, which is our contact center solution. In minutes or hours or days, you can be up and running with a contact center in the cloud.

At the beginning of the pandemic, Barclays … sent all their agents home. In something like 10 days, they got 6, agents up and running on Amazon Connect so they could continue servicing their end customers with customer service. We've built a lot of sophisticated capabilities that are machine learning-based inside of Connect. We can do call transcription, so that supervisors can help with training agents and services that extract meaning and themes out of those calls. We don't talk about the primitive capabilities that power that, we just talk about the capabilities to transcribe calls and to extract meaning from the calls.

It's really important that we provide solutions for customers at all levels of the stack. Given the economic challenges that customers are facing, how is AWS ensuring that enterprises are getting better returns on their cloud investments? Now's the time to lean into the cloud more than ever, precisely because of the uncertainty. We saw it during the pandemic in early , and we're seeing it again now, which is, the benefits of the cloud only magnify in times of uncertainty.

For example, the one thing which many companies do in challenging economic times is to cut capital expense. For most companies, the cloud represents operating expense, not capital expense.

You're not buying servers, you're basically paying per unit of time or unit of storage. That provides tremendous flexibility for many companies who just don't have the CapEx in their budgets to still be able to get important, innovation-driving projects done. Another huge benefit of the cloud is the flexibility that it provides — the elasticity, the ability to dramatically raise or dramatically shrink the amount of resources that are consumed.

You can only imagine if a company was in their own data centers, how hard that would have been to grow that quickly. The ability to dramatically grow or dramatically shrink your IT spend essentially is a unique feature of the cloud. These kinds of challenging times are exactly when you want to prepare yourself to be the innovators … to reinvigorate and reinvest and drive growth forward again. We've seen so many customers who have prepared themselves, are using AWS, and then when a challenge hits, are actually able to accelerate because they've got competitors who are not as prepared, or there's a new opportunity that they spot.

We see a lot of customers actually leaning into their cloud journeys during these uncertain economic times. Do you still push multi-year contracts, and when there's times like this, do customers have the ability to renegotiate?

Many are rapidly accelerating their journey to the cloud. Some customers are doing some belt-tightening. What we see a lot of is folks just being really focused on optimizing their resources, making sure that they're shutting down resources which they're not consuming.

You do see some discretionary projects which are being not canceled, but pushed out. Every customer is free to make that choice. But of course, many of our larger customers want to make longer-term commitments, want to have a deeper relationship with us, want the economics that come with that commitment.

We're signing more long-term commitments than ever these days. We provide incredible value for our customers, which is what they care about. That kind of analysis would not be feasible, you wouldn't even be able to do that for most companies, on their own premises.

So some of these workloads just become better, become very powerful cost-savings mechanisms, really only possible with advanced analytics that you can run in the cloud.

In other cases, just the fact that we have things like our Graviton processors and … run such large capabilities across multiple customers, our use of resources is so much more efficient than others. We are of significant enough scale that we, of course, have good purchasing economics of things like bandwidth and energy and so forth.

So, in general, there's significant cost savings by running on AWS, and that's what our customers are focused on. The margins of our business are going to … fluctuate up and down quarter to quarter. It will depend on what capital projects we've spent on that quarter. Obviously, energy prices are high at the moment, and so there are some quarters that are puts, other quarters there are takes.

The important thing for our customers is the value we provide them compared to what they're used to. And those benefits have been dramatic for years, as evidenced by the customers' adoption of AWS and the fact that we're still growing at the rate we are given the size business that we are.

That adoption speaks louder than any other voice. Do you anticipate a higher percentage of customer workloads moving back on premises than you maybe would have three years ago? Absolutely not. We're a big enough business, if you asked me have you ever seen X, I could probably find one of anything, but the absolute dominant trend is customers dramatically accelerating their move to the cloud.

Moving internal enterprise IT workloads like SAP to the cloud, that's a big trend. Creating new analytics capabilities that many times didn't even exist before and running those in the cloud. More startups than ever are building innovative new businesses in AWS. If the server receives a request other than one including an If- Range request-header field with an unsatisfiable Range request- header field that is, all of whose byte-range-spec values have a first-byte-pos value greater than the current length of the selected resource , it SHOULD return a response code of Requested range not satisfiable section The Content-Type entity-header field indicates the media type of the entity-body sent to the recipient or, in the case of the HEAD method, the media type that would have been sent had the request been a GET.

Media types are defined in section 3. An example of the field is. Further discussion of methods for identifying the media type of an entity is provided in section 7.

The Date general-header field represents the date and time at which the message was originated, having the same semantics as orig-date in RFC The field value is an HTTP-date, as described in section 3.

Origin servers MUST include a Date header field in all responses, except in these cases:. A received message that does not have a Date header field MUST be assigned one by the recipient if the message will be cached by that recipient or gatewayed via a protocol which requires a Date. An HTTP implementation without a clock MUST NOT cache responses without revalidating them on every use.

An HTTP cache, especially a shared cache, SHOULD use a mechanism, such as NTP [28] , to synchronize its clock with a reliable external standard. Clients SHOULD only send a Date header field in messages that include an entity-body, as in the case of the PUT and POST requests, and even then it is optional. A client without a clock MUST NOT send a Date header field in a request.

The HTTP-date sent in a Date header SHOULD NOT represent a date and time subsequent to the generation of the message. It SHOULD represent the best available approximation of the date and time of message generation, unless the implementation has no means of generating a reasonably accurate date and time. In theory, the date ought to represent the moment just before the entity is generated. In practice, the date can be generated at any time during the message origination without affecting its semantic value.

Some origin server implementations might not have a clock available. An origin server without a clock MUST NOT assign Expires or Last- Modified values to a response, unless these values were associated with the resource by a system or user with a reliable clock.

It MAY assign an Expires value that is known, at or before server configuration time, to be in the past this allows "pre-expiration" of responses without storing separate Expires values for each resource. The ETag response-header field provides the current value of the entity tag for the requested variant. The headers used with entity tags are described in sections The entity tag MAY be used for comparison with other entities from the same resource see section The Expect request-header field is used to indicate that particular server behaviors are required by the client.

A server that does not understand or is unable to comply with any of the expectation values in the Expect field of a request MUST respond with appropriate error status. The server MUST respond with a Expectation Failed status if any of the expectations cannot be met or, if there are other problems with the request, some other 4xx status.

This header field is defined with extensible syntax to allow for future extensions. If a server receives a request containing an Expect field that includes an expectation-extension that it does not support, it MUST respond with a Expectation Failed status. Comparison of expectation values is case-insensitive for unquoted tokens including the continue token , and is case-sensitive for quoted-string expectation-extensions.

However, the Expect request-header itself is end-to-end; it MUST be forwarded if the request is forwarded. See section 8. A stale cache entry may not normally be returned by a cache either a proxy cache or a user agent cache unless it is first validated with the origin server or with an intermediate cache that has a fresh copy of the entity.

The presence of an Expires field does not imply that the original resource will change or cease to exist at, before, or after that time. The format is an absolute date and time as defined by HTTP-date in section 3. To mark a response as "already expired," an origin server sends an Expires date that is equal to the Date header value. See the rules for expiration calculations in section To mark a response as "never expires," an origin server sends an Expires date approximately one year from the time the response is sent.

The presence of an Expires header field with a date value of some time in the future on a response that otherwise would by default be non-cacheable indicates that the response is cacheable, unless indicated otherwise by a Cache-Control header field section The From request-header field, if given, SHOULD contain an Internet e-mail address for the human user who controls the requesting user agent. The address SHOULD be machine-usable, as defined by "mailbox" in RFC [9] as updated by RFC [8] :.

This header field MAY be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It SHOULD NOT be used as an insecure form of access protection. The interpretation of this field is that the request is being performed on behalf of the person given, who accepts responsibility for the method performed.

In particular, robot agents SHOULD include this header so that the person responsible for running the robot can be contacted if problems occur on the receiving end.

The Internet e-mail address in this field MAY be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original issuer's address SHOULD be used. The client SHOULD NOT send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's security policy. It is strongly recommended that the user be able to disable, enable, and modify the value of this field at any time prior to a request.

The Host request-header field specifies the Internet host and port number of the resource being requested, as obtained from the original URI given by the user or referring resource generally an HTTP URL,. as described in section 3. The Host field value MUST represent the naming authority of the origin server or gateway given by the original URL.

A "host" without any trailing port information implies the default port for the service requested e. If the requested URI does not include an Internet host name for the service being requested, then the Host header field MUST be given with an empty value. See sections 5. The If-Match request-header field is used with a method to make it conditional. A client that has one or more entities previously obtained from the resource can verify that one of those entities is current by including a list of their associated entity tags in the If-Match header field.

Entity tags are defined in section 3. The purpose of this feature is to allow efficient updates of cached information with a minimum amount of transaction overhead.

It is also used, on updating requests, to prevent inadvertent modification of the wrong version of a resource. and any current entity exists for that resource, then the server MAY perform the requested method as if the If-Match header field did not exist. A server MUST use the strong comparison function see section This behavior is most useful when the client wants to prevent an updating method, such as PUT, from modifying a resource that has changed since the client last retrieved it.

If the request would, without the If-Match header field, result in anything other than a 2xx or status, then the If-Match header MUST be ignored. A request intended to update a resource e. This allows the user to indicate that they do not wish the request to be successful if the resource has been changed without their knowledge. The result of a request having both an If-Match header field and either an If-None-Match or an If-Modified-Since header fields is undefined by this specification.

The If-Modified-Since request-header field is used with a method to make it conditional: if the requested variant has not been modified since the time specified in this field, an entity will not be returned from the server; instead, a not modified response will be returned without any message-body. A GET method with an If-Modified-Since header and no Range header requests that the identified entity be transferred only if it has been modified since the date given by the If-Modified-Since header.

The algorithm for determining this includes the following cases:. The result of a request having both an If-Modified-Since header field and either an If-Match or an If-Unmodified-Since header fields is undefined by this specification. The If-None-Match request-header field is used with a method to make it conditional. A client that has one or more entities previously obtained from the resource can verify that none of those entities is current by including a list of their associated entity tags in the If-None-Match header field.

It is also used to prevent a method e. PUT from inadvertently modifying an existing resource when the client believes that the resource does not exist. Instead, if the request method was GET or HEAD, the server SHOULD respond with a Not Modified response, including the cache- related header fields particularly ETag of one of the entities that matched. For all other request methods, the server MUST respond with a status of Precondition Failed.

The weak comparison function can only be used with GET or HEAD requests. If none of the entity tags match, then the server MAY perform the requested method as if the If-None-Match header field did not exist, but MUST also ignore any If-Modified-Since header field s in the request.

That is, if no entity tags match, then the server MUST NOT return a Not Modified response. If the request would, without the If-None-Match header field, result in anything other than a 2xx or status, then the If-None-Match header MUST be ignored.

This feature is intended to be useful in preventing races between PUT operations. The result of a request having both an If-None-Match header field and either an If-Match or an If-Unmodified-Since header fields is undefined by this specification. If a client has a partial copy of an entity in its cache, and wishes to have an up-to-date copy of the entire entity in its cache, it could use the Range request-header with a conditional GET using either or both of If-Unmodified-Since and If-Match.

However, if the condition fails because the entity has been modified, the client would then have to make a second request to obtain the entire current entity-body.

The If-Range header allows a client to "short-circuit" the second request. If the client has no entity tag for an entity, but does have a Last- Modified date, it MAY use that date in an If-Range header.

The server can distinguish between a valid HTTP-date and any form of entity-tag by examining no more than two characters. The If-Range header SHOULD only be used together with a Range header, and MUST be ignored if the request does not include a Range header, or if the server does not support the sub-range operation.

If the entity tag given in the If-Range header matches the current entity tag for the entity, then the server SHOULD provide the specified sub-range of the entity using a Partial content response. If the entity tag does not match, then the server SHOULD return the entire entity using a OK response. The If-Unmodified-Since request-header field is used with a method to make it conditional.

If the requested resource has not been modified since the time specified in this field, the server SHOULD perform the requested operation as if the If-Unmodified-Since header were not present. If the requested variant has been modified since the specified time, the server MUST NOT perform the requested operation, and MUST return a Precondition Failed. If the request normally i. The result of a request having both an If-Unmodified-Since header field and either an If-None-Match or an If-Modified-Since header fields is undefined by this specification.

The Last-Modified entity-header field indicates the date and time at which the origin server believes the variant was last modified. The exact meaning of this header field depends on the implementation of the origin server and the nature of the original resource.

For files, it may be just the file system last-modified time. For entities with dynamically included parts, it may be the most recent of the set of last-modify times for its component parts. For database gateways, it may be the last-update time stamp of the record. For virtual objects, it may be the last time the internal state changed.

An origin server MUST NOT send a Last-Modified date which is later than the server's time of message origination. In such cases, where the resource's last modification would indicate some time in the future, the server MUST replace that date with the message origination date. An origin server SHOULD obtain the Last-Modified value of the entity as close as possible to the time that it generates the Date value of its response.

This allows a recipient to make an accurate assessment of the entity's modification time, especially if the entity changes near the time that the response is generated. The Location response-header field is used to redirect the recipient to a location other than the Request-URI for completion of the request or identification of a new resource. For Created responses, the Location is that of the new resource which was created by the request.

For 3xx responses, the location SHOULD indicate the server's preferred URI for automatic redirection to the resource. The field value consists of a single absolute URI. The Max-Forwards request-header field provides a mechanism with the TRACE section 9. This can be useful when the client is attempting to trace a request chain which appears to be failing or looping in mid-chain.

The Max-Forwards value is a decimal integer indicating the remaining number of times this request message may be forwarded. Each proxy or gateway recipient of a TRACE or OPTIONS request containing a Max-Forwards header field MUST check and update its value prior to forwarding the request.

If the received value is zero 0 , the recipient MUST NOT forward the request; instead, it MUST respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message MUST contain an updated Max-Forwards field with a value decremented by one 1. The Max-Forwards header field MAY be ignored for all other methods defined by this specification and for any extension methods for which it is not explicitly referred to as part of that method definition.

All pragma directives specify optional behavior from the viewpoint of the protocol; however, some systems MAY require that behavior be consistent with the directives. When the no-cache directive is present in a request message, an application SHOULD forward the request toward the origin server even if it has a cached copy of what is being requested. This pragma directive has the same semantics as the no-cache cache-directive see section It is not possible to specify a pragma for a specific recipient; however, any pragma directive not relevant to a recipient SHOULD be ignored by that recipient.

No new Pragma directives will be defined in HTTP. The Proxy-Authenticate response-header field MUST be included as part of a Proxy Authentication Required response. The field value consists of a challenge that indicates the authentication scheme and parameters applicable to the proxy for this Request-URI. The HTTP access authentication process is described in "HTTP Authentication: Basic and Digest Access Authentication" [43]. Unlike WWW-Authenticate, the Proxy-Authenticate header field applies only to the current connection and SHOULD NOT be passed on to downstream clients.

However, an intermediate proxy might need to obtain its own credentials by requesting them from the downstream client, which in some circumstances will appear as if the proxy is forwarding the Proxy-Authenticate header field. The Proxy-Authorization request-header field allows the client to identify itself or its user to a proxy which requires authentication. Unlike Authorization, the Proxy-Authorization header field applies only to the next outbound proxy that demanded authentication using the Proxy- Authenticate field.

When multiple proxies are used in a chain, the. Proxy-Authorization header field is consumed by the first outbound proxy that was expecting to receive credentials. A proxy MAY relay the credentials from the client request to the next proxy if that is the mechanism by which the proxies cooperatively authenticate a given request.

Since all HTTP entities are represented in HTTP messages as sequences of bytes, the concept of a byte range is meaningful for any HTTP entity. However, not all clients and servers need to support byte- range operations. Byte range specifications in HTTP apply to the sequence of bytes in the entity-body not necessarily the same as the message-body.

A byte range operation MAY specify a single range of bytes, or a set of ranges within a single entity. The first-byte-pos value in a byte-range-spec gives the byte-offset of the first byte in a range. The last-byte-pos value gives the byte-offset of the last byte in the range; that is, the byte positions specified are inclusive.

Byte offsets start at zero. If the last-byte-pos value is present, it MUST be greater than or equal to the first-byte-pos in that byte-range-spec, or the byte- range-spec is syntactically invalid.

The recipient of a byte-range- set that includes one or more syntactically invalid byte-range-spec values MUST ignore the header field that includes that byte-range- set. If the last-byte-pos value is absent, or if the value is greater than or equal to the current length of the entity-body, last-byte-pos is taken to be equal to one less than the current length of the entity- body in bytes.

By its choice of last-byte-pos, a client can limit the number of bytes retrieved without knowing the size of the entity. A suffix-byte-range-spec is used to specify the suffix of the entity-body, of a length given by the suffix-length value. That is, this form specifies the last N bytes of an entity-body. If the entity is shorter than the specified suffix-length, the entire entity-body is used.

If a syntactically valid byte-range-set includes at least one byte- range-spec whose first-byte-pos is less than the current length of the entity-body, or at least one suffix-byte-range-spec with a non- zero suffix-length, then the byte-range-set is satisfiable. Otherwise, the byte-range-set is unsatisfiable.

If the byte-range-set is unsatisfiable, the server SHOULD return a response with a status of Requested range not satisfiable. Otherwise, the server SHOULD return a response with a status of Partial Content containing the satisfiable ranges of the entity-body. HTTP retrieval requests using conditional or unconditional GET methods MAY request one or more sub-ranges of the entity, instead of the entire entity, using the Range request header, which applies to the entity returned as the result of the request:.

A server MAY ignore the Range header. If the server supports the Range header and the specified range or ranges are appropriate for the entity:. In some cases, it might be more appropriate to use the If-Range header see section If a proxy that supports ranges receives a Range request, forwards the request to an inbound server, and receives an entire entity in reply, it SHOULD only return the requested range to its client.

It SHOULD store the entire received response in its cache if that is consistent with its cache allocation policies. The Referer[sic] request-header field allows the client to specify, for the server's benefit, the address URI of the resource from which the Request-URI was obtained the "referrer", although the header field is misspelled. The Referer request-header allows a server to generate lists of back-links to resources for interest, logging, optimized caching, etc.

It also allows obsolete or mistyped links to be traced for maintenance. The Referer field MUST NOT be sent if the Request-URI was obtained from a source that does not have its own URI, such as input from the user keyboard. If the field value is a relative URI, it SHOULD be interpreted relative to the Request-URI. The URI MUST NOT include a fragment.

The Retry-After response-header field can be used with a Service Unavailable response to indicate how long the service is expected to be unavailable to the requesting client.

This field MAY also be used with any 3xx Redirection response to indicate the minimum time the user-agent is asked wait before issuing the redirected request. The value of this field can be either an HTTP-date or an integer number of seconds in decimal after the time of the response.

The Server response-header field contains information about the software used by the origin server to handle the request. The field can contain multiple product tokens section 3.

The product tokens are listed in order of their significance for identifying the application. If the response is being forwarded through a proxy, the proxy application MUST NOT modify the Server response-header. Instead, it SHOULD include a Via field as described in section The TE request-header field indicates what extension transfer-codings it is willing to accept in the response and whether or not it is willing to accept trailer fields in a chunked transfer-coding.

The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked transfer-coding, as defined in section 3. This keyword is reserved for use with transfer-coding values even though it does not itself represent a transfer-coding.

The TE header field only applies to the immediate connection. Therefore, the keyword MUST be supplied within a Connection header field section A server tests whether a transfer-coding is acceptable, according to a TE field, using these rules:. If the TE field-value is empty or if no TE field is present, the only transfer-coding is "chunked".

A message with no transfer-coding is always acceptable. The Trailer general field value indicates that the given set of header fields is present in the trailer of a message encoded with chunked transfer-coding. Doing so allows the recipient to know which header fields to expect in the trailer.

If no Trailer header field is present, the trailer SHOULD NOT include any header fields. See section 3. Message header fields listed in the Trailer header field MUST NOT include the following header fields:. The Transfer-Encoding general-header field indicates what if any type of transformation has been applied to the message body in order to safely transfer it between the sender and the recipient.

This differs from the content-coding in that the transfer-coding is a property of the message, not of the entity. Transfer-codings are defined in section 3. An example is:. If multiple encodings have been applied to an entity, the transfer- codings MUST be listed in the order in which they were applied. The Upgrade general-header allows the client to specify what additional communication protocols it supports and would like to use if the server finds it appropriate to switch protocols.

The server MUST use the Upgrade header field within a Switching Protocols response to indicate which protocol s are being switched. The Upgrade header field only applies to switching application-layer protocols upon the existing transport-layer connection. Upgrade cannot be used to insist on a protocol change; its acceptance and use by the server is optional. The capabilities and nature of the application-layer communication after the protocol change is entirely dependent upon the new protocol chosen, although the first action after changing the protocol MUST be a response to the initial HTTP request containing the Upgrade header field.

The Upgrade header field only applies to the immediate connection. Therefore, the upgrade keyword MUST be supplied within a Connection header field section The Upgrade header field cannot be used to indicate a switch to a protocol on a different connection.

For that purpose, it is more appropriate to use a , , , or redirection response. This specification only defines the protocol name "HTTP" for use by the family of Hypertext Transfer Protocols, as defined by the HTTP version rules of section 3. Any token can be used as a protocol name; however, it will only be useful if both the client and server associate the name with the same protocol. The User-Agent request-header field contains information about the user agent originating the request.

This is for statistical purposes, the tracing of protocol violations, and automated recognition of user agents for the sake of tailoring responses to avoid particular user agent limitations. User agents SHOULD include this field with requests.

For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who receives the entity. The Accept request-header field can be used to specify certain media types which are acceptable for the response. Accept headers can be used to indicate that the request is specifically limited to a small set of desired types, as in the case of a request for an in-line image.

The media-range MAY include media type parameters that are applicable to that range. Each media-range MAY be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative quality factor. The first "q" parameter if any separates the media-range parameter s from the accept-params.

Quality factors allow the user or user agent to indicate the relative degree of preference for that media-range, using the qvalue scale from 0 to 1 section 3. If no Accept header field is present, then it is assumed that the client accepts all media types. If an Accept header field is present, and if the server cannot send a response which is acceptable according to the combined Accept field value, then the server SHOULD send a not acceptable response.

Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies to a given type, the most specific reference has precedence. For example,. The media type quality factor associated with a given type is determined by finding the media range with the highest precedence which matches that type.

The Accept-Charset request-header field can be used to indicate what character sets are acceptable for the response. This field allows clients capable of understanding more comprehensive or special- purpose character sets to signal that capability to a server which is capable of representing documents in those character sets.

Character set values are described in section 3. Each charset MAY be given an associated quality value which represents the user's preference for that charset. An example is. If no Accept-Charset header is present, the default is that any character set is acceptable.

If an Accept-Charset header is present, and if the server cannot send a response which is acceptable according to the Accept-Charset header, then the server SHOULD send an error response with the not acceptable status code, though the sending of an unacceptable response is also allowed. The Accept-Encoding request-header field is similar to Accept, but restricts the content-codings section 3. A server tests whether a content-coding is acceptable, according to an Accept-Encoding field, using these rules:.

If an Accept-Encoding field is present in a request, and if the server cannot send a response which is acceptable according to the Accept-Encoding header, then the server SHOULD send an error response with the Not Acceptable status code.

If no Accept-Encoding field is present in a request, the server MAY assume that the client will accept any content coding. In this case, if "identity" is one of the available content-codings, then the server SHOULD use the "identity" content-coding, unless it has additional information that a different content-coding is meaningful to the client. The Accept-Language request-header field is similar to Accept, but restricts the set of natural languages that are preferred as a response to the request.

Language tags are defined in section 3. Each language-range MAY be given an associated quality value which represents an estimate of the user's preference for the languages specified by that range. would mean: "I prefer Danish, but will accept British English and other types of English. The language quality factor assigned to a language-tag by the Accept-Language field is the quality value of the longest language- range in the field that matches the language-tag.

If no language- range in the field matches the tag, the language quality factor assigned is 0. If no Accept-Language header is present in the request, the server. SHOULD assume that all languages are equally acceptable.

If an Accept-Language header is present, then all languages which are assigned a quality factor greater than 0 are acceptable.

It might be contrary to the privacy expectations of the user to send an Accept-Language header with the complete linguistic preferences of the user in every request. For a discussion of this issue, see section As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice of linguistic preference available to the user.

If the choice is not made available, then the Accept-Language header field MUST NOT be given in the request. The directives specify behavior intended to prevent caches from adversely interfering with the request or response.

These directives typically override the default caching algorithms. Cache directives are unidirectional in that the presence of a directive in a request does not imply that the same directive is to be given in the response. It is not possible to specify a cache- directive for a specific cache. When a directive appears without any 1 field-name parameter, the directive applies to the entire request or response. When such a directive appears with a 1 field-name parameter, it applies only to the named field or fields, and not to the rest of the request or response.

By default, a response is cacheable if the requirements of the request method, request header fields, and the response status indicate that it is cacheable. Section The following Cache-Control response directives allow an origin server to override the default cacheability of a response:. Note: This usage of the word private only controls where the response may be cached, and cannot ensure the privacy of the message content. The expiration time of an entity MAY be specified by the origin server using the Expires header see section Alternatively, it MAY be specified using the max-age directive in a response.

When the max-age cache-control directive is present in a cached response, the response is stale if its current age is greater than the age value given in seconds at the time of a new request for that resource. The max-age directive on a response implies that the response is cacheable i. If a response includes both an Expires header and a max-age directive, the max-age directive overrides the Expires header, even if the Expires header is more restrictive.

Note: An origin server might wish to use a relatively new HTTP cache control feature, such as the "private" directive, on a network including older caches that do not understand that feature. The origin server will need to combine the new feature with an Expires field whose value is less than or equal to the Date value. This will prevent older caches from improperly caching the response. Note that most older caches, not compliant with this specification, do not implement any cache-control directives.

Other directives allow a user agent to modify the basic expiration mechanism. These directives MAY be specified on a request:. If a cache returns a stale response, either because of a max-stale directive on a request, or because the cache is configured to override the expiration time of a response, the cache MUST attach a Warning header to the stale response, using Warning Response is stale.

A cache MAY be configured to return stale responses without validation, but only if this does not conflict with any "MUST"-level requirements concerning cache validation e. If both the new request and the cached entry include "max-age" directives, then the lesser of the two values is used for determining the freshness of the cached entry for that request. Sometimes a user agent might want or need to insist that a cache revalidate its cache entry with the origin server and not just with the next cache along the path to the origin server , or to reload its cache entry from the origin server.

End-to-end revalidation might be necessary if either the cache or the origin server has overestimated the expiration time of the cached response. End-to-end reload may be necessary if the cache entry has become corrupted for some reason.

End-to-end revalidation may be requested either when the client does not have its own local cached copy, in which case we call it "unspecified end-to-end revalidation", or when the client does have a local cached copy, in which case we call it "specific end-to-end revalidation.

The client can specify these three kinds of action using Cache- Control request directives:. The Cache-Control header field can be extended through the use of one or more cache-extension tokens, each with an optional assigned value.

Informational extensions those which do not require a change in cache behavior MAY be added without changing the semantics of other directives. Behavioral extensions are designed to work by acting as modifiers to the existing base of cache directives. Both the new directive and the standard directive are supplied, such that applications which do not understand the new directive will default to the behavior specified by the standard directive, and those that understand the new directive will recognize it as modifying the requirements associated with the standard directive.

In this way, extensions to the cache-control directives can be made without requiring changes to the base protocol. This extension mechanism depends on an HTTP cache obeying all of the cache-control directives defined for its native HTTP-version, obeying certain extensions, and ignoring all directives that it does not understand.

For example, consider a hypothetical new response directive called community which acts as a modifier to the private directive. We define this new directive to mean that, in addition to any non-shared cache, any cache which is shared only by members of the community named within its value may cache the response.

An origin server wishing to allow the UCI community to use an otherwise private response in their shared cache s could do so by including. A cache seeing this header field will act correctly even if the cache does not understand the community cache-extension, since it will also see and understand the private directive and thus default to the safe behavior. The Connection general-header field allows the sender to specify options that are desired for that particular connection and MUST NOT be communicated by proxies over further connections.

Connection options are signaled by the presence of a connection-token in the Connection header field, not by any corresponding additional header field s , since the additional header field may not be sent if there are no parameters associated with that connection option.

Message headers listed in the Connection header MUST NOT include end-to-end headers, such as Cache-Control. See section The Content-Encoding entity-header field is used as a modifier to the media-type. When present, its value indicates what additional content codings have been applied to the entity-body, and thus what decoding mechanisms must be applied in order to obtain the media-type referenced by the Content-Type header field.

Content-Encoding is primarily used to allow a document to be compressed without losing the identity of its underlying media type. Content codings are defined in section 3. An example of its use is. The content-coding is a characteristic of the entity identified by the Request-URI. Typically, the entity-body is stored with this encoding and is only decoded before rendering or analogous usage. However, a non-transparent proxy MAY modify the content-coding if the new coding is known to be acceptable to the recipient, unless the "no-transform" cache-control directive is present in the message.

If the content-coding of an entity is not "identity", then the response MUST include a Content-Encoding entity-header section If the content-coding of an entity in a request message is not acceptable to the origin server, the server SHOULD respond with a status code of Unsupported Media Type.

If multiple encodings have been applied to an entity, the content codings MUST be listed in the order in which they were applied. Additional information about the encoding parameters MAY be provided by other entity-header fields not defined by this specification.

The Content-Language entity-header field describes the natural language s of the intended audience for the enclosed entity. Note that this might not be equivalent to all the languages used within the entity-body. The primary purpose of Content-Language is to allow a user to identify and differentiate entities according to the user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate field is.

If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language it is intended.

The server MUST respond with a Expectation Failed status if any of the expectations cannot be met or, if there are other problems with the request, some other 4xx status. Those copying decide how much to invest, and whether to copy some or all of the trades that a particular trader or tipster opens. NFT: Mount Rushmore of NY Sports. For example, fintech is enabling increased access to capital for business owners from diverse and varying backgrounds by leveraging alternative data to evaluate creditworthiness and risk models. Only professional clients or professional accounts are now permitted to trade binaries with regulated firms. Steven A. An origin server wishing to allow the UCI community to use an otherwise private response in their shared cache s could do so by including.

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