Blockchain Attacks and the Fight for Immutability

Perkins Coie

Perkins Coie

The Ethereum Classic blockchain was the victim of a 51% attack (often called a majority or Sybil attack) on January 5, 2019 that reorganized portions of the blockchain and allowed the attackers to double-spend 219,500 ETC ($1.1 million). As a result of this attack, and similar majority attacks over the past year, the concept of immutability within blockchain technology has been revealed to be a potentially costly oversimplification. If determined foes can alter a blockchain, even temporarily, then many blockchain systems may be more fragile than is commonly perceived. These attacks show that protecting the permanence of data on the blockchain cannot be assumed, but instead is an evolving challenge and an important consideration for those who design, manage, participate in and rely upon blockchain networks for their businesses.

This update presents a more nuanced understanding of blockchain immutability, along with providing a practical understanding of mining algorithms, market trends and how they relate to the efficacy of blockchains serving as immutable repositories of transaction data. The update concludes by summarizing some of the ways that market participants are using legal solutions to mitigate risks and respond to attacks.

Describing Immutability for Public Blockchains

When applied to blockchains, the term “immutability” is relative. In practice, immutability often means different things to different people, and not all blockchains are created equal when it comes to the irreversibility of transactions. Most people can agree that data permanence and auditability are a critical part of the design for public-permissionless blockchains. For example, it is the driving force behind Bitcoin and many other virtual currencies that need to make sure that the same virtual currency is never spent more than once, duplicated or falsified (i.e., avoiding the double-spend problem). To accomplish this goal, virtual currency protocols utilize various hash functions[1] to link blocks of transactions and implement a competitive (and often resource intensive) mining process to validate each consecutive block on the ledger. The combination of these methods allows for users to have certainty that each block follows orderly from the last without missing any transaction previously written to the chain.

Many public blockchains, particularly Bitcoin and Ethereum, have largely managed to avoid catastrophic cybersecurity issues related to their core function because their core architecture is robust. An element of this sturdiness comes from several sources, including their well-understood and simple hashing algorithms (SHA-256 for Bitcoin and KECCAK-256 for Ethereum), the number of nodes in operation, and the straightforward method by which mining and validation is accomplished.[2] For Bitcoin, Ethereum and many other public blockchains that rely on proof-of-work mining algorithms, any node can directly participate in mining. Further, each node’s expected revenue from mining is proportional to its mining power—also known as “hashrate.” These activities combine to provide a robust and (usually) immutable system that ensures a significant computational effort must be employed to validate the next block in the chain. This computational cost of mining is also magnified the deeper you go into the chain, making it exponentially more resource intensive for any one miner (or group of miners) to expend enough computing power to change older transactions in historical blocks.

Until recently, the most commonly perceived threats to virtual currencies were not associated with the security of the blockchain protocols themselves. Instead, the greatest risks (outside of losing your private key) appeared to be from cybercriminals who, through hacking, social engineering or other means, gained access to exchange accounts or other digital wallets outside of the blockchain itself.

Majority Attacks, Block Reorganizations and Eclipse Attacks

Generally, a participant’s proportion of the total network hashrate determines the likelihood that it will decide the next block in the chain (and therefore decide the current shared truth among all participants in the network). However, if a participant (or group of participants) gains a sufficient proportion of the total hashrate (i.e., a 51% majority of the network resources), it can undermine the integrity of the network by reordering blocks, or otherwise altering the shared truth through a number of attack vectors. This potential weakness is inherent in many blockchains built on proof-of-work mining algorithms, and that is key reason that blockchain developers support a diverse and distributed hashrate pool.

If attackers can control 51% of the total network hashrate, there are many paths at their disposal to damage the network. Under certain conditions, attackers can build their own chain faster than the actual network and can broadcast their false version in a manner that the network accepts as real. During the time that the attackers have control, they can reverse any transaction that they submit or prevent transactions from being included in a block. Attackers can also reorder subsequent transactions (i.e., block reorganizations) that change past transactions in historic blocks that have already been confirmed.

Fortunately, there are things that attackers cannot do when they control 51% of the hashpower of a blockchain network. Generally, they cannot change the main parameters of the network within the core protocol. It also becomes exponentially more difficult to change older blocks the further into the past you go. For better or worse, many digital assets today are built on existing blockchain networks (e.g., ERC-20 standard digital assets on Ethereum). This concentration is a double-edged sword. On one hand, it means that young blockchain projects that use an ERC-20 token are relatively safe in relying on Ethereum hashpower to protect their transactions. On the other hand, it means that if Ethereum (the underlying blockchain network) is compromised, all other digital assets built on the blockchain network will be similarly affected.

To be clear, majority attacks are not the only attacks that blockchain networks face. There are many other well-documented and researched attack vectors on public blockchains. One other style of attack that warrants mention is an eclipse attack because such an attack does not rely on hashrate to execute successfully. An eclipse attack occurs when an attacker identifies the specific set of nodes on a blockchain network that the victim utilizes to monitor and commit transactions (Bitcoin and Ethereum connect with 8 or 13 nodes respectively). Once these nodes are identified, the attacker isolates its victim by hijacking the connecting nodes and impersonating the nodes in future transactions. A successful eclipse attack allows the attacker to dictate its own version of the truth to the victim without expending computational resources on a majority attack (i.e., eclipsing the victim’s access to the broader network).

Current Mining Pools, ASICs Providers and Hashrate Markets

Collectivized mining operations (i.e., mining pools) that pool hashrate for larger and more predictable payouts have existed since the early days of Bitcoin. These operations provide a user-friendly way for ordinary people to contribute (or purchase) hashrate and collaboratively mine without the difficulties associated with setting up and maintaining their own node on a blockchain network.

Because mining pools concentrate hashrate in the hands of pool operators, if they reach the 51% threshold hashrate they could potentially pose a threat to blockchain networks. In practice, however, mining pools are dependent on the many individual miners who participate in the pool, and who may move elsewhere if they disagree with the activities of the mining pool operators. This provides a reputational check on mining pools being used to attack the network. Some mining pools today have also shifted their focus towards other profit generating activities (e.g., “generalized mining” or “staking”) and have ceded significant amounts of the overall hashrate on blockchain networks to other participants.

Network Participants


Network Security Advantages

Network Security Disadvantages

Mining Pools

Aggregate individual miners for consistent profit.

Pool managers make it easier for hashrate to transition during upgrades to the network. Reputational checks on activity.

Centralization and concentration of hashpower, can influence network decisions and self-deal.

ASIC Providers

Develop, use and sell dedicated mining hardware.

Contributes to significant increases in overall network hashpower. Competition can check influence.

Centralization and concentration of hashpower can cause short-term network hashpower imbalances, particularly if provider is mining using ASICs that are not available to the public. New ASIC products can harm the market and hurt consumer mining in particular.

Cloud Miners/Hashrate Rental Markets

Provide remote access to mining resources for a fee.

Trivializes network resource access and increases efficiency of entire mining market. Supports broader competition among service providers and reputation is still important.

Centralization and concentration of hashpower, increases access to network resources and broadens potential attack sources.

Figure 1. Network Advantages and Disadvantages for Mining Participants

Increased competition for mining rewards has driven the creation of a market for specialized mining hardware (e.g., application-specific integrated circuits or ASICs) designed to outcompete traditional hardware (e.g., ordinary computer CPUs and GPUs). Companies that specialize in the production, use and eventual sale of ASICs are among the largest contributors of hashrate and consequently may wield a disproportionate level of influence over the technical direction and security of large blockchain networks. Increased attention has been drawn to the question of whether large ASIC mining organizations may assert leverage over blockchain developers and their communities in a way that influences which blockchains are supported through hashpower and consequently which networks are most secure.

Among other developments in the mining community is the growth of hashrate rental marketplaces. Hashrate rental markets allow customers to buy and sell hashpower for a fee and potentially trivialize the difficulty of gaining access to blockchain network resources. As a positive, these efforts further decentralize network hashpower and may diminish the influence of large blockchain mining organizations and their ASICs. Hashrate rental markets have also allowed for greater transparency into the cost to maintain a majority attack against various blockchain networks with some shocking results. However, some experts point to the recent surge of majority attacks on some of the largest blockchain networks that may be the result of hashrate markets.

Recent Attacks, Public Attention and Market Response

The convergence of efforts by some market participants to exploit hashrate and/or compromise blockchain networks has gained increased public attention in the last year. In May 2018, Bitcoin Gold was majority attacked resulting in $18 million in damages. Commentators predicate the attack on Bitcoin Gold making fundamental changes to its core architecture designed to support ASIC resistance. These efforts inadvertently caused Bitcoin Gold to have a relatively low hashrate to support the network, and this was exploited by the attack. Currently, some websites list the cost of conducting a majority attack against Bitcoin Gold at only $297 per hour. In December 2018, Vertcoin was subject to a majority attack that resulted in $100,000 in double-spends. Vertcoin was exploited in the same way as Bitcoin Gold, where the attackers initiated double-spends by spending virtual currency on the main chain and then publishing their own version of the chain that reorganized or removed the previous transactions, thereby returning their previously spent virtual currency. The most recent high-profile example of a majority attack occurred on the Ethereum Classic blockchain, which resulted in the suspension of trading on several major centralized exchanges and caused millions of dollars in damages and losses.

In each instance, attackers relied on virtual currency exchanges to escape with their ill-gotten gains. As a result, these exchanges have stepped-up measures to monitor anomalous blockchain network activity and have in some instances delisted attack-prone virtual currencies. Developers are also taking steps to improve security. During the recent Ethereum Classic attack, developers encouraged mining pools to take matters into their own hands by increasing confirmation times, thereby making deep blockchain reorganizations more difficult to accomplish. While these activities help address some of the short-term impacts of majority attacks, they do not deal with the broader systemic problem.

Although public attention on majority attacks has increased, blockchain developers have always known about the risk of majority attacks inherent in the blockchain model. Accordingly, some developers have designed processes to combat or avoid this attack vector altogether. For example, some public blockchains do not rely on proof-of-work mining algorithms for consensus and are therefore generally able to avoid hashrate concentration risks (but not necessarily majority attacks). More novel methods of combatting majority attacks are starting to crop up as well. Some companies are researching and developing products designed to combat the economic incentives driving majority attacks, including network bonds that can pay miners to support and protect a network regardless of the coin’s profitability, reducing the possibility of an attack.

Private Rights of Action, Enforcement and Other Legal Solutions

Like traditional cybercrime, attacks directed at virtual currencies and blockchains require both technical and legal solutions. From an enforcement perspective, those who attack the integrity of blockchains may be liable for a range of criminal and civil violations, including wire fraud and the unauthorized access into protected computer networks under the Computer Fraud and Abuse Act (CFAA). The CFAA also allows victims to bring private civil actions in federal court to obtain both compensatory damages and injunctive relief to prevent further attacks. Even in cases where the identity of those responsible for the attack is unknown, which is generally the case, plaintiffs can file “John Doe” complaints against unknown defendants. Plaintiffs can then use the power of the civil discovery process to issue subpoenas to third-party service providers, digital trading platforms, custodial wallet services and a range of other entities that will likely have valuable information that can be used to connect the crime to the perpetrator and assist in the recovery of stolen digital assets.

While there has been much emphasis placed upon the anonymity of Bitcoin and other virtual currencies, there are ways to peel back the layers to identify the internet protocol addresses, nodes and wallets used in an attack. Today more than ever, know-your-customer rules and other anti-money laundering regulations require trading platforms and other money service providers to verify the identities of those using their services. Further, services like Chainalysis, Elementus and Elliptic can be used to conduct blockchain network analysis to trace stolen digital assets to transfer, entry and exit points that can also lead to unmasking the identities of those involved.

Often complementing these private rights of action, the attackers may also become the subjects of fraud investigations by the Commodities Futures Trading Commission (CFTC) pursuant to violations of the anti-fraud provisions in the Commodity Exchange Act (CEA).[3] The CFTC may use its general anti-fraud and anti-manipulation authority to police public blockchain networks both to deter the risk of cyberattacks from affecting digital asset derivatives markets and for investor protection purposes. It is particularly likely to focus on cyberattacks that could affect the Bitcoin blockchain because several derivatives exchanges currently list bitcoin futures, options and swaps products, which could be affected by majority attacks. Moreover, the CFTC may begin to more closely monitor other blockchains as new derivatives products, such as ether futures, emerge and if the public pressures the agency to protect investors in digital asset markets more broadly.

Majority attacks are also market manipulations that have analogues in traditional commodity markets. For example, “spoofing” is the manipulative practice of entering orders into an exchange’s order book with the intention to cancel the orders before they are matched. In such a case, the trader uses a high-speed connection to an exchange to submit false information into the market and withdraw the information within milliseconds to defraud other traders. Similarly, the purpose of a majority attack is to use hashrate to submit false transaction data to the blockchain and defraud digital asset holders. Accordingly, the CFTC is not likely to shy away from these incidents due to the novelty of blockchain technology.

With a more nuanced understanding of blockchain immutability, market participants can make more informed business and legal decisions. This includes decisions about the design and use of various blockchains, the types of legal contracts to create (including digital contracts), and potentially how to assign and diversify risk in advance. For the myriad of companies whose services are now built on blockchains, this also includes not overstating security, making adequate disclosures and developing thorough terms of service. While there may be a need for new laws in certain areas, and clarity from regulators in many others, thoughtful participants can also act to protect themselves under our current legal frameworks.


[1] Cryptographic hash functions are mathematical operations run on digital data. By comparing the computed "hash" (the output from execution of the algorithm) to a known and expected hash value, a person can determine the data's integrity. A one-way hash can be generated from any piece of data, but the data cannot be generated from the hash.

[2] Mining on the Bitcoin blockchain is CPU intensive and relies on a proof-of-work mining algorithm based on SHA-256. By contrast, mining on the Ethereum blockchain is more GPU intensive and relies on a separate proof-of-work mining algorithm known as Ethash. 

[3] The commodity laws give the CFTC broad authority to prohibit and prosecute fraud, deception, price manipulation, etc. with respect to transactions in commodities, including in respect of spot transactions and, more specifically, transactions that involve virtual currencies. See Sections 6(c) and 9(a)(2) of the CEA and CFTC Regulations 180.1 and 180.2; see also CFTC v. Gelfman Blueprint, Inc. and Nicholas Gelfman, No. 1:17-cv-07181 (S.D.N.Y. Sept. 21, 2017); CFTC v. My Big Coin Pay, Inc., Randall Crater, and Mark Gillespie, No. 18-10077-RWZ (D. Mass, Jan 16, 2018); CFTC v. Patrick K. McDonnell, and CabbageTech Corp. d/b/a Coin Drop Markets, No. 18-cv-0361, (E.D.N.Y. Jan 18, 2018).

Michael Maloney of contributed to this article.

[View source.]

DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

© Perkins Coie | Attorney Advertising

Written by:

Perkins Coie

Perkins Coie on:

Readers' Choice 2017
Reporters on Deadline

"My best business intelligence, in one easy email…"

Your first step to building a free, personalized, morning email brief covering pertinent authors and topics on JD Supra:
*By using the service, you signify your acceptance of JD Supra's Privacy Policy.
Custom Email Digest
- hide

JD Supra Privacy Policy

Updated: May 25, 2018:

JD Supra is a legal publishing service that connects experts and their content with broader audiences of professionals, journalists and associations.

This Privacy Policy describes how JD Supra, LLC ("JD Supra" or "we," "us," or "our") collects, uses and shares personal data collected from visitors to our website (located at (our "Website") who view only publicly-available content as well as subscribers to our services (such as our email digests or author tools)(our "Services"). By using our Website and registering for one of our Services, you are agreeing to the terms of this Privacy Policy.

Please note that if you subscribe to one of our Services, you can make choices about how we collect, use and share your information through our Privacy Center under the "My Account" dashboard (available if you are logged into your JD Supra account).

Collection of Information

Registration Information. When you register with JD Supra for our Website and Services, either as an author or as a subscriber, you will be asked to provide identifying information to create your JD Supra account ("Registration Data"), such as your:

  • Email
  • First Name
  • Last Name
  • Company Name
  • Company Industry
  • Title
  • Country

Other Information: We also collect other information you may voluntarily provide. This may include content you provide for publication. We may also receive your communications with others through our Website and Services (such as contacting an author through our Website) or communications directly with us (such as through email, feedback or other forms or social media). If you are a subscribed user, we will also collect your user preferences, such as the types of articles you would like to read.

Information from third parties (such as, from your employer or LinkedIn): We may also receive information about you from third party sources. For example, your employer may provide your information to us, such as in connection with an article submitted by your employer for publication. If you choose to use LinkedIn to subscribe to our Website and Services, we also collect information related to your LinkedIn account and profile.

Your interactions with our Website and Services: As is true of most websites, we gather certain information automatically. This information includes IP addresses, browser type, Internet service provider (ISP), referring/exit pages, operating system, date/time stamp and clickstream data. We use this information to analyze trends, to administer the Website and our Services, to improve the content and performance of our Website and Services, and to track users' movements around the site. We may also link this automatically-collected data to personal information, for example, to inform authors about who has read their articles. Some of this data is collected through information sent by your web browser. We also use cookies and other tracking technologies to collect this information. To learn more about cookies and other tracking technologies that JD Supra may use on our Website and Services please see our "Cookies Guide" page.

How do we use this information?

We use the information and data we collect principally in order to provide our Website and Services. More specifically, we may use your personal information to:

  • Operate our Website and Services and publish content;
  • Distribute content to you in accordance with your preferences as well as to provide other notifications to you (for example, updates about our policies and terms);
  • Measure readership and usage of the Website and Services;
  • Communicate with you regarding your questions and requests;
  • Authenticate users and to provide for the safety and security of our Website and Services;
  • Conduct research and similar activities to improve our Website and Services; and
  • Comply with our legal and regulatory responsibilities and to enforce our rights.

How is your information shared?

  • Content and other public information (such as an author profile) is shared on our Website and Services, including via email digests and social media feeds, and is accessible to the general public.
  • If you choose to use our Website and Services to communicate directly with a company or individual, such communication may be shared accordingly.
  • Readership information is provided to publishing law firms and authors of content to give them insight into their readership and to help them to improve their content.
  • Our Website may offer you the opportunity to share information through our Website, such as through Facebook's "Like" or Twitter's "Tweet" button. We offer this functionality to help generate interest in our Website and content and to permit you to recommend content to your contacts. You should be aware that sharing through such functionality may result in information being collected by the applicable social media network and possibly being made publicly available (for example, through a search engine). Any such information collection would be subject to such third party social media network's privacy policy.
  • Your information may also be shared to parties who support our business, such as professional advisors as well as web-hosting providers, analytics providers and other information technology providers.
  • Any court, governmental authority, law enforcement agency or other third party where we believe disclosure is necessary to comply with a legal or regulatory obligation, or otherwise to protect our rights, the rights of any third party or individuals' personal safety, or to detect, prevent, or otherwise address fraud, security or safety issues.
  • To our affiliated entities and in connection with the sale, assignment or other transfer of our company or our business.

How We Protect Your Information

JD Supra takes reasonable and appropriate precautions to insure that user information is protected from loss, misuse and unauthorized access, disclosure, alteration and destruction. We restrict access to user information to those individuals who reasonably need access to perform their job functions, such as our third party email service, customer service personnel and technical staff. You should keep in mind that no Internet transmission is ever 100% secure or error-free. Where you use log-in credentials (usernames, passwords) on our Website, please remember that it is your responsibility to safeguard them. If you believe that your log-in credentials have been compromised, please contact us at

Children's Information

Our Website and Services are not directed at children under the age of 16 and we do not knowingly collect personal information from children under the age of 16 through our Website and/or Services. If you have reason to believe that a child under the age of 16 has provided personal information to us, please contact us, and we will endeavor to delete that information from our databases.

Links to Other Websites

Our Website and Services may contain links to other websites. The operators of such other websites may collect information about you, including through cookies or other technologies. If you are using our Website or Services and click a link to another site, you will leave our Website and this Policy will not apply to your use of and activity on those other sites. We encourage you to read the legal notices posted on those sites, including their privacy policies. We are not responsible for the data collection and use practices of such other sites. This Policy applies solely to the information collected in connection with your use of our Website and Services and does not apply to any practices conducted offline or in connection with any other websites.

Information for EU and Swiss Residents

JD Supra's principal place of business is in the United States. By subscribing to our website, you expressly consent to your information being processed in the United States.

  • Our Legal Basis for Processing: Generally, we rely on our legitimate interests in order to process your personal information. For example, we rely on this legal ground if we use your personal information to manage your Registration Data and administer our relationship with you; to deliver our Website and Services; understand and improve our Website and Services; report reader analytics to our authors; to personalize your experience on our Website and Services; and where necessary to protect or defend our or another's rights or property, or to detect, prevent, or otherwise address fraud, security, safety or privacy issues. Please see Article 6(1)(f) of the E.U. General Data Protection Regulation ("GDPR") In addition, there may be other situations where other grounds for processing may exist, such as where processing is a result of legal requirements (GDPR Article 6(1)(c)) or for reasons of public interest (GDPR Article 6(1)(e)). Please see the "Your Rights" section of this Privacy Policy immediately below for more information about how you may request that we limit or refrain from processing your personal information.
  • Your Rights
    • Right of Access/Portability: You can ask to review details about the information we hold about you and how that information has been used and disclosed. Note that we may request to verify your identification before fulfilling your request. You can also request that your personal information is provided to you in a commonly used electronic format so that you can share it with other organizations.
    • Right to Correct Information: You may ask that we make corrections to any information we hold, if you believe such correction to be necessary.
    • Right to Restrict Our Processing or Erasure of Information: You also have the right in certain circumstances to ask us to restrict processing of your personal information or to erase your personal information. Where you have consented to our use of your personal information, you can withdraw your consent at any time.

You can make a request to exercise any of these rights by emailing us at or by writing to us at:

Privacy Officer
JD Supra, LLC
10 Liberty Ship Way, Suite 300
Sausalito, California 94965

You can also manage your profile and subscriptions through our Privacy Center under the "My Account" dashboard.

We will make all practical efforts to respect your wishes. There may be times, however, where we are not able to fulfill your request, for example, if applicable law prohibits our compliance. Please note that JD Supra does not use "automatic decision making" or "profiling" as those terms are defined in the GDPR.

  • Timeframe for retaining your personal information: We will retain your personal information in a form that identifies you only for as long as it serves the purpose(s) for which it was initially collected as stated in this Privacy Policy, or subsequently authorized. We may continue processing your personal information for longer periods, but only for the time and to the extent such processing reasonably serves the purposes of archiving in the public interest, journalism, literature and art, scientific or historical research and statistical analysis, and subject to the protection of this Privacy Policy. For example, if you are an author, your personal information may continue to be published in connection with your article indefinitely. When we have no ongoing legitimate business need to process your personal information, we will either delete or anonymize it, or, if this is not possible (for example, because your personal information has been stored in backup archives), then we will securely store your personal information and isolate it from any further processing until deletion is possible.
  • Onward Transfer to Third Parties: As noted in the "How We Share Your Data" Section above, JD Supra may share your information with third parties. When JD Supra discloses your personal information to third parties, we have ensured that such third parties have either certified under the EU-U.S. or Swiss Privacy Shield Framework and will process all personal data received from EU member states/Switzerland in reliance on the applicable Privacy Shield Framework or that they have been subjected to strict contractual provisions in their contract with us to guarantee an adequate level of data protection for your data.

California Privacy Rights

Pursuant to Section 1798.83 of the California Civil Code, our customers who are California residents have the right to request certain information regarding our disclosure of personal information to third parties for their direct marketing purposes.

You can make a request for this information by emailing us at or by writing to us at:

Privacy Officer
JD Supra, LLC
10 Liberty Ship Way, Suite 300
Sausalito, California 94965

Some browsers have incorporated a Do Not Track (DNT) feature. These features, when turned on, send a signal that you prefer that the website you are visiting not collect and use data regarding your online searching and browsing activities. As there is not yet a common understanding on how to interpret the DNT signal, we currently do not respond to DNT signals on our site.

Access/Correct/Update/Delete Personal Information

For non-EU/Swiss residents, if you would like to know what personal information we have about you, you can send an e-mail to We will be in contact with you (by mail or otherwise) to verify your identity and provide you the information you request. We will respond within 30 days to your request for access to your personal information. In some cases, we may not be able to remove your personal information, in which case we will let you know if we are unable to do so and why. If you would like to correct or update your personal information, you can manage your profile and subscriptions through our Privacy Center under the "My Account" dashboard. If you would like to delete your account or remove your information from our Website and Services, send an e-mail to

Changes in Our Privacy Policy

We reserve the right to change this Privacy Policy at any time. Please refer to the date at the top of this page to determine when this Policy was last revised. Any changes to our Privacy Policy will become effective upon posting of the revised policy on the Website. By continuing to use our Website and Services following such changes, you will be deemed to have agreed to such changes.

Contacting JD Supra

If you have any questions about this Privacy Policy, the practices of this site, your dealings with our Website or Services, or if you would like to change any of the information you have provided to us, please contact us at:

JD Supra Cookie Guide

As with many websites, JD Supra's website (located at (our "Website") and our services (such as our email article digests)(our "Services") use a standard technology called a "cookie" and other similar technologies (such as, pixels and web beacons), which are small data files that are transferred to your computer when you use our Website and Services. These technologies automatically identify your browser whenever you interact with our Website and Services.

How We Use Cookies and Other Tracking Technologies

We use cookies and other tracking technologies to:

  1. Improve the user experience on our Website and Services;
  2. Store the authorization token that users receive when they login to the private areas of our Website. This token is specific to a user's login session and requires a valid username and password to obtain. It is required to access the user's profile information, subscriptions, and analytics;
  3. Track anonymous site usage; and
  4. Permit connectivity with social media networks to permit content sharing.

There are different types of cookies and other technologies used our Website, notably:

  • "Session cookies" - These cookies only last as long as your online session, and disappear from your computer or device when you close your browser (like Internet Explorer, Google Chrome or Safari).
  • "Persistent cookies" - These cookies stay on your computer or device after your browser has been closed and last for a time specified in the cookie. We use persistent cookies when we need to know who you are for more than one browsing session. For example, we use them to remember your preferences for the next time you visit.
  • "Web Beacons/Pixels" - Some of our web pages and emails may also contain small electronic images known as web beacons, clear GIFs or single-pixel GIFs. These images are placed on a web page or email and typically work in conjunction with cookies to collect data. We use these images to identify our users and user behavior, such as counting the number of users who have visited a web page or acted upon one of our email digests.

JD Supra Cookies. We place our own cookies on your computer to track certain information about you while you are using our Website and Services. For example, we place a session cookie on your computer each time you visit our Website. We use these cookies to allow you to log-in to your subscriber account. In addition, through these cookies we are able to collect information about how you use the Website, including what browser you may be using, your IP address, and the URL address you came from upon visiting our Website and the URL you next visit (even if those URLs are not on our Website). We also utilize email web beacons to monitor whether our emails are being delivered and read. We also use these tools to help deliver reader analytics to our authors to give them insight into their readership and help them to improve their content, so that it is most useful for our users.

Analytics/Performance Cookies. JD Supra also uses the following analytic tools to help us analyze the performance of our Website and Services as well as how visitors use our Website and Services:

  • HubSpot - For more information about HubSpot cookies, please visit
  • New Relic - For more information on New Relic cookies, please visit
  • Google Analytics - For more information on Google Analytics cookies, visit To opt-out of being tracked by Google Analytics across all websites visit This will allow you to download and install a Google Analytics cookie-free web browser.

Facebook, Twitter and other Social Network Cookies. Our content pages allow you to share content appearing on our Website and Services to your social media accounts through the "Like," "Tweet," or similar buttons displayed on such pages. To accomplish this Service, we embed code that such third party social networks provide and that we do not control. These buttons know that you are logged in to your social network account and therefore such social networks could also know that you are viewing the JD Supra Website.

Controlling and Deleting Cookies

If you would like to change how a browser uses cookies, including blocking or deleting cookies from the JD Supra Website and Services you can do so by changing the settings in your web browser. To control cookies, most browsers allow you to either accept or reject all cookies, only accept certain types of cookies, or prompt you every time a site wishes to save a cookie. It's also easy to delete cookies that are already saved on your device by a browser.

The processes for controlling and deleting cookies vary depending on which browser you use. To find out how to do so with a particular browser, you can use your browser's "Help" function or alternatively, you can visit which explains, step-by-step, how to control and delete cookies in most browsers.

Updates to This Policy

We may update this cookie policy and our Privacy Policy from time-to-time, particularly as technology changes. You can always check this page for the latest version. We may also notify you of changes to our privacy policy by email.

Contacting JD Supra

If you have any questions about how we use cookies and other tracking technologies, please contact us at:

- hide

This website uses cookies to improve user experience, track anonymous site usage, store authorization tokens and permit sharing on social media networks. By continuing to browse this website you accept the use of cookies. Click here to read more about how we use cookies.