53-462: (Redirected from ZEC ) Zec or ZEC may refer to: Zcash , a cryptocurrency Zec (surname) Philip Zec - a British political cartoonist who usually signed his work with only his surname Zone d'exploitation contrôlée , conservation areas in the Canadian province of Quebec Zimbabwe Electoral Commission Topics referred to by
106-469: A symmetric key , which is then used by symmetric-key cryptography to transmit data using the now-shared symmetric key for a symmetric key encryption algorithm. PGP , SSH , and the SSL/TLS family of schemes use this procedure; they are thus called hybrid cryptosystems . The initial asymmetric cryptography-based key exchange to share a server-generated symmetric key from the server to client has
159-639: A " brute-force key search attack ". However, such an attack is impractical if the amount of computation needed to succeed – termed the "work factor" by Claude Shannon – is out of reach of all potential attackers. In many cases, the work factor can be increased by simply choosing a longer key. But other algorithms may inherently have much lower work factors, making resistance to a brute-force attack (e.g., from longer keys) irrelevant. Some special and specific algorithms have been developed to aid in attacking some public key encryption algorithms; both RSA and ElGamal encryption have known attacks that are much faster than
212-411: A " man-in-the-middle attack " is possible, making any subordinate certificate wholly insecure. Most of the available public-key encryption software does not conceal metadata in the message header, which might include the identities of the sender and recipient, the sending date, subject field, and the software they use etc. Rather, only the body of the message is concealed and can only be decrypted with
265-607: A "t-addr", or they can be shielded and are controlled by a "z-addr". A shielded transaction uses a type of zero-knowledge proof , specifically a non-interactive zero-knowledge proof , called "zk-SNARK", which provides anonymity to the coin holders in the transaction. Zcash coins are either in a transparent pool or a shielded pool. As of December 2017 only around 4% of Zcash coins were in the shielded pool and at that time most cryptocurrency wallet programs did not support z-addrs and no web-based wallets supported them. The shielded pool of Zcash coins were further analyzed for security and it
318-629: A British cryptographer at the UK Government Communications Headquarters (GCHQ), conceived of the possibility of "non-secret encryption", (now called public key cryptography), but could see no way to implement it. In 1973, his colleague Clifford Cocks implemented what has become known as the RSA encryption algorithm , giving a practical method of "non-secret encryption", and in 1974 another GCHQ mathematician and cryptographer, Malcolm J. Williamson , developed what
371-661: A corresponding private key . Key pairs are generated with cryptographic algorithms based on mathematical problems termed one-way functions . Security of public-key cryptography depends on keeping the private key secret; the public key can be openly distributed without compromising security. There are many kinds of public-key cryptosystems, with different security goals, including digital signature , Diffie-Hellman key exchange , public-key key encapsulation , and public-key encryption . Public key algorithms are fundamental security primitives in modern cryptosystems , including applications and protocols that offer assurance of
424-407: A document or communication. Further applications built on this foundation include: digital cash , password-authenticated key agreement , time-stamping services and non-repudiation protocols. Because asymmetric key algorithms are nearly always much more computationally intensive than symmetric ones, it is common to use a public/private asymmetric key-exchange algorithm to encrypt and exchange
477-414: A key length, the chief security risk is that the private key of a pair becomes known. All security of messages, authentication, etc., will then be lost. Additionally, with the advent of quantum computing , many asymmetric key algorithms are considered vulnerable to attacks, and new quantum-resistant schemes are being developed to overcome the problem. All public key schemes are in theory susceptible to
530-691: A long list of "self-signed identity certificates" from PKI providers – these are used to check the bona fides of the certificate authority and then, in a second step, the certificates of potential communicators. An attacker who could subvert one of those certificate authorities into issuing a certificate for a bogus public key could then mount a "man-in-the-middle" attack as easily as if the certificate scheme were not used at all. An attacker who penetrates an authority's servers and obtains its store of certificates and keys (public and private) would be able to spoof, masquerade, decrypt, and forge transactions without limit, assuming that they were able to place themselves in
583-604: A major advantage over your opponent. Only at the end of the evolution from Berners-Lee designing an open internet architecture for CERN , its adaptation and adoption for the Arpanet ... did public key cryptography realise its full potential. — Ralph Benjamin These discoveries were not publicly acknowledged for 27 years, until the research was declassified by the British government in 1997. In 1976, an asymmetric key cryptosystem
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#1732793931060636-550: A man-in-the-middle attack relatively straightforward. Capturing the public key would only require searching for the key as it gets sent through the ISP's communications hardware; in properly implemented asymmetric key schemes, this is not a significant risk. In some advanced man-in-the-middle attacks, one side of the communication will see the original data while the other will receive a malicious variant. Asymmetric man-in-the-middle attacks can prevent users from realizing their connection
689-569: A piece. Ten percent of all coins mined for the first four years were to be allotted to the Zcash Company, its employees, the investors, and the non-profit Zcash Foundation. The setup of Zcash required the careful execution of a trusted setup procedure — something that subsequently became known as " The Ceremony " — to create the Zcash private key . In order to ensure privacy, a truly random enormous number needed to be generated to be used as
742-597: A prior shared secret. Merkle's "public key-agreement technique" became known as Merkle's Puzzles , and was invented in 1974 and only published in 1978. This makes asymmetric encryption a rather new field in cryptography although cryptography itself dates back more than 2,000 years. In 1977, a generalization of Cocks's scheme was independently invented by Ron Rivest , Adi Shamir and Leonard Adleman , all then at MIT . The latter authors published their work in 1978 in Martin Gardner 's Scientific American column, and
795-493: A public key encryption system is for encrypting communication to provide confidentiality – a message that a sender encrypts using the recipient's public key, which can be decrypted only by the recipient's paired private key. Another application in public key cryptography is the digital signature . Digital signature schemes can be used for sender authentication . Non-repudiation systems use digital signatures to ensure that one party cannot successfully dispute its authorship of
848-484: A purpose-built program running on a server computer – vouches for the identities assigned to specific private keys by producing a digital certificate. Public key digital certificates are typically valid for several years at a time, so the associated private keys must be held securely over that time. When a private key used for certificate creation higher in the PKI server hierarchy is compromised, or accidentally disclosed, then
901-486: A trusted courier. This key, which both parties must then keep absolutely secret, could then be used to exchange encrypted messages. A number of significant practical difficulties arise with this approach to distributing keys . In his 1874 book The Principles of Science , William Stanley Jevons wrote: Can the reader say what two numbers multiplied together will produce the number 8616460799 ? I think it unlikely that anyone but myself will ever know. Here he described
954-503: A type of zero-knowledge proof to provide anonymity in transactions. Zcash coins are either in a transparent pool or a shielded pool. Zcash offers private transactors the option of "selective disclosure", allowing a user to prove payment for auditing purposes. One such reason is to make it easier for private transactors to comply with anti-money laundering laws and tax regulations. Zcash transactions can be transparent, similar to bitcoin transactions, in which case they are controlled by
1007-485: A wired route inside the sender's own building. In summation, public keys are easier to alter when the communications hardware used by a sender is controlled by an attacker. One approach to prevent such attacks involves the use of a public key infrastructure (PKI); a set of roles, policies, and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. However, this has potential weaknesses. For example,
1060-413: Is compromised. This remains so even when one user's data is known to be compromised because the data appears fine to the other user. This can lead to confusing disagreements between users such as "it must be on your end!" when neither user is at fault. Hence, man-in-the-middle attacks are only fully preventable when the communications infrastructure is physically controlled by one or both parties; such as via
1113-399: Is different from Wikidata All article disambiguation pages All disambiguation pages Zcash Zcash is a privacy-focused cryptocurrency which is based on Bitcoin's codebase. It shares many similarities, such as a fixed total supply of 21 million units. Transactions can be transparent, similar to bitcoin transactions, or they can be shielded transactions which use
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#17327939310601166-401: Is genuine by verifying the signature using the public key. As long as the software publisher keeps the private key secret, even if a forger can distribute malicious updates to computers, they cannot convince the computers that any malicious updates are genuine. For example, a journalist can publish the public key of an encryption key pair on a web site so that sources can send secret messages to
1219-454: Is never trivial and very rapidly becomes unmanageable as the number of participants increases, or when secure channels are not available, or when, (as is sensible cryptographic practice), keys are frequently changed. In particular, if messages are meant to be secure from other users, a separate key is required for each possible pair of users. By contrast, in a public-key cryptosystem, the public keys can be disseminated widely and openly, and only
1272-462: Is now known as Diffie–Hellman key exchange . The scheme was also passed to the US's National Security Agency . Both organisations had a military focus and only limited computing power was available in any case; the potential of public key cryptography remained unrealised by either organization: I judged it most important for military use ... if you can share your key rapidly and electronically, you have
1325-750: The Bootstrap Project (Bootstrap) in a company blog post titled "ECC’s owners to donate ECC". A majority of the investors and owners of Zerocoin Electric Coin Company LLC (ECC) have agreed to donate the ECC company as the wholly owned property of Bootstrap. ECC's blog post claims that nothing will change within the company other than the ownership including the Board of Directors. On October 27, 2020, ECC announced that its shareholders have officially voted in favor of donating 100 percent of
1378-421: The PKI system (software, hardware, and management) is trust-able by all involved. A " web of trust " decentralizes authentication by using individual endorsements of links between a user and the public key belonging to that user. PGP uses this approach, in addition to lookup in the domain name system (DNS). The DKIM system for digitally signing emails also uses this approach. The most obvious application of
1431-517: The advantage of not requiring that a symmetric key be pre-shared manually, such as on printed paper or discs transported by a courier, while providing the higher data throughput of symmetric key cryptography over asymmetric key cryptography for the remainder of the shared connection. As with all security-related systems, there are various potential weaknesses in public-key cryptography. Aside from poor choice of an asymmetric key algorithm (there are few that are widely regarded as satisfactory) or too short
1484-411: The algorithm came to be known as RSA , from their initials. RSA uses exponentiation modulo a product of two very large primes , to encrypt and decrypt, performing both public key encryption and public key digital signatures. Its security is connected to the extreme difficulty of factoring large integers , a problem for which there is no known efficient general technique. A description of the algorithm
1537-413: The attacker using the correct public keys for the different communication segments so as to avoid suspicion. A communication is said to be insecure where data is transmitted in a manner that allows for interception (also called " sniffing "). These terms refer to reading the sender's private data in its entirety. A communication is particularly unsafe when interceptions can not be prevented or monitored by
1590-434: The available metadata to a third party. The concept is based around an open repository containing separately encrypted metadata blocks and encrypted messages. Only the intended recipient is able to decrypt the metadata block, and having done so they can identify and download their messages and decrypt them. Such a messaging system is at present in an experimental phase and not yet deployed. Scaling this method would reveal to
1643-447: The brute-force approach. None of these are sufficiently improved to be actually practical, however. Major weaknesses have been found for several formerly promising asymmetric key algorithms. The "knapsack packing" algorithm was found to be insecure after the development of a new attack. As with all cryptographic functions, public-key implementations may be vulnerable to side-channel attacks that exploit information leakage to simplify
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1696-441: The certificate authority issuing the certificate must be trusted by all participating parties to have properly checked the identity of the key-holder, to have ensured the correctness of the public key when it issues a certificate, to be secure from computer piracy, and to have made arrangements with all participants to check all their certificates before protected communications can begin. Web browsers , for instance, are supplied with
1749-495: The communication stream. Despite its theoretical and potential problems, Public key infrastructure is widely used. Examples include TLS and its predecessor SSL , which are commonly used to provide security for web browser transactions (for example, most websites utilize TLS for HTTPS ). Aside from the resistance to attack of a particular key pair, the security of the certification hierarchy must be considered when deploying public key systems. Some certificate authority – usually
1802-429: The company's shares to Bootstrap. On March 30, 2021, the company's transparency report said that it is "now a wholly owned entity of the 501(c)3 Bootstrap". In September 2023, a mining pool named ViaBTC had seized control of over half the hashing power on Zcash. This 51% dominance raised worries about an attack a 51% attack where they could potentially manipulate transactions and harm the network. To shield users from
1855-415: The confidentiality and authenticity of electronic communications and data storage. They underpin numerous Internet standards, such as Transport Layer Security (TLS) , SSH , S/MIME , and PGP . Compared to symmetric cryptography , public-key cryptography can be too slow for many purposes, so these protocols often combine symmetric cryptography with public-key cryptography in hybrid cryptosystems . Before
1908-436: The corresponding private keys need be kept secret. The two best-known types of public key cryptography are digital signature and public-key encryption : For example, a software publisher can create a signature key pair and include the public key in software installed on computers. Later, the publisher can distribute an update to the software signed using the private key, and any computer receiving an update can confirm it
1961-602: The event. The private key was generated, and used to instantiate Zcash, and the computers used in the process were reportedly destroyed. In 2022, Edward Snowden claimed to have participated in The Ceremony under a pseudonym. On February 21, 2019, the "Zcash Company" announced a re-branding as the Electric Coin Company (ECC). On May 19, 2020, a paper titled "Alt-Coin Traceability" investigated
2014-414: The mid-1970s, all cipher systems used symmetric key algorithms , in which the same cryptographic key is used with the underlying algorithm by both the sender and the recipient, who must both keep it secret. Of necessity, the key in every such system had to be exchanged between the communicating parties in some secure way prior to any use of the system – for instance, via a secure channel . This requirement
2067-461: The news organization in ciphertext. Only the journalist who knows the corresponding private key can decrypt the ciphertexts to obtain the sources' messages—an eavesdropper reading email on its way to the journalist cannot decrypt the ciphertexts. However, public-key encryption does not conceal metadata like what computer a source used to send a message, when they sent it, or how long it is. Public-key encryption on its own also does not tell
2120-410: The potential fallout, Coinbase swiftly enacted a series of defensive measures, including placing Zcash markets into "limit-only" mode, effectively quelling significant price swings while the situation unfolded. Private key Public-key cryptography , or asymmetric cryptography , is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and
2173-643: The privacy of Zcash and another cryptocurrency Monero . This paper concluded that "more academic research is needed in Zcash overall" and that the privacy guarantees of Zcash are "questionable". The paper claimed that, since the current heuristics from a 2018 Usenix Security Symposium paper entitled "An Empirical Analysis of Anonymity in Zcash" still continue today, the result is making Zcash less anonymous and more traceable. On June 8, 2020, Chainalysis added support for Zcash to their Chainalysis Reactor and "Know Your Transaction" (KYT) products. They noted that less than 1% of ZEC transactions were completely shielded, with
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2226-411: The private key of the intended recipient. This means that a third party could construct quite a detailed model of participants in a communication network, along with the subjects being discussed, even if the message body itself is hidden. However, there has been a recent demonstration of messaging with encrypted headers, which obscures the identities of the sender and recipient, and significantly reduces
2279-421: The private key, while also ensuring that no person or computer retains a copy of the key, or could subsequently regenerate the key. If the private key were available, counterfeit Zcash coins could be generated. The Ceremony was a two-day process, executed simultaneously during a short window of time in six different locations globally, by persons who did not know in advance who else was going to be participating in
2332-576: The recipient anything about who sent a message —it just conceals the content of the message. One important issue is confidence/proof that a particular public key is authentic, i.e. that it is correct and belongs to the person or entity claimed, and has not been tampered with or replaced by some (perhaps malicious) third party. There are several possible approaches, including: A public key infrastructure (PKI), in which one or more third parties – known as certificate authorities – certify ownership of key pairs. TLS relies upon this. This implies that
2385-467: The relationship of one-way functions to cryptography, and went on to discuss specifically the factorization problem used to create a trapdoor function . In July 1996, mathematician Solomon W. Golomb said: "Jevons anticipated a key feature of the RSA Algorithm for public key cryptography, although he certainly did not invent the concept of public key cryptography." In 1970, James H. Ellis ,
2438-403: The same term [REDACTED] This disambiguation page lists articles associated with the title Zec . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Zec&oldid=1026887637 " Category : Disambiguation pages Hidden categories: Short description
2491-547: The search for a secret key. These are often independent of the algorithm being used. Research is underway to both discover, and to protect against, new attacks. Another potential security vulnerability in using asymmetric keys is the possibility of a "man-in-the-middle" attack , in which the communication of public keys is intercepted by a third party (the "man in the middle") and then modified to provide different public keys instead. Encrypted messages and responses must, in all instances, be intercepted, decrypted, and re-encrypted by
2544-557: The sender, receiver and amount all hidden, enabling Chainalysis to provide partial information for over 99% of ZEC activity. Chainalysis also cites a research report by the RAND corporation which revealed that less than 0.2% of the cryptocurrency addresses mentioned on the dark web were Zcash or Dash addresses. On October 12, 2020, the Electronic Coin Company announced a new non-profit 501(c)3 organization called
2597-514: The sender. A man-in-the-middle attack can be difficult to implement due to the complexities of modern security protocols. However, the task becomes simpler when a sender is using insecure media such as public networks, the Internet , or wireless communication. In these cases an attacker can compromise the communications infrastructure rather than the data itself. A hypothetical malicious staff member at an Internet service provider (ISP) might find
2650-407: The third party only the inbox server being used by the recipient and the timestamp of sending and receiving. The server could be shared by thousands of users, making social network modelling much more challenging. During the early history of cryptography , two parties would rely upon a key that they would exchange by means of a secure, but non-cryptographic, method such as a face-to-face meeting, or
2703-420: Was completed by the for-profit Zcash Company, led by Zooko Wilcox , a Colorado -based computer security specialist and cypherpunk . In October 2016, The Zcash Company raised over $ 3 million from Silicon Valley venture capitalists to complete the development of Zcash. Zcash was first mined in late October 2016. The initial demand was high, and within a week Zcash coins were trading for five thousand dollars
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#17327939310602756-492: Was found that the anonymity set can be shrunk considerably by heuristics-based identifiable patterns of usage. While miners receive 80% of a block reward , 20% is given to the "Zcash development fund": 8% to Zcash Open Major Grants, 7% to Electric Coin Co., and 5% to The Zcash Foundation. Development work on Zcash began in 2013 by Johns Hopkins University professor Matthew Green and some of his graduate students. The development
2809-517: Was published by Whitfield Diffie and Martin Hellman who, influenced by Ralph Merkle 's work on public key distribution, disclosed a method of public key agreement. This method of key exchange, which uses exponentiation in a finite field , came to be known as Diffie–Hellman key exchange . This was the first published practical method for establishing a shared secret-key over an authenticated (but not confidential) communications channel without using
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