D. Chaum, "Untraceable Electronic Mail Return Addresses, and Digital Pseudonyms", Communications of the ACM, 24, 2, Feb.1981, pp.84-88.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....In particular, routing protocols are intended to find alternate paths in the face of link failures. Perhaps the best solution is to use encryption and not worry about the problem. Properly encrypted traffic is immune to eavesdroppers and connection hijackers; a variety of anonymity schemes [26, 27] can be used to foil traffic analysis. On the other hand, it may be possible to use link cutting to enable monitoring attacks against anonymous communications networks [28] Similarly, link encryption can prevent an attacker from exploiting an attack. Encryption is not always feasible, so we ....

David L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, vol. 24, no. 2, pp. 84--90, 1981.

....the mobile must provide a symmetric key to be used by the Information Server to encrypt its reply so the proxy only has to pass on the opaque reply. However, this second case requires the server to implement an additional privacy enhancement. VI. MIXES AND PE LBS PROXIES David Chaum described in [12] a technique based on public key cryptography that allows an electronic mail system to hide who a participant communicates with as well as the content of the communication. More generally, messages are exchanged through a chain of one or more intermediaries called mixes . The purpose of a mix is ....

D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", Communications of the ACM (24)2, pp. 84-88, 1981.

....systems commonly rely on the existence of multiple, independent remote entities to mitigate the threat of hostile peers. Many systems [3, 4, 8, 10, 17, 18, 29, 34, 36] replicate computational or storage tasks among several remote sites to protect against integrity violations (data loss) Others [5, 6, 7, 16, 28]fragment tasks among several remote sites to protect against privacy violations (data leakage) In either case, exploiting the redundancy in the system requires the ability to determine whether two ostensibly different remote entities are actually different. Use of the plural pronoun is ....

D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", CACM 4 (2), 1982.

.... which is widely used in tactical military systems to prevent transmitters being located; temporary mobile subscriber identifiers, used in digital phones to provide users with some measure of location privacy; and anonymous remailers, which conceal the identity of the sender of an email message [3]. An important subdiscipline of information hiding is steganography. While cryptography is about protecting the content of messages, steganography is about concealing their very existence. It comes from Greek roots (######o #, #### ###) literally means covered writing [4] and is The authors ....

D. Chaum, "Untraceable electronic mail, return addresses and digital pseudonyms." Communications of the A.C.M., vol. 24, no. 2, pp. 84--88, Feb. 1981.

.... users 1; Delta Delta Delta ; N and outputs a permuted list of the plaintexts (m 1 ; Delta Delta Delta ; mN ) without revealing the relationship between (c 1 ; Delta Delta Delta ; c N ) and (m 1 ; Delta Delta Delta ; mN ) MIX nets have found many applications in anonymous communication [4], election schemes [4, 7, 13, 15] and payment systems [9] The original MIX net was proposed by Chaum [4] B.Pfitzmann and A.Pfitzmann, however, showed an attack by a sender, which is more complicated than a simple repeated ciphertext attack [14] Another problem of Chaum s MIX net, based on RSA, ....

.... Delta ; N and outputs a permuted list of the plaintexts (m 1 ; Delta Delta Delta ; mN ) without revealing the relationship between (c 1 ; Delta Delta Delta ; c N ) and (m 1 ; Delta Delta Delta ; mN ) MIX nets have found many applications in anonymous communication [4] election schemes [4, 7, 13, 15] and payment systems [9] The original MIX net was proposed by Chaum [4] B.Pfitzmann and A.Pfitzmann, however, showed an attack by a sender, which is more complicated than a simple repeated ciphertext attack [14] Another problem of Chaum s MIX net, based on RSA, is that the size of each ....

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, ACM 1981, pp. 84-88 "Undeniable Signatures,"

....of each MIX server is O(N ) Two new concepts are introduced, existential honesty and limited open verification. They will be useful for distributed computation in general. 1 Introduction 1. 1 Background In his extensive work to achieve anonymity, Chaum introduced the concept of a MIX net [6]. MIX nets have found many applications in anonymous communication [6] election schemes [6, 11, 19, 24] and payment systems [14] A MIX net takes from each user a ciphertext and outputs a permuted list of the plaintexts without revealing who has sent which plaintext, i.e. which plaintext ....

....and limited open verification. They will be useful for distributed computation in general. 1 Introduction 1. 1 Background In his extensive work to achieve anonymity, Chaum introduced the concept of a MIX net [6] MIX nets have found many applications in anonymous communication [6], election schemes [6, 11, 19, 24] and payment systems [14] A MIX net takes from each user a ciphertext and outputs a permuted list of the plaintexts without revealing who has sent which plaintext, i.e. which plaintext corresponds to which ciphertext. This aspect of a MIX net is also known as ....

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, ACM 1981, pp. 84-88 "Undeniable Signatures,"

....to use certain services. Several projects try to achieve unobservability and anonymity in open networks, including CROWDS (Reiter and Rubin, 1997) or ONION ROUTING (www.onion router.net) and anonymizer services such as www.anonymizer.com. These anonymity tools are often based on mix networks (Chaum, 1981). A mix network is a collection of routers the mixes that use layered public key encryption to conceal the path of a message through the network. Anonymization in the underlying communication network can be integrated in our framework but we will not describe this aspect in more detail in ....

Chaum, D. (1981): `Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms', Communications of the ACM, Vol. 24, No. 2, Feb. 1981, pp. 84 -- 88.

....user sends a request message containing its GUID key to some node where it is stored, and receives the data back. Let s now consider how to implement such a system in a way that ensures both privacy and e#ciency. Keeping Messages Private Privacy in Freenet is based on a variation of the mix net[5] scheme used in anonymous email networks. Freenet messages are not sent directly from sender to recipient, but travel through chains in which node A sends a message to node B, node B passes it on to node C, and so on, until the message finally reaches its recipient. Every message is also encrypted ....

D.L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms, " Communications of the ACM 24(2), 84-88 (1981).

....secret key. Then he recovers voters intentions and publishes all real ballots. 3. 1 Basic assumptions The underlying assumptions of this protocol are that: a) Every eligible voter can communicate with all administrators and the counter (b) There exists a securely untraceable e mail system [3, 6, 15]; c) There exists a secure blind threshold signature scheme [14] and a secure one way permutation function [24] d) The RSA signature scheme is secure [25] and ElGamal cryptosystem is secure [8] Several anonymous channel protocols [3, 6, 15, 21] have been proposed. The mixnet approach is used ....

.... (b) There exists a securely untraceable e mail system [3, 6, 15] c) There exists a secure blind threshold signature scheme [14] and a secure one way permutation function [24] d) The RSA signature scheme is secure [25] and ElGamal cryptosystem is secure [8] Several anonymous channel protocols [3, 6, 15, 21] have been proposed. The mixnet approach is used in [3, 21] to realize a sender untraceable e mail system. The basic assumption of the mix net approach is at least one mix agent is honest. In [23] Pfitzmann shows several attacks on the anonymous channels proposed in [21] The dc net method based ....

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D. Chaum. "Untraceable electronic mail, return addresses, and digital pseudonyms," Comm. of ACM, Vol. 24, No. 2, pp.84-88, 1981.

....suitable for large scale elections since the computation and communication overheads are small even if the number of voters is large. To achieve the fairness property, every voter encrypts his vote by a random secret key and sends this encrypted vote to the counter through an anonymous channel [11], 12] in the voting phase. In the opening phase, to recover voters intentions, every voter needs to send his random secret key 2 IEICE TRANS. FUNDAMENTALS, VOL. NO. to the counter through an anonymous channel. Any voter may not send his secret key to the counter and then the counter can not ....

....and publishes all real ballots. The underlying assumptions of this protocol are that: a) Every eligible voter can communicate with the administrator and he can not abstain from the election process after the registration phase; b) There exists a securely untraceable electronic e mail system [11], 12] c) There exists a secure uniquely blind signature scheme and secure one way permutation function [8] d) RSA cryptosystem is secure if factorization is intractable [18] e) ElGamal cryptosystem is secure if discrete logarithm problem is still intractable [19] f) At least (m Gamma ....

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D. Chaum. "Untraceable electronic mail, return addresses, and digital pseudonyms," Commun. of the ACM, Vol. 24, No. 2, pp.84-88, 1981.

....to prevent the monitoring attempt; hence, no anonymity for the users. In reality, such traffic analysis is not possible. In addition to that, under some reasonable assumptions such that some nodes of a network are trustable, it is possible to realize anonymous communication over a network, e.g. [Ch81, Ch88]. 6 2.4 Preliminaries of Cryptography In modern cryptology, the security of a cryptosystem can be based on computationally hard problems such as factoring a large number or solving a discrete logarithm in a group of large order. 2.4.1 Assumptions We assume that following two problems are ....

....authority to a user in one way communication. The proposed secure mailing list system makes use of this. Preventing leakage of e mail address The e mail address of a sender is not exhibited in a delivered message. However, members can communicate with each other individually. Using the idea of [Ch81], a public key is utilized as an anonymous return (e mail) address. Applying it to the proposed mailing list system, the mailing list program interprets a public key (computed from a certificate) as an address. Each message posted to the mailing list contains a certificate, which corresponds to ....

D. L. Chaum, "Untraceable electronic mail, return addresses and digital pseudonyms," Communications of the ACM, 24, 2, pp. 84--88, 1981.

....in doing so. Indeed, the knowledge programs set out in this paper are derived from the knowledge based programs of [11, 12] and those include temporal operators by default. The seminal work setting out properties, goals, and mechanisms for anonymity in communication is that of Chaum (cf. e.g. [6, 7]) Our work is the first we are aware to give an epistemic characterization of anonymity properties. However, anonymity properties have been formally defined in CSP [22] And, in [20] a formal notation was given for specifying anonymity protocols; however, that notation was not designed to specify ....

D. Chaum. "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms ", Communications of the ACM , v. 24, n. 2, Feb. 1981, pp. 84-88.

....Years According to INSPEC, January 1999 (Courtesy of J. L. Dugelay [5] being located; temporary mobile subscriber identifiers, used in digital phones to provide users with some measure of location privacy; and anonymous remailers, which conceal the identity of the sender of an e mail message [3]. An important subdiscipline of information hiding is steganography. While cryptography is about protecting the content of messages, steganography is about concealing their very existence. It comes from Greek roots literally means covered writing [151] and it is usually interpreted to mean ....

D. Chaum, "Untraceable electronic mail, return addresses and digital pseudonyms," Commun. ACM, vol. 24, no. 2, pp. 84--88, Feb. 1981.

....and for zero knowledge identification protocols, for instance. But a key distribution centre based on symmetric key cryptography must also protect the corresponding master secret key. Reference Model and Use Cases 78 4.5. 6 Mix Service The concept of a mix network was introduced by Chaum [Chaum 1981] as a primitive for privacy. A mix network can for instance be used to achieve anonymous communication over the Internet. A mix network consists of some number of mixservers, S 1 , S n say, each of which makes available a public key of a suitable encryption scheme. A user wanting to send a ....

D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", Communications of the ACM, 24 (2), pp.84-8, 1981.

....can be downloaded from http: freenet.sourceforge.net . It grew out of work originally done by the first author at the University of Edinburgh[11] 2 Related work Several strands of related work in this area can be distinguished. Anonymous point to point channels based on Chaum s mix net scheme[7] have been implemented for email by the Mixmaster remailer[19] and for general TCP IP traffic by onion routing[17] and Freedom[27] Such channels are not in themselves easily suited to one to many publication, however, and are best viewed as a complement to Freenet since they do not provide file ....

D.L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM 24(2), 84-88 (1981).

.... trust between the team members: Every member u i ; i 2 [1 : w] of the tiger team chooses the parameter k i and l 2 Z p Gamma1 values b ij 2 Z p Gamma1 which satisfy l X j=1 b ij = 0 (mod p Gamma 1) Then the values c ij : k i b ij (mod p Gamma 1) are sent through a secure MIX net [Chau81]. The outputs of the MIX net are added. We get o : w X i=1 l X j=1 c ij = l w X i=1 k i (mod p Gamma 1) 3 Now one member, e.g. Carol, recomputes her chosen kC with kCnew : kC Gamma w X i=1 k i = kC Gamma l Gamma1 o (mod p Gamma 1) and the condition is satisfied. Note ....

D.Chaum, "Untraceable electronic mail return addresses and digital pseudonyms", Communcations of the ACM, Vol. 24 (2), Feb., (1981), pp. 84 -- 88.

....be conform with data protection laws in several countries, as e.g. Germany. sensitive data requirements Transparent User Data Control Data State Information Derived Information Confidentiality (C) e t e encryption, access control p t p l b l encryption, temporary identities, MIXes [3] broadcast, dummy traffic and MIXes including switching [4] to protect called or calling party number) Integrity (I) e t e authentication, digital signatures p t p authentication, digital signatures controlled and verifiable routing, crossing exclusively trusted networks Availability ....

....of realizing a new service (MIX service) based on existing telecommunication infrastructure. We will focus mainly on signalling requirements that means requirements related to the exchange of security control data. Readers who are interested in how MIXes are realized in detail may want to read [3] or [4] Information about authentication protocols and realization aspects can be found in [6] and [9] The mechanisms shown in Tab. 1 serve the need for securing different types of data. The chosen examples illustrate the benefit of the proposed security interfaces and related protocol ....

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D. L. Chaum: "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", Communications of the ACM, Volume 24, No. 2, February 1981, pp. 84-88

....the benefits of anonymous and verifiable databases, particularly in the context of privacy against government bodies that wish to cross correlate data belonging to individuals in society. In [8] the true identity of each individual remains unknown and the individual employed a different pseudonym [9] when dealing with each government body or institution. The main feature of the work was that each individual must also have the ability to verify that his or her personal details held by an institution are correct. Further related work has also been reported in [10] However, one underlying ....

D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, vol. 24, no. 2, pp. 84--88, 1981.

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D. Chaum, "Untraceable Electronic Mail Return Addresses, and Digital Pseudonyms", Communications of the ACM, 24, 2, Feb.1981, pp.84-88.

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D. Chaum, "Untraceable Electronic Mail Return Addresses, and Digital Pseudonyms," Comm. ACM, vol. 24, no. 2, pp. 84-88, Feb. 1981.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, vol. 4, no. 2, pp. 84--88, February 1981.

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David Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", Communications of the ACM , v. 24, n. 2, Feb. 1981, pp. 84-88.

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Chaum, D. (1981), `Untraceable electronic mail, return addresses, and digital pseudonyms', Communications of the ACM 24(2), 84--88.

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D. Chaum. "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms," Communications of the ACM, Vol. 24, No. 2, Feb. 1981, pp. 84-- 88.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, vol. 24, no. 2, pp. 84--88, February 1981.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms, " Communications of the ACM, ACM 1981, pp. 84-88

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Comm. of the ACM, 1981, pp.84--88.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms, " Communications of the ACM, ACM 1981, pp. 84-88

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", Communications of the ACM, Vol. 24 No. 2, 1981, pp. 84-88.

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", Communications of the ACM, Vol. 24 No. 2, 1981, pp. 84-88.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Comm. of the ACM, 1981, pp.84--88.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM, ACM 1981, pp. 84-88.

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Chaum, D. (1981), `Untraceable electronic mail, return addresses, and digital pseudonyms', Communications of the ACM 24(2), 84--88.

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Chaum, D.: "Untraceable electronic mail, return addresses, and digital pseudonyms"; Communications of the ACM, 24, 2 (1981), 84-88.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms, " Communications of the ACM, ACM 1981, pp. 84-88

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David L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Commun. ACM, vol. 24, no. 2, pp. 84--90, 1981.

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David L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Commun. ACM, vol. 24, no. 2, pp. 84--90, 1981.

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D.L. Chaum, "Untraceable, electronic mail, return addresses, and digital pseudonyms", Com. of the ACM, Vol. 24, No.2, pp. 84-88, 1981.

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms", in Communications of the ACM, vol. 24 (2), 1981.

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D Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms", in Communications of the ACM vol 24 no 2 (Feb 1981) pp 84--88

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David L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Commun. ACM, vol. 24, no. 2, pp. 84--90, 1981.

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms," Communications of the ACM, vol. 24, no. 2, 1981.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms, " Communications of the ACM, ACM 1981, pp. 84-88

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D.L. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Communications of the ACM 24(2), 84-88 (1981).

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms," Comm. ACM, vol. 24, no. 2, 1981, pp. 84--88.

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms," Communications of the ACM 24(2), pp. 84--90, 1981.

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D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms, " Communications of the ACM, ACM 1981, pp. 84-88

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D. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms," Communications of the ACM 24(2), pp. 84-90, 1981.

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D.L. Chaum, "Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms," Comm. ACM, vol. 24, no. 2, 1981, pp. 84-90.

No context found.

D. Chaum, "Untraceable electronic mail, return addresses, and digital pseudonyms," Commu. of the ACM, 24(2) (1981) pp. 84-88.

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