10 results
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2. Distributed 'Magic Ink' Signatures
- Author
-
Markus Jakobsson and Moti Yung
- Subjects
Carbon copy ,business.product_category ,Computer science ,Magic (programming) ,Security token ,Computer security ,computer.software_genre ,Secret sharing ,Server ,Blind signature ,ComputingMilieux_COMPUTERSANDSOCIETY ,Carbon paper ,business ,computer ,Anonymity - Abstract
The physical analog of "blind signatures" of Chaum is a document and a carbon paper put into an envelope, allowing the signer to transfer his signature onto the document by signing on the envelope, and without opening it. Only the receiver can present the signed document while the signer cannot "unblind" its signature and get the document signed. When an authority signs "access tokens", "electronic coins", "credentials" or "passports", it makes sense to assume that whereas the users can typically enjoy the disassociation of the blindly signed token and the token itself (i.e. anonymity and privacy), there may be cases which require "unblinding" of a signature by the signing authority itself (to establish what is known as "audit trail" and to "revoke anonymity" in case of criminal activity). This leads us to consider a new notion of signature with the following physical parallel: The signer places a piece of paper with a carbon paper on top in an envelope as before (but the document on the paper is not yet written). The receiver then writes the document on the envelope using magic ink, e.g., ink that is only visible after being "developed". Due to the carbon copy, this results in the document being written in visible ink on the internal paper. Then, the signer signs the envelope (so its signature on the document is made available). The receiver gets the internal paper and the signer retains the envelope with the magic ink copy. Should the signer need to unblind the document, he can develop the magic ink and get the document copy on the envelope. Note that the signing is not blinded forever to the signer. We call this new type of signature a magic ink signature. We present an efficient method for distributively generating magic ink signatures, requiring a quorum of servers to produce a signature and a (possibly different) quorum to unblind a signature. The scheme is robust, and the unblinding is guaranteed to work even if a set of up to a threshold of signers refuses to cooperate, or actively cheats during either the signing or the unblinding protocol. We base our specific implementation on the DSS algorithm. Our construction demonstrates the extended power of distributed signing.
- Published
- 1997
3. NOTES FOR CONTRIBUTORS.
- Subjects
PERIODICALS ,SOCIAL sciences ,BIBLIOGRAPHY ,BRISTOL paper ,MONOGRAPHIC series ,CARBON copy - Abstract
The article presents instructions for contributors to the journal "Sociology." Contributions should be typed on quarto sheets, using double spacing, on one side of each page. Authors should submit the top copy and retain a carbon copy. The pages should be numbered serially. The title of the article, the author's name, and a biographical note on him should be typed on a flysheet which can readily be detached from the body of the article. A contributor should also supply an abstract of 100-200 words summarizing the article in such a way that the abstract can be read independently. Contributors are especially requested to ensure that all necessary details are provided in their references. Titles of journals and monograph series may be abbreviated according to the system used in International Bibliography of the Social Sciences. The notes should be typed on a separate page or pages from the text, as should the bibliography. Figures and maps should be drawn in opaque black ink on Bristol board, tracing film, or graph paper with faint blue ruling.
- Published
- 1967
4. Dry.
- Subjects
MICROENCAPSULATION ,CARBON paper ,COPYING ,CARBON copy - Abstract
The article reports on the development of encapsulation by the National Cash Register Co. to developed encapsulation in pursuit of another goal. The company was able to develop a copying paper that would eliminate the need for carbons as part of the program to promote clean and efficient business methods. The No Carbon Required paper is coated on its top surface with a light film of clay on its undersurface with a layer of extremely small cells containing oil.
- Published
- 1960
5. Was a carbon copy also typewritten?
- Author
-
Ordway Hilton
- Subjects
Carbon copy ,Materials science ,business.product_category ,Inkwell ,Ribbon ,Nanotechnology ,Carbon paper ,Composite material ,Line (text file) ,business ,Law ,Embossing ,Pathology and Forensic Medicine - Abstract
The writer considers how the ribbon copy of a typewritten document is affected by the preparation of a carbon copy. Factors of embossing, increase in line spacing, offsets on the back of the sheet and the presence of carbon paper ink mingled with the ribbon ink around points of paper fracture are evaluated. Dangers of misinterpretation of these factors are pointed out and proof that no carbon copy is discussed.
- Published
- 1983
6. Amoco's credit-card billing coup.
- Subjects
CARBON copy ,SALES ,CREDIT cards - Abstract
The article reports that Amoco Oil Co. is preparing to launch its Signature Verified Billing (SVB) program in the U.S. According to the author, SVB uses computers and image processing technology to simplify billing procedures by eliminating the practice of collecting data from carbon copies of individual sales slips. The company estimates that under the SVB system, the incoming paper load handled by the firm will be reduced by 90 percent. The Amoco system is expected to be adopted by banks to save money and time in processing credit card bills.
- Published
- 1979
7. Effect of Mono- and Poly-CH/P Exchange(s) on the Aromaticity of the Tropylium Ion.
- Author
-
Puri, Ankita and Gupta, Raakhi
- Subjects
AROMATICITY ,CARBON copy ,FUNCTIONAL groups ,PHOSPHORUS spectra ,POLYCYCLIC aromatic hydrocarbons ,NUCLEAR magnetic resonance - Abstract
In view of the fact that the phosphorus atom in its low co-ordination state (coordination numbers 1 and 2) has been termed as the carbon copy, there have been attempts to investigate, theoretically as well as experimentally, the effect of the exchange(s) of CH- moiety with phosphorus atom(s) (CH/P) on the structural and other aspects of the classical carbocyclic and heterocyclic systems. Tropylium ion is a well-known non-benzenoid aromatic system and has been studied extensively for its aromatic character. We have now investigated the effect of mono- and poly-CH/P exchange(s) on the aromaticity of the tropylium ion. For this purpose, the parameters based on the geometry and magnetic properties, namely bond equalization, aromatic stabilization energies (ASE), Nucleus-Independent Chemical Shift (NICS) values, (NICS(0), NICS(1), NICS(1)
zz ), proton nucleus magnetic resonance (1H-NMR) chemical shifts, magnetic susceptibility exaltation and magnetic anisotropic values of mono-, di-, tri- and tetra-phosphatropylium ions have been determined at the Density Functional Theory (DFT) (B3LYP/6-31+G(d)) level. Geometry optimization reveals bond length equalization. ASEs range from -46.3 kcal/mol to -6.2 kcal/mol in mono- and diphospha-analogues which are planar. However, the ions having three and four phosphorus atoms lose planarity and their ASE values approach the values typical for non-aromatic structures. Of the three NICS values, the NICS(1)zz is consistently negative showing aromatic character of all the systems studied. It is also supported by the magnetic susceptibility exaltations and magnetic anisotropic values. Furthermore, 1H-NMR chemical shifts also fall in the aromatic region. The conclusion that mono-, di-, tri- and tetra-phosphatropylium ions are aromatic in nature has been further corroborated by determining the energy gap between the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) (HOMO - LUMO gap), which falls in the range, ca. 3 × 10-19 -9 × 10-19 J. The systems having more than four phosphorus atoms are not able to sustain their monocyclic structure. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
8. Phosphorus as a carbon copy and as a photocopy: New conjugated materials featuring multiply bonded phosphorus.
- Author
-
Simpson, M. Cather and Protasiewicz, John D.
- Subjects
PHOSPHORUS ,CARBON copy ,PHOTOCOPYING ,PHOTOLUMINESCENCE ,STRUCTURAL engineering ,MULTIPLE bonds (Chemistry) - Abstract
Phosphaalkenes (RP=CR
2 ) and diphosphenes (RP=PR) are main group analogues of alkenes (R2 C=CR2 ). Molecules featuring such multiply bonded phosphorus functionalities often display structural features and chemical reactivities that mimic their purely organic counterparts, lending credence to the claim that these compounds are "carbon copies". We have been expanding this analogy to include oligomers and polymers with extended conjugation that directly involve P=C and P=P units. Many of these materials, however, display little or no photoluminescence (PL). This article summarizes our efforts to understand P=C and P=P photobehavior and to produce materials having significant PL that mimic or "photocopy" the PL properties of the phosphorus-free systems. Recent materials based on benz - oxaphospholes (BOPs), benzobisoxaphospholes (BBOPs), and higher analogues having significant fluorescence quantum yields are covered. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
9. The long-range interaction landscape of gene promoters.
- Author
-
Sanyal, Amartya, Lajoie, Bryan R., Jain, Gaurav, and Dekker, Job
- Subjects
PROMOTERS (Genetics) ,HUMAN genome ,CARBON copy ,GENE expression ,RNA ,COHESINS ,GENES - Abstract
The vast non-coding portion of the human genome is full of functional elements and disease-causing regulatory variants. The principles defining the relationships between these elements and distal target genes remain unknown. Promoters and distal elements can engage in looping interactions that have been implicated in gene regulation. Here we have applied chromosome conformation capture carbon copy (5C) to interrogate comprehensively interactions between transcription start sites (TSSs) and distal elements in 1% of the human genome representing the ENCODE pilot project regions. 5C maps were generated for GM12878, K562 and HeLa-S3 cells and results were integrated with data from the ENCODE consortium. In each cell line we discovered >1,000 long-range interactions between promoters and distal sites that include elements resembling enhancers, promoters and CTCF-bound sites. We observed significant correlations between gene expression, promoter-enhancer interactions and the presence of enhancer RNAs. Long-range interactions show marked asymmetry with a bias for interactions with elements located ?120 kilobases upstream of the TSS. Long-range interactions are often not blocked by sites bound by CTCF and cohesin, indicating that many of these sites do not demarcate physically insulated gene domains. Furthermore, only ?7% of looping interactions are with the nearest gene, indicating that genomic proximity is not a simple predictor for long-range interactions. Finally, promoters and distal elements are engaged in multiple long-range interactions to form complex networks. Our results start to place genes and regulatory elements in three-dimensional context, revealing their functional relationships. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
10. Wizards Brews New Fiction Line.
- Author
-
Milliot, Jim
- Subjects
PUBLISHING ,BOOKS & reading ,COPYING ,CARBON copy ,BOARD games - Abstract
The article reports that Wizards of the Coast has developed a successful book publishing program. The company sold more than 40 million copies since the company began publishing books more than 20 years ago to accompany its various role-playing and board games. Wizards has created a new line of independent fiction titles that it will begin publishing under the Wizards of the Coast Discoveries imprint starting in January 2007.
- Published
- 2007
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