Search results for "secret"

Hits ?▲	Authors	Title	Venue	Year	Link	Author keywords
118	K. Srinathan, N. Tharani Rajan, C. Pandu Rangan	Non-perfect Secret Sharing over General Access Structures.	INDOCRYPT	2002	DBLP DOI BibTeX RDF	non-threshold secret sharing, non-perfect secret sharing
91	László Csirmaz	The Size of a Share Must Be Large.	J. Cryptol.	1997	DBLP DOI BibTeX RDF	Polymatroid structures, Polymatroid structures, Secret sharing, Secret sharing, Key words, Ideal secret sharing schemes, Ideal secret sharing schemes, Perfect security, Perfect security
86	Giovanni Di Crescenzo	Sharing One Secret vs. Sharing Many Secrets: Tight Bounds for the Max Improvement Ratio.	MFCS	2001	DBLP DOI BibTeX RDF	Multi-Secret Sharing, Cryptography, Secret Sharing
86	Keith M. Martin, Josef Pieprzyk, Reihaneh Safavi-Naini, Huaxiong Wang	Changing Thresholds in the Absence of Secure Channels.	ACISP	1999	DBLP DOI BibTeX RDF	Threshold Changeable Secret Sharing, Shamir Secret Sharing, Geometrical Secret Sharing, Secret Sharing
83	Reihaneh Safavi-Naini, Huaxiong Wang	Secret sharing schemes with partial broadcast channels.	Des. Codes Cryptogr.	2006	DBLP DOI BibTeX RDF	94A17, 68P30, AMS classifications 94A62
78	Shaik Maleka, Amjed Shareef, C. Pandu Rangan	The deterministic protocol for rational secret sharing.	IPDPS	2008	DBLP DOI BibTeX RDF
78	Gustavus J. Simmons	Geometric Shared Secret and/or Shared Control Schemes.	CRYPTO	1990	DBLP DOI BibTeX RDF
77	Jaume Martí-Farré, Carles Padró	Ideal Secret Sharing Schemes Whose Minimal Qualified Subsets Have at Most Three Participants.	SCN	2006	DBLP DOI BibTeX RDF	Ideal access structures, Secret sharing representable matroids, Secret sharing, Ideal secret sharing schemes, Information rate
76	Phillip Rogaway, Mihir Bellare	Robust computational secret sharing and a unified account of classical secret-sharing goals.	CCS	2007	DBLP DOI BibTeX RDF	computational secret sharing, robust computational secret-sharing, provable security, cryptographic protocols, secret sharing, survivable storage
76	Jun Kurihara, Shinsaku Kiyomoto, Kazuhide Fukushima, Toshiaki Tanaka	A New (k, n)-Threshold Secret Sharing Scheme and Its Extension.	ISC	2008	DBLP DOI BibTeX RDF	threshold ramp scheme, entropy, random number, Secret sharing scheme, threshold scheme, ideal secret sharing scheme, exclusive-or
74	Li Bai	A Reliable (k, n) Image Secret Sharing Scheme.	DASC	2006	DBLP DOI BibTeX RDF	matrix projection, image processing, secret sharing
73	Lein Harn, Changlu Lin	Detection and identification of cheaters in ( t , n ) secret sharing scheme.	Des. Codes Cryptogr.	2009	DBLP DOI BibTeX RDF	Mathematics Subject Classification (2000) 94A62
72	Oriol Farràs, Jaume Martí-Farré, Carles Padró	Ideal Multipartite Secret Sharing Schemes.	EUROCRYPT	2007	DBLP DOI BibTeX RDF	Ideal access structures, Multipartite secret sharing, Multipartite matroids, Discrete polymatroids, Secret sharing, Ideal secret sharing schemes
68	Shlomi Dolev, Limor Lahiani, Moti Yung	Secret Swarm UnitReactive k-Secret Sharing.	INDOCRYPT	2007	DBLP DOI BibTeX RDF	mobile computing, secret sharing
67	Mihir Bellare, Lenore Cowen, Shafi Goldwasser	On the Structure of Secret Key Exchange Protocols.	CRYPTO	1989	DBLP DOI BibTeX RDF
67	László Csirmaz	The Size of a Share Must Be Large.	EUROCRYPT	1994	DBLP DOI BibTeX RDF	polymatroid structures, Secret sharing, ideal secret sharing schemes, perfect security
65	Ching-Nung Yang, Chung-Chun Wang, Tse-Shih Chen	Real Perfect Contrast Visual Secret Sharing Schemes with Reversing.	ACNS	2006	DBLP DOI BibTeX RDF	Visual secret sharing scheme, ideal contrast, secret sharing scheme
64	Lan Zhou, Willy Susilo, Yi Mu 0001	New Construction of Group Secret Handshakes Based on Pairings.	ICICS	2007	DBLP DOI BibTeX RDF	pairings, random oracle, Secret Handshake, Credential System
64	Lan Zhou, Willy Susilo, Yi Mu 0001	Three-Round Secret Handshakes Based on ElGamal and DSA.	ISPEC	2006	DBLP DOI BibTeX RDF	Oblivious Signature Based Envelope, Hidden Credential, Privacy, Key Exchange, DSA, ElGamal, Secret Handshake
63	Akitoshi Izumi, Yoshifumi Ueshige	A proposal of efficient scheme of key management using ID-based encryption and Biometrics.	MUE	2007	DBLP DOI BibTeX RDF
63	Chao-Wen Chan, Chin-Chen Chang 0001	Key Exchange Protocols for Multiparty Communication Services.	CW	2002	DBLP DOI BibTeX RDF
62	Yi-Chun Wang, Justie Su-tzu Juan	Simple Multi-Secret Sharing Schemes to Achieve the Optimal Maximum Improvement Ratio.	SUTC (2)	2006	DBLP DOI BibTeX RDF
62	Amos Beimel, Tamir Tassa, Enav Weinreb	Characterizing Ideal Weighted Threshold Secret Sharing.	TCC	2005	DBLP DOI BibTeX RDF
62	Renato M. Capocelli, Alfredo De Santis, Luisa Gargano, Ugo Vaccaro	On the Size of Shares for Secret Sharing Schemes.	CRYPTO	1991	DBLP DOI BibTeX RDF
62	Ernest F. Brickell	Some Ideal Secret Sharing Schemes.	EUROCRYPT	1989	DBLP DOI BibTeX RDF
61	Huaxiong Wang, Duncan S. Wong	On Secret Reconstruction in Secret Sharing Schemes.	IEEE Trans. Inf. Theory	2008	DBLP DOI BibTeX RDF
60	Josef Pieprzyk, Xian-Mo Zhang	Cheating Prevention in Secret Sharing over GF(pt).	INDOCRYPT	2001	DBLP DOI BibTeX RDF	Nonlinear Secret Sharing, Cheating Immunity, Secret Sharing
58	Shaik Maleka, Amjed Shareef, C. Pandu Rangan	Rational Secret Sharing with Repeated Games.	ISPEC	2008	DBLP DOI BibTeX RDF	distributed computing, game theory, Secret sharing, repeated games
58	Chin-Chen Chang 0001, Jun-Chou Chuang, Pei-Yu Lin	Sharing a Secret Two-Tone Image in Two Gray-Level Images.	ICPADS (2)	2005	DBLP DOI BibTeX RDF	data encryption, visual cryptography, image hiding, Visual secret sharing
58	Renato Renner, Stefan Wolf 0001	New Bounds in Secret-Key Agreement: The Gap between Formation and Secrecy Extraction.	EUROCRYPT	2003	DBLP DOI BibTeX RDF	reductions among primitives, information measures, quantum entanglement purification, Information-theoretic security, secret-key agreement
58	Chin-Chen Chang 0001, Tai-Xing Yu	Sharing a Secret Gray Image in Multiple Images.	CW	2002	DBLP DOI BibTeX RDF	secret sharing, Visual cryptography
58	Sergio Cabello, Carles Padró, Germán Sáez	Secret Sharing Schemes with Detection of Cheaters for a General Access Structure.	FCT	1999	DBLP DOI BibTeX RDF	Detection of cheaters, Robust and secure schemes, Cryptography, Secret sharing schemes
58	Taekyoung Kwon 0002, JooSeok Song	Security and efficiency in authentication protocols resistant to password guessing attack.	LCN	1997	DBLP DOI BibTeX RDF	password guessing attack resistance, secret, user-chosen weak secret, security-oriented protocols, cipher operations, protocol steps, poorly-chosen weak secret protection, security, efficiency, cryptographic protocols, key exchange, message authentication, authentication protocols, secure communications, random numbers, dictionary attacks
57	Hugo Krawczyk	Secret Sharing Made Short.	CRYPTO	1993	DBLP DOI BibTeX RDF
57	Benny Chor, Eyal Kushilevitz	Secret Sharing Over Infinite Domains (Extended Abstract).	CRYPTO	1989	DBLP DOI BibTeX RDF
56	Wenping Ma 0002, Fu Tai Zhang	New Methods to Construct Cheating Immune Multisecret Sharing Scheme.	CISC	2005	DBLP DOI BibTeX RDF	Quadratic Function, Cheating Immune Function, Multisecret Secret Sharing, Secret Sharing
56	Ching-Nung Yang, Tse-Shih Chen	An Image Secret Sharing Scheme with the Capability of Previvewing the Secret Image.	ICME	2007	DBLP DOI BibTeX RDF
55	Josef Pieprzyk, Xian-Mo Zhang	Cheating Prevention in Linear Secret Sharing.	ACISP	2002	DBLP DOI BibTeX RDF	Linear Secret Sharing Schemes, Cheating Identification, Cryptography, Secret Sharing, Cheating Detection
53	Vanesa Daza, Josep Domingo-Ferrer	On Partial Anonymity in Secret Sharing.	EuroPKI	2007	DBLP DOI BibTeX RDF	Privacy, Protocols, Secret sharing
53	Wieland Fischer, Jean-Pierre Seifert	Note on Fast Computation of Secret RSA Exponents.	ACISP	2002	DBLP DOI BibTeX RDF	Carmichael's $lambda$-function, Secret exponent, Short public key, RSA, Chinese Remainder Theorem, Key generation
53	Hossein Ghodosi, Josef Pieprzyk, Reihaneh Safavi-Naini	Secret Sharing in Multilevel and Compartmented Groups.	ACISP	1998	DBLP DOI BibTeX RDF	Hierarchical and Compartmented Access Structures, Ideal Schemes, Secret Sharing, Perfect Security
53	Carlo Blundo, Alfredo De Santis, Roberto de Simone, Ugo Vaccaro	Tight Bounds on the Information Rate of Secret Sharing Schemes.	Des. Codes Cryptogr.	1997	DBLP DOI BibTeX RDF	Information Rate and Cryptography, Entropy, Secret Sharing, Data Security
53	Woei-Jiunn Tsaur, Shi-Jinn Horng	Protocols for Designing a Fast and Perfect Group-Oriented Secret Key Sharing in Distributed Systems.	ISPAN	1996	DBLP DOI BibTeX RDF	Secret Key Sharing Scheme, Distributed Systems, Cryptography, Information Security, Group-Oriented Cryptography
53	Mansour Jamzad, Zahra Zahedi Kermani	Secure Steganography Using Gabor Filter and Neural Networks.	Trans. Data Hiding Multim. Secur.	2008	DBLP DOI BibTeX RDF	Texture similarity, Kohonen Neural Networks, Steganography, DCT, Image database, Gabor Filter
52	Tamir Tassa	Hierarchical Threshold Secret Sharing.	J. Cryptol.	2007	DBLP DOI BibTeX RDF
52	Wei Chen, Xiang Long, Yuebin Bai, Xiaopeng Gao	A New Dynamic Threshold Secret Sharing Scheme from Bilinear Maps.	ICPP Workshops	2007	DBLP DOI BibTeX RDF
52	Maged Hamada Ibrahim	Verifiable Threshold Sharing of a Large Secret Safe-Prime.	ITCC (1)	2005	DBLP DOI BibTeX RDF	Robust Threshold Signature Schemes, Multi-Prime RSA, RSA Function Sharing, Threshold Cryptography, VSS
52	Lein Harn, Hung-Yu Lin	An l-Span Generalized Secret Sharing Scheme.	CRYPTO	1992	DBLP DOI BibTeX RDF
52	Josh Cohen Benaloh, Jerry Leichter	Generalized Secret Sharing and Monotone Functions.	CRYPTO	1988	DBLP DOI BibTeX RDF
51	Brian King	Randomness Required for Linear Threshold Sharing Schemes Defined over Any Finite Abelian Group.	ACISP	2001	DBLP DOI BibTeX RDF	Linear secret sharing, Randomness requirements, Threshold secret sharing
50	Satoshi Obana, Toshinori Araki	Almost Optimum Secret Sharing Schemes Secure Against Cheating for Arbitrary Secret Distribution.	ASIACRYPT	2006	DBLP DOI BibTeX RDF
49	Shyong Jian Shyu, Chun-Chieh Chuang, Ying-Ru Chen, Ah-Fur Lai	Weighted Threshold Secret Image Sharing.	PSIVT	2009	DBLP DOI BibTeX RDF	Weighted shadow size, Chinese remainder theorem, Threshold secret sharing, Secret image sharing
49	Jaume Martí-Farré, Carles Padró	On Secret Sharing Schemes, Matroids and Polymatroids.	TCC	2007	DBLP DOI BibTeX RDF	Ideal access structures, Secret sharing, Matroids, Ideal secret sharing schemes, Information rate, Polymatroids
49	Hui-Xian Li, Liao-Jun Pang, Wan-Dong Cai	An Efficient Threshold Multi-group-Secret Sharing Scheme.	ICFIE	2007	DBLP DOI BibTeX RDF	Multi-group-secret sharing, Chinese Remain Theorem, Secret sharing, Threshold
49	Hiroki Koga, Etsuyo Ueda	Basic Properties of the (t, n)-Threshold Visual Secret Sharing Scheme with Perfect Reconstruction of Black Pixels.	Des. Codes Cryptogr.	2006	DBLP DOI BibTeX RDF	Secret sharing, Visual cryptography, Threshold scheme, Visual secret sharing
49	Brian King	Requirements for Group Independent Linear Threshold Secret Sharing Schemes.	ACISP	2002	DBLP DOI BibTeX RDF	linear secret sharing, group independent linear threshold schemes, monotone span programs and bounds on share size, secret sharing, threshold cryptography
49	Wen-Ai Jackson, Keith M. Martin, Christine M. O'Keefe	Mutually Trusted Authority-Free Secret Sharing Schemes.	J. Cryptol.	1997	DBLP DOI BibTeX RDF	Key words, Secret sharing schemes, Secret sharing schemes
49	Brian King	A Comment on Group Independent Threshold Sharing.	WISA	2003	DBLP DOI BibTeX RDF	integer span programs, group independent threshold schemes, black-box sharing, secret sharing, threshold cryptography, monotone span programs
48	Hong-Hao Chen, Cheng-Chi Lee, Chih-Chiang Lee, Hsien-Chu Wu, Chwei-Shyong Tsai	Multi-level visual secret sharing scheme with smooth-looking.	ICIS	2009	DBLP DOI BibTeX RDF	code book, non-pixel expansion shares, visual cryptography, visual secret sharing
48	Xiang-Wei Kong, Wen-Feng Liu, Xin-Gang You	Secret Message Location Steganalysis Based on Local Coherences of Hue.	PCM (2)	2005	DBLP DOI BibTeX RDF	locating secret message, the coherences of hue, steganography, steganalysis
48	Vinod Vaikuntanathan, Arvind Narayanan, K. Srinathan, C. Pandu Rangan, Kwangjo Kim	On the Power of Computational Secret Sharing.	INDOCRYPT	2003	DBLP DOI BibTeX RDF	computationally bounded players, monotone P, Secret sharing, access structures
48	Chaosheng Shu, Tsutomu Matsumoto, Hideki Imai	A Multi-Purpose Proof System - for Identity and Membership Proofs.	ASIACRYPT	1991	DBLP DOI BibTeX RDF
46	Caimei Wang, Zhengmao Li	Self-selecting Sub-secret Keys Sharing Scheme Based on Polynomials over Elliptic Curve.	IAS	2009	DBLP DOI BibTeX RDF
46	Hao Chen, San Ling, Chaoping Xing	Access Structures of Elliptic Secret Sharing Schemes.	IEEE Trans. Inf. Theory	2008	DBLP DOI BibTeX RDF
46	Nick S. Jones, Lluis Masanes	Key Distillation and the Secret-Bit Fraction.	IEEE Trans. Inf. Theory	2008	DBLP DOI BibTeX RDF
46	Amos Beimel, Noam Livne, Carles Padró	Matroids Can Be Far from Ideal Secret Sharing.	TCC	2008	DBLP DOI BibTeX RDF
46	Amos Beimel, Matthew K. Franklin	Weakly-Private Secret Sharing Schemes.	TCC	2007	DBLP DOI BibTeX RDF
46	Stanislaw Jarecki, Xiaomin Liu	Unlinkable Secret Handshakes and Key-Private Group Key Management Schemes.	ACNS	2007	DBLP DOI BibTeX RDF
46	Stanislaw Jarecki, Jihye Kim, Gene Tsudik	Authentication for Paranoids: Multi-party Secret Handshakes.	ACNS	2006	DBLP DOI BibTeX RDF
46	Gene Tsudik, Shouhuai Xu	A Flexible Framework for Secret Handshakes.	Privacy Enhancing Technologies	2006	DBLP DOI BibTeX RDF
46	Justie Su-tzu Juan, Chia-Li Huang	Efficient Secret Sharing Schemes from Room Square.	ICITA (2)	2005	DBLP DOI BibTeX RDF
46	Tamir Tassa	Hierarchical Threshold Secret Sharing.	TCC	2004	DBLP DOI BibTeX RDF
46	Miodrag J. Mihaljevic, Marc P. C. Fossorier, Hideki Imai	Secret-Public Storage Trade-Off for Broadcast Encryption Key Management.	ICICS	2004	DBLP DOI BibTeX RDF	system overheads trade-off, one-way mapping, key management, broadcast encryption, pseudorandom number generators, erasure channels
46	Yvo Desmedt, Kaoru Kurosawa, Tri Van Le	Error Correcting and Complexity Aspects of Linear Secret Sharing Schemes.	ISC	2003	DBLP DOI BibTeX RDF
46	Ronald Cramer, Serge Fehr	Optimal Black-Box Secret Sharing over Arbitrary Abelian Groups.	CRYPTO	2002	DBLP DOI BibTeX RDF
46	Chwei-Shyong Tsai, Chin-Chen Chang 0001	A Generalized Secret Image Sharing and Recovery Scheme.	IEEE Pacific Rim Conference on Multimedia	2001	DBLP DOI BibTeX RDF
46	Amir Herzberg, Stanislaw Jarecki, Hugo Krawczyk, Moti Yung	Proactive Secret Sharing Or: How to Cope With Perpetual Leakage.	CRYPTO	1995	DBLP DOI BibTeX RDF
46	Carlo Blundo, Alfredo De Santis, Luisa Gargano, Ugo Vaccaro	Secret Sharing Schemes with Veto Capabilities.	Algebraic Coding	1993	DBLP DOI BibTeX RDF
45	Stefan Droste	New Results on Visual Cryptography.	CRYPTO	1996	DBLP DOI BibTeX RDF	Secret Sharing Problem, Secret Sharing Scheme, Visual Cryptography
45	Josh Cohen Benaloh	Secret Sharing Homomorphisms: Keeping Shares of A Secret Sharing.	CRYPTO	1986	DBLP DOI BibTeX RDF
44	Alessandro Sorniotti, Refik Molva	Secret interest groups (SIGs) in social networks with an implementation on Facebook.	SAC	2010	DBLP DOI BibTeX RDF	secret interest groups, social networks, secret handshakes
44	Abedelaziz Mohaisen, YoungJae Maeng, Jeonil Kang, DaeHun Nyang, KyungHee Lee, Dowon Hong, Jong Wook Han	Protection Techniques of Secret Information in Non-tamper Proof Devices of Smart Home Network.	UIC	2008	DBLP DOI BibTeX RDF	secret information, code attestation, security and system integration, authentication, secret sharing, home network
44	Kamer Kaya, Ali Aydin Selçuk	A Verifiable Secret Sharing Scheme Based on the Chinese Remainder Theorem.	INDOCRYPT	2008	DBLP DOI BibTeX RDF	joint random secret sharing, Asmuth-Bloom secret sharing scheme, Chinese Remainder Theorem, Verifiability
44	Jovan Dj. Golic	On Matroid Characterization of Ideal Secret Sharing Schemes.	J. Cryptol.	1998	DBLP DOI BibTeX RDF	Matroids, Matroids, Key words, Ideal secret sharing schemes, Ideal secret sharing schemes, Access structures, Access structures
43	Tim Berners-Lee, Robert Cailliau, Ari Luotonen, Henrik Frystyk Nielsen, Arthur Secret	The World-Wide Web.	Linking the World's Information	2023	DBLP DOI BibTeX RDF
43	Lucas Secret, Eloïse Minder, Jean-Rémy Chardonnet	Conect - An application for hybrid conferences.	ISMAR Adjunct	2021	DBLP DOI BibTeX RDF
43	Ghislain Secret, Gil Utard	A Study of Reconstruction Process Load in P2P Storage Systems.	Globe	2008	DBLP DOI BibTeX RDF
43	Tim Berners-Lee, Robert Cailliau, Ari Luotonen, Henrik Frystyk Nielsen, Arthur Secret	The World-Wide Web.	Commun. ACM	1994	DBLP DOI BibTeX RDF
43	Huawang Qin, Yuewei Dai, Zhiquan Wang	A secret sharing scheme based on (t, n) threshold and adversary structure.	Int. J. Inf. Sec.	2009	DBLP DOI BibTeX RDF	Adversary structure, Cryptography, Information security, Secret sharing, Threshold
43	Ilker Nadi Bozkurt, Kamer Kaya, Ali Aydin Selçuk	Practical Threshold Signatures with Linear Secret Sharing Schemes.	AFRICACRYPT	2009	DBLP DOI BibTeX RDF	Linear secret sharing, function sharing, threshold cryptography
43	Yutaka Kawai, Shotaro Tanno, Takahiro Kondo, Kazuki Yoneyama, Noboru Kunihiro, Kazuo Ohta	Extension of Secret Handshake Protocols with Multiple Groups in Monotone Condition.	WISA	2008	DBLP DOI BibTeX RDF	Secret Handshake with Multiple Groups, Privacy preserving authentication, Monotone Condition, Anonymity
43	Shouhuai Xu, Moti Yung	K-Anonymous Multi-party Secret Handshakes.	Financial Cryptography	2007	DBLP DOI BibTeX RDF	privacy-preserving authentication, reusable credentials, multiple personality prevention, anonymity, unlinkability, secret handshake, credential systems
43	Christophe Tartary, Josef Pieprzyk, Huaxiong Wang	Verifiable Multi-secret Sharing Schemes for Multiple Threshold Access Structures.	Inscrypt	2007	DBLP DOI BibTeX RDF	Threshold Access Structures, Share Verifiability, Keyed One-Way Functions, Chinese Remainder Theorem, Secret Sharing Scheme
43	Shoulun Long, Josef Pieprzyk, Huaxiong Wang, Duncan S. Wong	Generalised Cumulative Arrays in Secret Sharing.	Des. Codes Cryptogr.	2006	DBLP DOI BibTeX RDF	Cumulative array, Perfect hash family, Secret sharing
43	Jong-Phil Yang, Kyung Hyune Rhee, Kouichi Sakurai	A Proactive Secret Sharing for Server Assisted Threshold Signatures.	HPCC	2006	DBLP DOI BibTeX RDF	Fault tolerant and Distributed Computing, Secret sharing
43	Gene Tsudik, Shouhuai Xu	Brief announcement: a flexible framework for secret handshakes.	PODC	2005	DBLP DOI BibTeX RDF	small secret handshakes, unobservability, anonymity, key management, privacy-preservation, credential systems
43	Shouhuai Xu, Moti Yung	k-anonymous secret handshakes with reusable credentials.	CCS	2004	DBLP DOI BibTeX RDF	privacy-preserving authentication, reusable credentials, anonymity, unlinkability, secret handshake, credential systems
43	Siaw-Lynn Ng	A Representation of a Family of Secret Sharing Matroids.	Des. Codes Cryptogr.	2003	DBLP DOI BibTeX RDF	projective geometry, matroids, ideal secret sharing schemes
43	Christian Cachin, Klaus Kursawe, Anna Lysyanskaya, Reto Strobl	Asynchronous verifiable secret sharing and proactive cryptosystems.	CCS	2002	DBLP DOI BibTeX RDF	model, secret sharing, asynchronous, proactive
43	Reina Yoshikawa, Shimin Guo, Kazuhiro Motegi, Yoshihide Igarashi	Secret Key Exchange Using Random Deals of Cards on Hierarchical Structures.	ISAAC	2000	DBLP DOI BibTeX RDF	hierarchical groups, key exchange graphs, secret bit transmission, information-theoretically secure, card games