Probabilistic encryption

About: Probabilistic encryption is a research topic. Over the lifetime, 6419 publications have been published within this topic receiving 208978 citations.

A fully homomorphic encryption scheme

Abstract: We propose the first fully homomorphic encryption scheme, solving an old open problem. Such a scheme allows one to compute arbitrary functions over encrypted data without the decryption key—i.e., given encryptions E(m1), ..., E( mt) of m1, ..., m t, one can efficiently compute a compact ciphertext that encrypts f(m1, ..., m t) for any efficiently computable function f. Fully homomorphic encryption has numerous applications. For example, it enables encrypted search engine queries—i.e., a search engine can give you a succinct encrypted answer to your (boolean) query without even knowing what your query was. It also enables searching on encrypted data; you can store your encrypted data on a remote server, and later have the server retrieve only files that (when decrypted) satisfy some boolean constraint, even though the server cannot decrypt the files on its own. More broadly, it improves the efficiency of secure multiparty computation. In our solution, we begin by designing a somewhat homomorphic "boostrappable" encryption scheme that works when the function f is the scheme's own decryption function. We then show how, through recursive self-embedding, bootstrappable encryption gives fully homomorphic encryption.

Introduction to Modern Cryptography

Abstract: Preface I. Introduction and Classical Cryptography Introduction Cryptography and Modern Cryptography The Setting of Private-Key Encryption Historical Ciphers and Their Cryptanalysis Principles of Modern Cryptography Principle 1 - Formal Definitions Principle 2 - Precise Assumptions Principle 3 - Proofs of Security Provable Security and Real-World Security References and Additional Reading Exercises Perfectly Secret Encryption Definitions The One-Time Pad Limitations of Perfect Secrecy Shannon's Theorem References and Additional Reading Exercises II. Private-Key (Symmetric) Cryptography Private-Key Encryption Computational Security The Concrete Approach The Asymptotic Approach Defining Computationally Secure Encryption The Basic Definition of Security Semantic Security Constructing Secure Encryption Schemes Pseudorandom Generators and Stream Ciphers Proofs by Reduction A Secure Fixed-Length Encryption Scheme Stronger Security Notions Security for Multiple Encryptions Chosen-Plaintext Attacks and CPA-Security Constructing CPA-Secure Encryption Schemes Pseudorandom Functions and Block Ciphers CPA-Secure Encryption from Pseudorandom Functions Modes of Operation Stream-Cipher Modes of Operation Block-Cipher Modes of Operation Chosen-Ciphertext Attacks Defining CCA-Security Padding-Oracle Attacks References and Additional Reading Exercises Message Authentication Codes Message Integrity Secrecy vs. Integrity Encryption vs. Message Authentication Message Authentication Codes - Definitions Constructing Secure Message Authentication Codes A Fixed-Length MAC Domain Extension for MACs CBC-MAC The Basic Construction Proof of Security Authenticated Encryption Definitions Generic Constructions Secure Communication Sessions CCA-Secure Encryption Information-Theoretic MACs Constructing Information-Theoretic MACs Limitations on Information-Theoretic MACs References and Additional Reading Exercises Hash Functions and Applications Definitions Collision Resistance Weaker Notions of Security Domain Extension: The Merkle-Damgard Transform Message Authentication Using Hash Functions Hash-and-MAC HMAC Generic Attacks on Hash Functions Birthday Attacks for Finding Collisions Small-Space Birthday Attacks Time/Space Tradeoffs for Inverting Functions The Random-Oracle Model The Random-Oracle Model in Detail Is the Random-Oracle Methodology Sound? Additional Applications of Hash Functions Fingerprinting and Deduplication Merkle Trees Password Hashing Key Derivation Commitment Schemes References and Additional Reading Exercises Practical Constructions of Symmetric-Key Primitives Stream Ciphers Linear-Feedback Shift Registers Adding Nonlinearity Trivium RC4 Block Ciphers Substitution-Permutation Networks Feistel Networks DES - The Data Encryption Standard 3DES: Increasing the Key Length of a Block Cipher AES - The Advanced Encryption Standard Differential and Linear Cryptanalysis Hash Functions Hash Functions from Block Ciphers MD5 SHA-0, SHA-1, and SHA-2 SHA-3 (Keccak) References and Additional Reading Exercises Theoretical Constructions of Symmetric-Key Primitives One-Way Functions Definitions Candidate One-Way Functions Hard-Core Predicates From One-Way Functions to Pseudorandomness Hard-Core Predicates from One-Way Functions A Simple Case A More Involved Case The Full Proof Constructing Pseudorandom Generators Pseudorandom Generators with Minimal Expansion Increasing the Expansion Factor Constructing Pseudorandom Functions Constructing (Strong) Pseudorandom Permutations Assumptions for Private-Key Cryptography Computational Indistinguishability References and Additional Reading Exercises III. Public-Key (Asymmetric) Cryptography Number Theory and Cryptographic Hardness Assumptions Preliminaries and Basic Group Theory Primes and Divisibility Modular Arithmetic Groups The Group ZN Isomorphisms and the Chinese Remainder Theorem Primes, Factoring, and RSA Generating Random Primes Primality Testing The Factoring Assumption The RSA Assumption Relating the RSA and Factoring Assumptions Cryptographic Assumptions in Cyclic Groups Cyclic Groups and Generators The Discrete-Logarithm/Diffie-Hellman Assumptions Working in (Subgroups of) Zp Elliptic Curves Cryptographic Applications One-Way Functions and Permutations Constructing Collision-Resistant Hash Functions References and Additional Reading Exercises Algorithms for Factoring and Computing Discrete Logarithms Algorithms for Factoring Pollard's p - 1 Algorithm Pollard's Rho Algorithm The Quadratic Sieve Algorithm Algorithms for Computing Discrete Logarithms The Pohlig-Hellman Algorithm The Baby-Step/Giant-Step Algorithm Discrete Logarithms from Collisions The Index Calculus Algorithm Recommended Key Lengths References and Additional Reading Exercises Key Management and the Public-Key Revolution Key Distribution and Key Management A Partial Solution: Key-Distribution Centers Key Exchange and the Diffie-Hellman Protocol The Public-Key Revolution References and Additional Reading Exercises Public-Key Encryption Public-Key Encryption - An Overview Definitions Security against Chosen-Plaintext Attacks Multiple Encryptions Security against Chosen-Ciphertext Attacks Hybrid Encryption and the KEM/DEM Paradigm CPA-Security CCA-Security CDH/DDH-Based Encryption El Gamal Encryption DDH-Based Key Encapsulation A CDH-Based KEM in the Random-Oracle Model Chosen-Ciphertext Security and DHIES/ECIES RSA Encryption Plain RSA Padded RSA and PKCS #1 v1.5 CPA-Secure Encryption without Random Oracles OAEP and RSA PKCS #1 v A CCA-Secure KEM in the Random-Oracle Model RSA Implementation Issues and Pitfalls References and Additional Reading Exercises Digital Signature Schemes Digital Signatures - An Overview Definitions The Hash-and-Sign Paradigm RSA Signatures Plain RSA RSA-FDH and PKCS #1 v Signatures from the Discrete-Logarithm Problem The Schnorr Signature Scheme DSA and ECDSA Signatures from Hash Functions Lamport's Signature Scheme Chain-Based Signatures Tree-Based Signatures Certificates and Public-Key Infrastructures Putting It All Together - SSL/TLS Signcryption References and Additional Reading Exercises Advanced Topics in Public-Key Encryption Public-Key Encryption from Trapdoor Permutations Trapdoor Permutations Public-Key Encryption from Trapdoor Permutations The Paillier Encryption Scheme The Structure of ZN2 The Paillier Encryption Scheme Homomorphic Encryption Secret Sharing and Threshold Encryption Secret Sharing Verifiable Secret Sharing Threshold Encryption and Electronic Voting The Goldwasser-Micali Encryption Scheme Quadratic Residues Modulo a Prime Quadratic Residues Modulo a Composite The Quadratic Residuosity Assumption The Goldwasser-Micali Encryption Scheme The Rabin Encryption Scheme Computing Modular Square Roots A Trapdoor Permutation Based on Factoring The Rabin Encryption Scheme References and Additional Reading Exercises Index of Common Notation Appendix A: Mathematical Background Identities and Inequalities Asymptotic Notation Basic Probability The "Birthday" Problem Finite Fields Appendix B: Basic Algorithmic Number Theory Integer Arithmetic Basic Operations The Euclidean and Extended Euclidean Algorithms Modular Arithmetic Basic Operations Computing Modular Inverses Modular Exponentiation Montgomery Multiplication Choosing a Uniform Group Element Finding a Generator of a Cyclic Group Group-Theoretic Background Efficient Algorithms References and Additional Reading Exercises References Index

A symmetric image encryption scheme based on 3D chaotic cat maps

Abstract: Encryption of images is different from that of texts due to some intrinsic features of images such as bulk data capacity and high redundancy, which are generally difficult to handle by traditional methods. Due to the exceptionally desirable properties of mixing and sensitivity to initial conditions and parameters of chaotic maps, chaos-based encryption has suggested a new and efficient way to deal with the intractable problem of fast and highly secure image encryption. In this paper, the two-dimensional chaotic cat map is generalized to 3D for designing a real-time secure symmetric encryption scheme. This new scheme employs the 3D cat map to shuffle the positions (and, if desired, grey values as well) of image pixels and uses another chaotic map to confuse the relationship between the cipher-image and the plain-image, thereby significantly increasing the resistance to statistical and differential attacks. Thorough experimental tests are carried out with detailed analysis, demonstrating the high security and fast encryption speed of the new scheme.

Evaluating 2-DNF formulas on ciphertexts

Abstract: Let ψ be a 2-DNF formula on boolean variables x1,...,xn ∈ {0,1}. We present a homomorphic public key encryption scheme that allows the public evaluation of ψ given an encryption of the variables x1,...,xn. In other words, given the encryption of the bits x1,...,xn, anyone can create the encryption of ψ(x1,...,xn). More generally, we can evaluate quadratic multi-variate polynomials on ciphertexts provided the resulting value falls within a small set. We present a number of applications of the system: In a database of size n, the total communication in the basic step of the Kushilevitz-Ostrovsky PIR protocol is reduced from $\sqrt{n}$ to $\sqrt[3]{n}$. An efficient election system based on homomorphic encryption where voters do not need to include non-interactive zero knowledge proofs that their ballots are valid. The election system is proved secure without random oracles but still efficient. A protocol for universally verifiable computation.

Fully secure functional encryption: attribute-based encryption and (hierarchical) inner product encryption

Abstract: We present two fully secure functional encryption schemes: a fully secure attribute-based encryption (ABE) scheme and a fully secure (attribute-hiding) predicate encryption (PE) scheme for inner-product predicates. In both cases, previous constructions were only proven to be selectively secure. Both results use novel strategies to adapt the dual system encryption methodology introduced by Waters. We construct our ABE scheme in composite order bilinear groups, and prove its security from three static assumptions. Our ABE scheme supports arbitrary monotone access formulas. Our predicate encryption scheme is constructed via a new approach on bilinear pairings using the notion of dual pairing vector spaces proposed by Okamoto and Takashima.