This book constitutes the proceedings of the 4th International Conference on Cryptology and Information Security in Latin America, LatinCrypt 2015, held in Guadalajara, Mexico, in August 2015.

Cryptographic Protocols.- Efficient RKA-Secure KEM and IBE Schemes Against Invertible Functions.- Simulation-Based Secure Functional Encryption in the Random Oracle Model.- The Simplest Protocol for Oblivious Transfer.- Foundations.- Depth Optimized Efficient Homomorphic Sorting.- The Chain Rule for HILL Pseudoentropy, Revisited.- Post-Quantum Cryptography.- Faster Sieving for Shortest Lattice Vectors Using Spherical Locality-Sensitive Hashing.- FHEW with Efficient Multibit Bootstrapping.- Symmetric Key Cryptanalysis.- Improved Top-Down Techniques in Differential Cryptanalysis.- Algebraic Analysis of the Simon Block Cipher Family.- Cryptanalysis of the Full 8.5-Round REESSE3+ Block Cipher.- Meet-in-the-Middle Attacks on Reduced-Round Hierocrypt-3.- State-Recovery Analysis of Spritz.- We Still Love Pairings Computing Optimal 2-3 Chains for Pairings.- Subgroup Security in Pairing-Based Cryptography.- Curves in Cryptography.- Twisted Hessian Curves.- Improved Sieving on Algebraic Curves.- Attacking a Binary GLS Elliptic Curve with Magma.- Cryptographic Engineering.- Fast Implementation of Curve25519 Using AVX2.- High-Performance Ideal Lattice-Based Cryptography on 8-Bit ATxmega Microcontrollers.- An Efficient Software Implementation of the Hash-Based Signature Scheme MSS and Its Variants.