Early Symmetric Cryptography (ESC) is a prestigious bi-annual event (2008, 2010, 2013) taking place in Luxembourg and paired with Dagstuhl seminars (2007, 2009, 2012) on symmetric cryptography. The first two editions of this workshop were sponsored by FNR. We will organize the 4th Early Symmetric Cryptography (ESC) seminar in Clervaux in January 2015.Cryptography deals with secure communication in adversarial environments as well as protecting information in storage. It is the key ingredient of information security. Applications such as electronic commerce, e-banking, secure communications (ex. mobile phones, Skype, etc.) are made possible due to advances in applied cryptography. The seminar is concentrating on:• symmetric primitives (block and stream ciphers, message authentication codes and hash functions), and• complex cryptosystems and cryptographic protocols employing these primitives• algorithmic challenges in public and symmetric cryptography.Special sub-topics that will be explored this year would be:-Evaluation of submissions for the authenticated encryption competition (CAESAR) sponsored by NIST.-Evaluation of candidates for the currently running password-hashing competition.-Design and analysis of lightweight cryptography (this topic is in line with the CORE ACRYPT project).The aim of the workshop is to bring together leading experts and talented junior researchers. The exceptional feature of this seminar is that at least half of the participants are also speakers, since they are invited to give presentations on their most recent or on-going research.