@techreport{TR-IC-PFG-18-28, number = {IC-PFG-18-28}, author = {Vitor {Falcão da Rocha} and Julio {López}}, title = {{An Overview on Homomorphic Encryption Algorithms}}, month = {January}, year = {2019}, institution = {Institute of Computing, University of Campinas}, note = {In English, 23 pages. \par\selectlanguage{english}\textbf{Abstract} Homomorphic encryption is a cryptographic construction that allows an application to operate on ecrypted data, instead of the raw data itself. The possibility of homomorphic encryption had long been studied due to the applications it enables, especially the outsourcing of computing on sensitive data, while preserving the privacy of the data. Not until 2009 a fully homomorphic encryption scheme (FHE) was proposed by Craig Gentry, though not practical, this scheme paved the way for other schemes, both based on Gentry's ideas and others based on new ideas In parallel, some applications were developed to operate on data encrypted by those FHE schemes, proving that FHE could power practical applications, in a more privacy preserving fashion. This paper presents the concepts that support modern homomorphic encryption schemes, together with the description of some FHE schemes. In addition, some practical applications for processing sensitive data are presented. } }