This book contains revised selected papers fromthe Second International Conference on Cryptology and Information Security inthe Balkans, Balkan Crypt Sec 2015, held in Koper, Slovenia, in September 2015.The 12 papers presented inthis volume were carefully reviewed and selected from 27 submissions. They areorganized in topical sections named: symmetric key cryptography; cryptanalysis;security and protocols; and implementation and verifiable encryption.