АБВГДЕЖЗИКЛМНОПРСТУФХЦЧШЭЯ ABCDEFGHIKLMNOPQRSTUVWZ Unauthorized accessUnauthorized access to informationUnauthorized userUnclassified informationUndeniable digital signatureUndeniable signature schemeUnicity distanceUnified threat management (UTM)Unintentional denial-of-serviceUniversal forgeryUnlinkabilityUntracebilityUntrusted networkURL filtering (URLF)UserUser authenticationUser dataUser identification in an information systemUser of signature verification key certificate