Abstract: Provided is a content recommendation method. The content recommendation method includes: receiving, by a user terminal, text information from a user through a text input window of a chatting room, outputting, by the user terminal, a first content set including at least a part of contents related to keyword information to be mapped to the text information, outputting, by the user terminal, a first preview content for a first content included in the first content set, receiving, by the user terminal, an interaction from the user, and in response to the interaction, outputting, by the user terminal, a second preview content for a second content to replace the first preview content, wherein the second content is a content related to the keyword information.

Abstract: Provided are a method and server for providing a content list. The method and server for providing a content list includes: providing source content to a chat room, receiving a request for providing a content list related to the source content from a first terminal of a first member; providing at least one of a first content list including at least one keyword-related content selected from among the entire contents stored in the server based on a keyword of the source content and a second content list including at least one group-related content belonging to the same group as a group of the source content among the entire contents, receiving information on selection content selected by the first member among the contents included in the at least one content list, from the first terminal, and providing the selection content to the chat room.

Abstract: A blockchain based integrated identity and authentication management service method is a method of allowing a user who is subscribed to a provider to use a partner service through a virtual ID registered in a private blockchain managed and operated by the provider without subscribing to the partner service, in order to use the partner service associated with the provider. The user creates the virtual ID and registers the virtual ID in the private blockchain through the provider, and the user sends the virtual ID to a partner and requests a service. The partner verifies the virtual ID through the private blockchain, acquires a public key of the user from the private blockchain, and provides the service to the user via mutual authentication with the user, wherein additional personal information required is obtained through a separate personal information database held by the provider, not by the private blockchain.