Best way for client to access S3 storage file in a specific bucket

THanks in advance.... I would like to provide security for al my URLS of s3 bucket.IN my bucket around 10 files are there and each file is to be restricted to limited users.Dont want make my server as proxy for validation to access the files..please help me with best way to solve this.

Ex: File to be accessed by only 3 users & FIle2 to be accessed by 5 users.but all files in same bucket.