Digital watermarking provides copyright protection for digital image by hiding appropriate information in the original image. Hence copyright protection has become essential to avoid unauthorized replication problem. In paper produce improvements on generating digital watermark key generation. Firstly, add another parameter to increase the security features on the encryption stage, based on Lagrange polynomial under time condition to increase the robust in front of the attacker. Secondly proposed new improvement on gray watermark image (logo), that aim to reduce the logo size that embedded in the host image by analysis the feature and extract the sensitive positions only. The experimental results give efficient and acceptable result based on most popular image processing measures which give approximately same efficient results with increase the security and complexity features.