Instant messenger is an IM application that allows communication in a secured manner. A secured private IM is needed to ensure data transmission between sender and recipient more secure. This paper presents a secure IM architecture. A secure architecture is divided into four modules; chat module, transceiver module, secure module, and routing module. In this research, hash algorithm was applied in secure module. The main function of hash algorithm is to encrypt and convert into hash value. The purpose of this encryption is to ensure unauthorized person cannot view the original data or information through the network. IM application was developed and tested. The result indicates this architecture and hash algorithm able to improve level of data security.