Elliptic Curve Cryptography (ECC) is a public-key cryptosystem which can be used for message encryption, key agreement
protocols and digital signature applications. ECC offers high level of security with smaller key sizes makes it ideal fo
r applications which run on small devices that have power and memory constraints such as smart cards and cell phones. Encoding (converting a plaintext message to a point) and Decoding (converting a point to a plaintext message) are important functions in encryption and decryption schemes using ECC before transmission over public networks and unsecured channels. In this paper, we proposed a text message encoding scheme which is based on computational operations on points that lie on a predefined elliptic curve (EC) . For any ECC-based encryption scheme, the mapping methodology of a plaintext message onto a coordinate on an affine curve is a mandatory prerequisite. ASCII character codes are considered for the
mapping method to convert a plaintext message into coordinates of the predefined EC-points. Discussing the mapping methodology, creating the mapping table and the converting process are given in detail along with their implementations.