The progress of modern science and technology has accelerated the development of communication, providing more focus on the security of data transmission. Although there are many recognized encryption techniques, more high-performance algorithms are required to withstand the sophisticated analysis and cracking techniques. In this paper, we propose an innovative algorithm that combines with Core Adaptive Fourier Decomposition (Core-AFD) for text encryption. In addition, two versions of algorithm, initial version and enhanced version, are discussed for different forms and strength of the secret key and ciphertext. Due to the one-to-one correspondence between the decomposition and the error terms, the encryption algorithm is theoretically feasible and safe. The algorithm is further demonstrated by conducting experiments on text encryption with different lengths. The results are promising. Finally, the time complexity of cracking our algorithm in different cases is given.