This paper presents an ECC (Elliptic Curve Cryptography) based self-certified convertible authenticated encryption (CAE) scheme with computational secrecy. Combining the merits of self-certified public key cryptosystems, the proposed scheme has the property that authenticating the public key and verifying the signature can be simultaneously carried out within one step, which helps reducing computation efforts. Based on the ECC, our scheme can provide crucial benefits to those applications of mobile devices with the limited computing power and insufficient storage space for its shorter key length. In addition, the computational secrecy also ensures that the generated authenticated ciphertext is computationally indistinguishable with respect to two candidate messages.