Many signciyption schemes have been proposed to provide authentication and confidentiality of a message efficiently. Among such a scheme, identity-based cryptography is one of the public key cryptography that does not require the certificate for a public key and pre-compute key pair. This scheme uses the public key that can be generated from an arbitrary identifier such as an email address, while the private key is derived by a trusted private key generator as occasion demands. In this paper, we propose identity-based KCDSA(Korean certificate-based digital signature algorithm) signcryption schemes providing the semantic security. Also, the proposed schemes support either the public veiifiability or the forward secrecy. The proposed schemes are based on the standardized digital signature scheme and can be applied to the established KCDSA systems.