IP-based wireless sensor networks (IP-WSN) are popularly recognized as a global sensor networks infrastructure by combining IPv6 technology with wireless sensor networks (WSN). However, IP-WSN, currently, does not provide security because it is commonly recognized that it is a big burden for IP-WSN to adapt Internet's dominant security protocol. We suggest a security protocol for IP-WSN based on secure sockets layer (SSL). We have developed IP-WSN sensor node hardware with 16-bit MSP430 MCU including 116 KB Flash and 8 KB RAM, and implemented IP-WSN software stack and lightweight SSL components. The resource consumption is around 64 KB of Flash and 7 KB of RAM when it is used that ECC for key-exchange and authentication, RC4 for data encryption, and MD5 for hashing. And it takes total 2 s for a full SSL handshake and a 127 bytes packet transfer. It can make IP-WSN secure and be used for the public and private services such as military observation, healthcare, and home-network.