Wireless sensor networks (WSN) are being used in a wide range of application areas, such as national security, attack and disaster preparation and response, military surveillance, and medical care. All these applications require a certain level of reliability and security during data transmission. Data loss or corruption in WSN may be due to hardware failures, wireless channel noises, or malicious attacks. To overcome all these inevitable factors, we have recently presented a selective hybrid cipher (SHC) based algorithm that integrates selective encryption and forward error correction codes for achieving simultaneously secure and reliable data transmission in resource-constrained WSN. In this work, we implement an instance of the SHC-based data transmission mechanism using AES and Reed-Solomon codes, and analyze its security property using the linear cryptanalysis (LC) technique. The LC analysis results of the SHC-based algorithm are compared with those of the traditional DES and AES algorithms. Comparison results show that the SHC design has inherent LC attack resistance and is stronger than DES. The results also show that the proposed SHC-based mechanism can provide security-level that is comparable to AES with the improvement in computational complexity and reduction in energy consumption.