Huawei Technologies Co. has turned to a blend of wit, sarcasm and defiance to publicly fight allegations that the world's largest maker of telecommunications equipment is spying for China. It's a remarkable shift for a giant whose founder, Ren Zhengfei, spurned the media and avoided overt displays of power.

Rotating Chairman Guo Ping encapsulates its new credo. Striding onstage before hundreds of people at the phone industry's flagship conference this week, he opened with a joke directly addressing the company's demons: "There has never been more interest in Huawei. We must be doing something right."

Guo laid into the U.S., which vaulted Huawei into the public eye when it orchestrated last year's arrest by Canadian authorities of Chief Financial Officer Meng Wanzhou, who is also the founder's daughter. He urged the crowd in Barcelona, Spain, to reject using politics to manage cybersecurity and turned the spotlight on America, which he said was spying on its own corporations. Some audience members applauded.