Parisa remembers the precise moment she heard her first song by Shahin Najafi, an Iranian rapper living in exile in Germany, on her illegal satellite television in the small city of Karadj, west of Tehran.
“His words cut through me like a knife,” she said.
Parisa, a 24-year-old university student, stayed up long after midnight one night, when the Internet connection was faster, and spent six hours downloading Mr. Najafi’s songs.
Since the Iranian authorities have cracked down on the demonstrations that rocked the country after a disputed election a year ago, a flood of protest music has rushed in to comfort and inspire the opposition. If anything, as the street protests have been silenced, the music has grown louder and angrier.
The government has tried all manner of methods to mute what has become known as “resistance music.” It has blocked Web sites used to download songs and shut down social networking sites, which the opposition also used to organize protests and distribute videos of government and paramilitary violence.
In April, a shadowy pro-government group that calls itself “the cyber army” shut down Mr. Najafi’s Web site. The group, which hacked Iranian Twitter in December, left a message saying the site had been “conquered by anonymous soldiers of Imam Zaman,” a reference to the Shiite messiah.