Mr Sklyarov's arrest has sparked demonstrations
Russian programmer Dmitry Sklyarov and his Moscow-based employer, Elcomsoft, have been charged with breaking controversial US copyright laws.
The 26-year-old programmer was arrested last month shortly after presenting a paper to a conference on the encryption methods used to protect electronic books.
Mr Sklyarov has been indicted on five charges and if found guilty on all of them could face up to 25 years in jail.
The cause of the programmer has been taken up by freedom of speech advocates and cyber libertarians who are planning demonstrations to protest against his arrest and indictment.
Copyright controversy
Mr Sklyarov, who is free on $50,000 bail but must remain in northern California, was formally charged on Wednesday with violating the Digital Millennium Copyright Act.
Mr Sklyarov is the first person to be charged under the DMCA, which took effect last year.
The Act makes it a crime to distribute tools that can be used to circumvent copyright controls on digital products such as electronic books, encrypted music files and DVDs.
On 16 July FBI agents arrested Mr Sklyarov, who had travelled to the US for a technical conference at which he was to present a paper on the encryption methods some companies have chosen to protect online works.
He was arrested at the urging of Adobe which said the Advanced eBook Processor software that he had co-written, and his employer Elcomsoft had been selling, could be used to break the encryption systems being used to stop electronic books being illegally copied.
Adobe withdrew its complaints following lobbying by the civil and cyber-liberties group Electronic Frontier Foundation. However, the US Government has pushed on with its prosecution of Mr Sklyarov.
Mr Sklyarov has denied the allegations.
"We will vigorously contest these charges," said Mr Sklyarov's lawyer Joseph Burton of law firm Duane Morris.
"Even if one were to ignore the serious legal questions involving the DMCA, this case hardly cries out for criminal prosecution," he said.
He added that the law firm was working to ensure that Mr Sklyarov's wife, two-year-old son and four-month-old daughter travel to California in time for the court appearance.
Demonstrations to protest against the treatment of Mr Sklyarov and the DMCA are being planned for Thursday. Protesters are due to gather in Moscow, London, Edinburgh, Boston, San Francisco, Los Angeles and in Nevada at the annual Burning Man arts festival.