Supporters of jailed Russian cryptographer Dmitry Sklyarov will be staging a protest outside the US embassy in London at lunch time on Friday.
The Russian software programmer has been held in an Oklahoma prison for the last 16 days, following his arrest at the Def Con hacker conference in Las Vegas.
The US Department of Justice (DoJ) is planning to take him to court on charges of circumventing US copyright with his Advanced eBook processor which allows encrypted Adobe PDF eBooks to be copied.
Software company Adobe dropped its charges against Sklyarov in the face of strong protest from the hacker community, but the DoJ still plans to go ahead with the prosecution.
Supporters of Sklyarov have this week been calling for Adobe to contribute to the legal defence fund for the programmer. Reuters reported that a lawyer for the Electronic Frontier Foundation, one of Sklyarov's biggest backers said: "I think it would be an opportunity for Adobe to put its money where its mouth is."
Sklyarov has also drawn support from other leading industry figures, including PGP creator Phil Zimmerman, cryptographer Bruce Schneier and open source godfather Richard Stallman.
Adobe has remained tight-lipped as to whether it will contribute to the defence fund.
The protestors will be meeting at 12.30pm on Friday outside Hyde Park Corner underground station. More details are available here.
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