Aleynikov was found guilty by a Manhattan jury in December 2010 of federal criminal charges relating to the theft of trade secrets and interstate transportation of stolen property.

However, after serving little more than a year of his 97 month sentence, a US Appeals Court overturned the conviction in February. Explaining the decision, the court later said that the laws under which he was charged - the National Stolen Property Act and the Economic Espionage Act - don't apply to his case because Aleynikov stole "purely intangible property embodied in a purely intangible format".

Having won his federal battle, the programmer is now facing a new fight at the State level. He has been arrested and arraigned; charged in New York County Criminal Court with unlawful use of secret scientific material and unlawful duplication of computer related material.

Manhattan District Attorney Cyrus Vance, says: "This code is so highly confidential that it is known in the industry as the firm's 'secret sauce,". Employees who exploit their access to sensitive information should expect to face criminal prosecution in New York State in appropriate cases."

Russian-born Aleynikov worked for Goldman from May 2007 to June 2009, where he developed computer programs supporting the firm's high-frequency trading on various commodities and equities markets.

He then quit Goldman to help develop a HFT platform for Teza Technologies, a Chicago-based start-up formed by ex-Citadel executive Mikhail Malyshev.

Prosecutors alleged that on his last day working for the bank, Aleynikov transferred "substantial portions" of Goldman Sachs's proprietary computer code for its trading platform to an outside computer server in Germany.

He was accused of encrypting the files and transferring them over the Internet and then deleting "the program he used to encrypt the files and deleted his computer's "bash history," which records the most recent commands executed on his computer".

In addition, he had already allegedly transferred "thousands of computer code files" related to the firm's proprietary trading program to his home computers during his two years working there. He did this by e-mailing the code files from his Goldman Sachs account to his personal one and storing versions of the code files on his home computers, laptop, a flash drive and other storage devices, said prosecutors.

On 2 July 2009 Aleynikov flew to Chicago to meet Teza, taking a laptop and storage device allegedly holding the valuable Goldman proprietary code. He was arrested the following day at Newark airport, later charged and eventually convicted before this was overturned.