Jonathan Hipkiss, 42, formerly of Southwell, became the first person in Notts, and only the third in the UK, to be convicted of failing to disclose an encrypted key to restricted information.
The married father had refused to hand over the key to a programme that protected his sickening collection of photos and videos, some judged to be grade 5 – the worst category.
A specialist finally unlocked the code 12 months later.
Meanwhile, Hipkiss used a new computer bought for his son to download more images, Nottingham Crown Court heard.
He admitted 15 counts of making indecent photographs and three of possessing them.
Judge Michael Stokes, QC, who sentenced him to a year in prison, said: “You have demonstrated a level of manipulation born out of your profession as a web engineer.
“You were seen by police in March last year. It wasn’t until March this year you admitted you were doing that which has now been demonstrated.”
On one computer, there were 1,286 images categorised at level one – the least serious. There were 74 at level two, 30 at level three, 39 at level four and six at level five.
Describing the images as “absolutely disgusting”, the judge said Hipkiss had lied to his wife of 13 years that he was innocent.
When confronted with the expert analysis, Hipkiss, now of Birchfield Road, Redditch, confessed to his wife and she left him.
Defending, Julie Warburton said: “It took him a year to admit what he had done. What was holding him back was essentially the knowledge that the moment he spoke the truth about these matters, his family would disintegrate.”
And yet he continued doing it!
The charge of failing to disclose an encrypted key to restricted information was only introduced in October, 2007.
Speaking after Hipkiss’s sentencing Detective Sergeant Harry Parsonage, of Notts Police’s e-Crime Unit, said: “This is one of the most complicated examinations of computer files that I have seen in the ten years that I have been in charge of the unit.
“It required an in depth, detailed look into a large number of items over several months.
“Hipkiss was put into a position where he had no choice than to admit what he had done, after our officers had been able to piece together many fragments of evidence to show he had intentionally downloaded and saved these files.”
Detective Inspector Ian Winton, of the Sexual Exploitation investigation Unit, said: “This case shows that no matter what lengths people think they can take to hide child abuse images, we will find them.”
Ruth Allen, head of intelligence for the Child Exploitation and Online Protection Centre, known as Ceop, said: “Any individual who believes they can evade justice will no longer be able to hide behind the technology they use.”
Hipkiss was also disqualified from working with children and must sign the sex offenders’ register for ten years.