The report on security, the seventh in the UK Government's Scotland Analysis series, looks at policing and intelligence in the event of Scotland becoming independent and its theme is an echo of the No campaign slogan - "safer together".
It concludes that threats to Scotland from organised crime gangs, cyber criminals and global terrorism "are best confronted with Scotland inside the UK".
Home Secretary Theresa May launched the paper in Edinburgh with the warning the UK's current intelligence and security network would be difficult to replicate in an independent Scotland.
Her arguments were dismissed by the SNP, which said Scotland was already an independent jurisdiction for policing and already has cross-border cooperation on counter-terrorism and other issues.
Ms May rejected nationalist arguments that Scotland may face a diminished threat by rejecting nuclear weapons and shunning "illegal wars" such as the Iraq conflict. She said some terrorists have an issue with the way of life in the West rather than specific grievances about foreign policy.
She said: "I don't think it is possible to guarantee the threat would diminish."
She struck a more conciliatory tone than Defence Secretary Philip Hammond on a similar recent mission over the Border, but the report stated: "Of note among the UK's international relationships is the one it shares with Australia, Canada, New Zealand and the USA, also known as Five-Eyes.
"There would be no automatic right of entry to the Five-Eyes community for an independent Scottish state. The intelligence these countries choose to collect and share is based on whether it is in their national interest to do so.
"Entry is by invitation only. No new country has been admitted for decades. There would have to be a benefit to the other members of an independent nation joining - its unique contribution. An independent Scottish state may not possess the capabilities for this, and any new capabilities would take time to mature."
The same countries operate a police intelligence sharing group called the Strategic Alliance Group.
It was put to Ms May it was odd London might be prepared to share police and security intelligence with a nation of five million people at the other end of the globe, but not with a nation of five million people in the same island.
She said: "I would expect that ... the UK would look to co-operate with it but there are particular arrangements for working together and sharing data and membership of these groups would not be automatic."
Former Home Secretary Lord Reid, a Scottish Labour politician, said: "A separate Scotland would be less secure than at present and less well-placed to counter many security threats.
SNP Justice convener Christine Grahame said: "This is Project Fear at its worst. Trying to politicise issues of security and anti-terrorism in this way is the height of irresponsibility. This paper ignores the fact Scotland is already an independent jurisdiction for justice and policing, and as such we already have lots of cross-border cooperation on counter-terrorism and other issues which will continue in an independent Scotland.
"It beggars belief Theresa May feels able to lecture anyone on arresting people in other countries after she was forced into an embarrassing U-turn on the European Arrest Warrant."
Justice Secretary Kenny MacAskill said: "An independent Scotland will have first rate security arrangements to counter any threats we may face. We will continue to work in close collaboration with the rest of the UK and international partners on security and intelligence matters, which is in everyone's interests."