Should old secrets stay secret what happens when the past becomes readable

[FewShot]

TL;DR

• Harvest now, decrypt later means encrypted data recorded today could become readable years from now, turning yesterday's private messages into tomorrow's open books
• History has done this before: the US Venona project decrypted parts of Soviet messages decades after they were sent, and the wartime Ultra secret about Enigma stayed hidden until 1974
• The moral questions are rich: do people have a right for old secrets to stay secret, does the public sometimes have a right to know, and who should decide
• Philosopher Helen Nissenbaum's idea of contextual integrity suggests privacy is about information flowing appropriately, which helps explain why exposure years later can still feel like a violation
• Practical lessons include sharing less sensitive data, deleting what is no longer needed and supporting migration to post quantum encryption for long lived secrets

A time capsule nobody agreed to

Imagine sealing a letter in an envelope that you believe nobody can ever open. You write openly about your fears, your mistakes, your health or your feelings about colleagues. Years later, someone you never met opens it and reads every word. That is roughly what harvest now, decrypt later could mean for some of the digital messages we send today

Security agencies warn that adversaries may already be recording encrypted internet traffic, storing it in the hope that future quantum computers will unlock it. If that happens, messages protected by today's public key encryption could become readable long after they were sent. Not every message is at risk, since much traffic is already moving to post quantum protection and symmetric encryption remains strong. But the idea raises fascinating moral questions

This thread explores those questions rather than the technical details. Should old secrets stay secret? Is there a difference between a government reading a spy's message from 1970 and a stranger reading your private chat from 2025? What does privacy mean when time can undo it? I hope members will share their own views

History has been here before

The idea of decrypting old secrets is not new. During the Second World War, Allied codebreakers at Bletchley Park broke German Enigma and Lorenz ciphers, producing intelligence known as Ultra. The fact that these codes had been broken remained officially secret until 1974, when F W Winterbotham published The Ultra Secret. Many people who had worked at Bletchley Park kept silent for decades, even with their own families

The Venona project offers an even closer parallel. Starting in 1943, the US Army's Signal Intelligence Service began studying encrypted Soviet communications it had intercepted. Because Soviet operators had reused some one time pad material, analysts were able over many years to decrypt portions of thousands of messages. The project continued until 1980, and its existence and many decrypts were made public in 1995, revealing details of Soviet espionage from decades earlier

Venona shows both sides of the issue. On one hand, it helped identify spies and shaped historical understanding of the Cold War. On the other, decrypted messages sometimes contained ambiguous references to cover names, and historians still debate how some individuals should be judged. Old secrets, once revealed, do not always come with clear context

Why exposure years later still hurts

Philosopher Helen Nissenbaum developed the idea of contextual integrity to explain privacy. She argues that privacy is not simply about keeping information secret but about ensuring it flows in ways appropriate to the context in which it was shared. Medical details shared with a doctor, confidences shared with a friend and opinions shared in a private chat each carry expectations about who will see them. A violation occurs when information moves outside those expectations

This helps explain why decryption years later can still feel wrong. The context in which a message was written, such as a trusted conversation between friends, does not disappear just because time passes. Reading it later, out of context and without consent, breaks the norms under which it was shared. Even if the information seems harmless, the violation of expectations matters

Time can also change how information is judged. Opinions acceptable in one era may seem offensive in another, and people grow and change. A teenager's private message, read twenty years later, may say little about the adult they became. Exposure could punish people for who they used to be

Power dynamics shape the harm. Exposure of a powerful official's old messages may serve public accountability, while exposure of an ordinary person's private life may simply cause pain. The same act of decryption can have very different moral weight depending on who is affected. Ethics rarely offers one rule for every case

Arguments for keeping old secrets secret

Several moral arguments support protecting old secrets. Respect for autonomy suggests people should control information about themselves, including their past. Fairness suggests people should not be judged by private words they never expected others to see. Trust suggests that if people believe their private communications will eventually be exposed, they will become guarded and less honest, damaging relationships and public life

There is also the matter of third parties. Old messages often mention other people who never agreed to be discussed. A decrypted chat might reveal a friend's illness, a colleague's struggles or a family member's secret. Their privacy is affected too, often without any knowledge or recourse

Trust between generations is another consideration. Families often keep letters and diaries private out of respect, even after a death. If digital messages become readable without anyone's consent, those family choices are taken away. Something valuable about how we honour the dead could be lost

European law reflects some of these values. In 2014, the Court of Justice of the European Union ruled in the Google Spain case that individuals could in some circumstances ask search engines to remove links to outdated or irrelevant information about them. The General Data Protection Regulation later included a right to erasure. These rules reflect a belief that the past should not always follow us forever

Arguments for revealing some old secrets

There are also strong arguments for revealing certain secrets. Historians depend on access to records to understand the past, including uncomfortable truths about wars, governments and institutions. Many countries release government records after a set period, and the UK has been moving from a 30 year rule to a 20 year rule for transferring records to its National Archives. Secrecy forever would deprive societies of their history

Accountability is another argument. Hidden wrongdoing, such as corruption, abuse or crimes, may only come to light when old records are revealed. Victims may gain recognition and justice, sometimes decades later. A world where all secrets stayed secret forever could shelter wrongdoers as well as protect the innocent

Public interest can shift over time. Information that was legitimately secret during a conflict may become important for understanding history once the conflict ends. Many democracies balance these concerns through declassification rules, archival law and public interest tests. Deciding which secrets deserve protection is a judgement, not a formula

Consent is a useful test. Many people are comfortable with their records being opened after their death or after a long period, provided they agreed in advance or the law set clear terms. Archives often respect conditions set by donors. Harvest now, decrypt later involves no such agreement, which is what makes it feel so different

Who decides

A crucial difference between historical declassification and harvest now, decrypt later is who decides. When governments release archives, they usually follow laws, review processes and sometimes consult affected families. When an adversary decrypts stored traffic with a quantum computer, there is no process, no consent and no accountability. The information simply becomes available to whoever holds it

This raises questions about power. Those with the most advanced technology could gain access to vast amounts of historical private information, while ordinary people would have no way to know what had been read. Concentrated access to secrets is a form of power. That makes post quantum migration not only a technical issue but a question of fairness and democratic control

Questions of fairness also arise between countries. Nations with advanced quantum capabilities could read the past communications of nations without them. That asymmetry could affect diplomacy and trust for years. International norms on the use of decrypted historical data do not yet exist

Practical reflections

What can individuals and organisations do with these ideas? The first step is recognising that some data has a very long shelf life. Medical records, legal documents, personal letters and sensitive business information may need protection for decades. Organisations handling such data are being encouraged to migrate early to post quantum encryption

A second step is sharing less. Data that is never sent or stored cannot be exposed later. Thinking twice before sending deeply personal information electronically, and deleting old data that is no longer needed, reduces future risk. These habits are good privacy practice regardless of quantum computers

A third step is supporting good policy. Strong data protection laws, sensible retention limits and investment in secure infrastructure all help. Public debate about how long secrets should last, and who should be able to read them, is healthy. Q-Day gives that debate a new urgency

Questions to discuss

• Would you be comfortable if your messages from ten years ago became readable to strangers
• Should historians eventually have access to private communications from today
• Is it fair to judge people by private words written in a different era
• Who, if anyone, should decide which old secrets are revealed
• Does knowing about harvest now, decrypt later change how you communicate

Closing thoughts

The prospect of old encrypted messages becoming readable turns abstract technology into a deeply human question. History shows that past secrets can be revealed decades later, with both benefits and harms. Ideas like contextual integrity help explain why privacy violations hurt even when time has passed. Balancing respect for individuals with the value of history and accountability is a challenge worth discussing openly

Please share your views in the replies, including personal reflections if you are comfortable. Disagreement is welcome, since thoughtful people come to different conclusions on questions like these. Kindness and respect make the conversation better for everyone


Further reading

• Helen Nissenbaum, Privacy in Context: Technology, Policy, and the Integrity of Social Life, 2010
• NSA and CIA, Venona documents release, 1995
• F W Winterbotham, The Ultra Secret, 1974
• Court of Justice of the European Union, Google Spain v AEPD and Mario Costeja Gonzalez, 2014
• UK National Archives, transition to the 20 year rule