> ## Content Index > Fetch the complete content index at: https://z-text.org/llms.txt > Use this file to discover other available public pages before exploring further. # Postcard From 2035 #3: They Didn’t Need to Read It - URL: https://z-text.org/postcard-from-2035-zero-metadata/ - Published: 2026-10-16T07:08:14.000Z - Updated: 2026-10-16T15:38:37.000Z - Description: A postcard from 2035: they couldn’t read your messages. They didn’t need to. What metadata reveals, what an ex-NSA chief said about it, and how Z-TEXT shields who talks to whom. - Author: Eric Pierrot - Founder, Z-TEXT LLC — building privacy tools without phone numbers, email, or metadata. - Tags: Postcard from 2035, Metadata, Privacy, zk-SNARKs [ ![Get Z-TEXT on Google Play](https://storage.ghost.io/c/fd/15/fd15bb3d-d8d8-469e-8b80-b94dae7aa4cd/content/images/2026/10/GetItOnGooglePlay_Badge_Web_color_English.png) ](https://play.google.com/store/apps/details?id=com.bitcoinz.wallet&ref=z-text.org) ![Z-TEXT privacy bird](https://storage.ghost.io/c/fd/15/fd15bb3d-d8d8-469e-8b80-b94dae7aa4cd/content/images/2026/05/my-bird.png) Postcard #3 just arrived from 2035\. A joke on the front, a real fact on the back. This one is about the part of your messages that encryption doesn't hide. Z-TEXT is a privacy messenger built on the BitcoinZ blockchain. Z-TEXT needs no phone number, no email and no SIM, and Z-TEXT is built for zero metadata. In short Metadata is everything around a message: who you talk to, when, how often and from where. Encryption hides the words, not the metadata. In 2014, former NSA and CIA director Michael Hayden said "We kill people based on metadata." Z-TEXT sends messages as shielded BitcoinZ transactions, where zk-SNARKs keep the sender and the recipient encrypted on the blockchain. ## ❓ 1\. What does postcard #3 say? "Dear 2026, they couldn't read your messages. They didn't need to. In 2035, we know: who, when and where was enough. Ours had no envelope." The year 2035 is invented. The quote on the back is real. ## ❓ 2\. What is metadata, in plain words? Think of a letter. The words inside are the content. The envelope is the metadata: who sent it, who received it, when, and from which town. End-to-end encryption locks the letter. But in most messengers, the envelope stays readable to the service, and often to anyone who can ask the service for its records. And the envelope says a lot. Mini-resume Metadata is the data around a message: sender, recipient, time, frequency and location. End-to-end encryption protects the content of a message, but not its metadata. In most messaging apps, metadata remains visible to the service provider. ## ❓ 3\. Who said "We kill people based on metadata"? Michael Hayden said it. Hayden ran the US National Security Agency (NSA) from 1999 to 2005 and the CIA from 2006 to 2009\. (Source: [ABC News](https://abcnews.com/blogs/headlines/2014/05/ex-nsa-chief-we-kill-people-based-on-metadata?ref=z-text.org)) He said it in April 2014, in a debate at Johns Hopkins University with Georgetown law professor David Cole. Cole had argued that metadata reveals a lot about a person. Hayden answered: "We kill people based on metadata." (Source: [Just Security](https://www.justsecurity.org/10311/michael-hayden-kill-people-based-metadata/?ref=z-text.org)) To be fair to Hayden, his full sentence went on: "But that's not what we do with this metadata." He meant the NSA's bulk phone records. (Source: [The Hacker News](https://thehackernews.com/2014/05/ex-nsa-director-admits-we-kill-people.html?ref=z-text.org)) Our view: the second half doesn't make the first half less true. It confirms what metadata is worth. Mini-resume Former NSA and CIA director Michael Hayden said "We kill people based on metadata" in April 2014, during a debate at Johns Hopkins University with law professor David Cole. Hayden added that this was not what the NSA did with its bulk phone metadata. The quote shows how much intelligence agencies value metadata. ## ❓ 4\. What can metadata reveal about you? Stanford researchers tested it. More than 800 volunteers shared their phone logs: about 250,000 calls and 1.2 million texts. No content, just metadata. The study appeared in the journal PNAS in 2016\. (Source: [Stanford Report](https://news.stanford.edu/stories/2016/05/stanford-computer-scientists-show-telephone-metadata-can-reveal-surprisingly-sensitive-personal-information?ref=z-text.org)) From call patterns alone, the researchers could infer sensitive facts. One participant called a cardiologist, a pharmacy and a heart-monitoring hotline. The likely conclusion: a heart condition. (Source: [WeLiveSecurity](https://www.welivesecurity.com/2016/05/19/metadata-phone-calls-reveals-personal-information/?ref=z-text.org)) Nobody read a single word. They didn't need to. Mini-resume A 2016 Stanford study published in PNAS analyzed the phone metadata of more than 800 volunteers, covering about 250,000 calls and 1.2 million texts. Without reading any content, researchers inferred sensitive personal information, such as a likely heart condition from a pattern of calls to a cardiologist, a pharmacy and a heart-monitoring hotline. Watch postcard #3 in 15 seconds: ## ❓ 5\. How does Z-TEXT reduce metadata? Z-TEXT sends each message as a shielded transaction on the BitcoinZ blockchain. In a shielded transaction, the data is encrypted on the blockchain, and zk-SNARKs prove the transaction is valid without revealing it. (Source: [Electric Coin Co](https://z.cash/learn/what-are-zk-snarks/?ref=z-text.org)) zk-SNARKs are zero-knowledge proofs: a way to prove something is true without showing the details. For Z-TEXT, that means the blockchain doesn't show who wrote to whom. Z-TEXT also asks for no phone number, no email and no SIM. So there is no contact list and no phone number to link your messages to your name. Yes, we sell a messenger, so of course we'd say this. But you don't have to take our word for it: a shielded transaction on the BitcoinZ blockchain is public, and you can look at one yourself. Mini-resume Z-TEXT sends messages as shielded transactions on the BitcoinZ blockchain. zk-SNARKs zero-knowledge proofs keep the sender and recipient encrypted on the blockchain while proving each transaction is valid. Z-TEXT asks for no phone number, no email and no SIM, so messages are not tied to a phone number or a contact list. Honest note: Z-TEXT reduces metadata on the blockchain layer. Your internet provider can still see that your device connects to the network. And the Z-TEXT app has not been independently audited yet. A public bug bounty is open. This is card #3 of the series Postcard from 2035\. Card #1 was about quantum computers: [Your Chats Got Opened. Ours Are OK.](https://z-text.org/postcard-from-2035-harvest-now-decrypt-later/) Card #2 was about phone numbers: [No One Asks for Your Phone Number.](https://z-text.org/postcard-from-2035-no-phone-number/) Z-TEXT runs on Android, macOS, Windows and Linux: [z-text.com/downloads](https://z-text.com/downloads?ref=z-text.org). BitcoinZ lives at [getbtcz.com](https://getbtcz.com/?ref=z-text.org). ### Sources 1. [ABC News, Ex-NSA Chief: 'We Kill People Based on Metadata' (May 2014)](https://abcnews.com/blogs/headlines/2014/05/ex-nsa-chief-we-kill-people-based-on-metadata?ref=z-text.org) 2. [Just Security, David Cole: Michael Hayden: “We Kill People Based on Metadata” (May 2014)](https://www.justsecurity.org/10311/michael-hayden-kill-people-based-metadata/?ref=z-text.org) 3. [The Hacker News, Ex-NSA Director admits "We kill people based on metadata" (May 2014)](https://thehackernews.com/2014/05/ex-nsa-director-admits-we-kill-people.html?ref=z-text.org) 4. [Stanford Report, Telephone metadata can reveal surprisingly sensitive personal information (May 2016)](https://news.stanford.edu/stories/2016/05/stanford-computer-scientists-show-telephone-metadata-can-reveal-surprisingly-sensitive-personal-information?ref=z-text.org) 5. [WeLiveSecurity (ESET), on the Stanford phone metadata study (May 2016)](https://www.welivesecurity.com/2016/05/19/metadata-phone-calls-reveals-personal-information/?ref=z-text.org) 6. [Electric Coin Co, What are zk-SNARKs?](https://z.cash/learn/what-are-zk-snarks/?ref=z-text.org) 7. [Z-TEXT](https://z-text.com/?ref=z-text.org) · [BitcoinZ](https://getbtcz.com/?ref=z-text.org) Keywords: zero metadata messenger · metadata privacy · private messaging app · secure messaging app · zero-knowledge proof messenger · blockchain messenger · no phone number messaging app · Signal alternative 🔗 **Also read:** [Signal vs Z-TEXT](https://z-text.org/signal-vs-z-text-gold-standard-vs-next-generation/) · [WhatsApp vs Z-TEXT](https://z-text.org/whatsapp-vs-z-text-you-are-the-product-vs-you-are-the-user/) · [Session vs Z-TEXT](https://z-text.org/session-vs-z-text-two-no-phone-messengers-compared/) · [Telegram vs Z-TEXT](https://z-text.org/telegram-vs-z-text/) · [Four Apps Replaced](https://z-text.org/one-blockchain-messenger-four-apps-replaced/) · [The Third Man](https://z-text.org/the-third-man-had-tunnels-z-text-has-blockchain-2/) 🔗 Share this postcard [X](#) [Telegram](#) [WhatsApp](#) [Facebook](#) [LinkedIn](#) [Copy link](#) [👉 No Phone. No Email. No SIM. Zero Metadata. Just Z-TEXT.](https://z-text.com/packages?ref=z-text.org) ![Z-TEXT privacy bird](https://storage.ghost.io/c/fd/15/fd15bb3d-d8d8-469e-8b80-b94dae7aa4cd/content/images/2026/05/my-bird.png)