☑️The ZK Email Stamp
Verify your Amazon and Uber activity using zero-knowledge email analysis provided by ZK Email. Earn up to 6 different credentials based on your Amazon shipping and Uber rides, all while keeping your email data completely private.
Time Required: 5-10 minutes
Cost: Free
Difficulty: Beginner-friendly
Privacy Level: High (zero-knowledge proofs)
Prerequisites:
Active Google Gmail account with email history
Amazon shipping confirmations in your email inbox or archive
Uber ride receipts in your email’s inbox or archive
Web browser (Chrome, Firefox, Safari, or Edge)
Stable internet connection
Step-by-Step Guide:
Start the Verification Process
Click the "Check Eligibility" button in your Human Passport dashboard
You'll be redirected to the ZK Email verification interface
Review the privacy notice explaining how your data is protected
What's happening: ZK Email prepares to analyze your email patterns without accessing your actual email content
Email Analysis & Credential Assignment
ZK Email scans your inbox for Amazon and Uber patterns:
Looks for purchase confirmations from Amazon in your inbox and archive
Searches for ride receipts from Uber in your inbox or archive
Analysis typically takes anywhere from 15 seconds to a couple of minutes
View your results:
Amazon credentials earned (if any)
Uber credentials earned (if any)
Total points added to your Passport score
Technical Details
Supported Email Providers
Primary: Gmail (Google Workspace accounts)
Coming Soon: Outlook
Emails that are scanned
All emails in the Inbox
All emails that are archived
No deleted emails
Understanding Your Credentials
Amazon Credentials
Casual Purchaser
1+ purchases
1
Basic e-commerce engagement
Regular Customer
10+ purchases
0.6
Consistent shopping activity
Heavy User
50+ purchases
0.4
Substantial e-commerce history
Uber Credentials
Occasional Rider
3+ rides
1
Basic mobility service usage
Regular Rider
25+ rides
0.6
Frequent transportation usage
Power User
75+ rides
0.4
Extensive mobility engagement
Privacy & Security
How ZK Email Protects Your Data
Zero-Knowledge Proofs: ZK Email can verify your purchase patterns without ever seeing your actual emails, personal information, or purchase details.
Zero-knowledge means that it’s mathematically impossible to read the contents of your inbox, not just 'we promise we won't look.' The proof verifies you received an email without revealing its contents—not to Passport, not to anyone.
Similar to how Face ID proves you're you without Apple storing your face, ZK Email proves you received an email without anyone accessing the content.
The Stamp scans for Amazon/Uber emails, generates a cryptographic proof, and that's all ZK Email or Passport receives. The emails themselves never leave your inbox.
As with any Passport Stamp, the ZK Email Stamp is optional, so if you’re still not comfortable with the concept, feel free to prove your humanity with any of our other Stamps.
Data Storage & Retention
No email content stored: Only cryptographic proofs are generated
No personal data retained: Verification results are anonymous
Temporary access only: Permissions can be revoked in your Google account settings
Transparent process: All verification logic is publicly auditable
What ZK Email CAN verify:
That you have Amazon purchase confirmations
That you have Uber ride receipts
The frequency of your activity
What ZK Email CANNOT see:
Your email content or subject lines
Your personal information or addresses
Your purchase amounts or payment details
Your trip destinations or personal data
Full zk proof generation process:
User authorization
The user connects their email account (e.g., Gmail) through OAuth and grants zk.email permission to read specific metadata — not full email contents.
Email retrieval & parsing
zk.email’s off-chain service fetches the relevant email data (headers or structured metadata) and encodes it into a machine-readable format suitable for proving.
Proof generation
A zero-knowledge circuit runs to prove that a valid email meeting predefined conditions exists (e.g., from a specific sender or containing a certain field). The proof hides all personal or message details.
Proof verification
The proof is submitted to a verifier smart contract, which checks its validity. The contract does not learn anything about the underlying email — only that the proof is mathematically sound.
Result anchoring & linking
The verification outcome (a success flag or credential) is anchored on-chain and associated with the user’s wallet. Applications like Human Passport can then read this status to confirm that the user passed verification, without any access to their email or private data.
Learn more: https://docs.zk.email/architecture/zk-proofs
Need Help?
Troubleshooting Steps
See if your Uber/Amazon emails are not in the spam or promotional folder
If yes, move them to the main inbox
Clear the cache and cookies of your browser
Try using another browser
Quick Support Options
Click on the icon in the bottom right corner of this page to reach out to support ↘
When contacting support, include:
Your browser type and version
Error messages or screenshots
Whether you've tried any troubleshooting steps
Your approximate email volume (helps with optimization)
Recommended Next Steps
Complete guide to reaching verification thresholds:
Scoring 20, for humansLast updated
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