---
title: "Lewis Gilchrist (@lewis-dev) | Hashnode"
description: "Sharing my thoughts regarding the emergent technologies related to Digital Security and Digital Privacy."
url: "https://hashnode.com/@lewis-dev"
---

@lewis-dev

# Lewis Gilchrist

@lewis-dev · London, UK · Joined April 2026

Sharing my thoughts regarding the emergent technologies related to Digital Security and Digital Privacy.

### [The bot problem that CAPTCHA can't solve, and proof of human can](https://devabkk.hashnode.dev/captcha-cant-stop-sybil-attacks-proof-of-human-can?utm_source=hashnode&utm_medium=feed)

reCAPTCHA asks if you look human. Proof of human asks if you're unique. Different questions, different attack surfaces. Here's why it matters.

7 min read · [devabkk.hashnode.dev](https://devabkk.hashnode.dev/captcha-cant-stop-sybil-attacks-proof-of-human-can?utm_source=hashnode&utm_medium=feed)

[Oct 1](https://hashnode.com/posts/captcha-cant-stop-sybil-attacks-proof-of-human-can/6abdeaf5b712493925002e32)

### [How proof of human technology works](https://devabkk.hashnode.dev/how-proof-of-human-technology-works?utm_source=hashnode&utm_medium=feed)

How does proof of human work? A plain, step-by-step look at how it proves you are a real, unique person without revealing who you are.

8 min read · [devabkk.hashnode.dev](https://devabkk.hashnode.dev/how-proof-of-human-technology-works?utm_source=hashnode&utm_medium=feed)

[Sep 17](https://hashnode.com/posts/how-proof-of-human-technology-works/6aabcebb0eae40313565f1f6)

### [The real reason online stores make you verify you're human twice now](https://devabkk.hashnode.dev/the-real-reason-online-stores-make-you-verify-you-re-human-twice-now?utm_source=hashnode&utm_medium=feed)

CAPTCHA fatigue at checkout is real. Here is why e-com verification is increasing, the bot fraud numbers look like, and where merchants are moving.

7 min read · [devabkk.hashnode.dev](https://devabkk.hashnode.dev/the-real-reason-online-stores-make-you-verify-you-re-human-twice-now?utm_source=hashnode&utm_medium=feed)

[Aug 24](https://hashnode.com/posts/the-real-reason-online-stores-make-you-verify-you-re-human-twice-now/6a8c3747722c6cfe29223375)

### [The re-identification problem that breaks "anonymized" data](https://devabkk.hashnode.dev/the-re-identification-problem-that-breaks-anonymized-data?utm_source=hashnode&utm_medium=feed)

Anonymized data is not anonymous. Here is why re-identification works, what k-anonymity guarantees, and the cases that proved it.

7 min read · [devabkk.hashnode.dev](https://devabkk.hashnode.dev/the-re-identification-problem-that-breaks-anonymized-data?utm_source=hashnode&utm_medium=feed)

[Aug 13](https://hashnode.com/posts/the-re-identification-problem-that-breaks-anonymized-data/6a7d90ee87a448b45fc1d14e)

### [Hashing is not the same as anonymizing, and the difference matters](https://devabkk.hashnode.dev/hashing-is-not-the-same-as-anonymizing-and-the-difference-matters?utm_source=hashnode&utm_medium=feed)

Anonymized data is not anonymous. Here is why re-identification works, what k-anonymity guarantees, and the cases that proved it.

8 min read · [devabkk.hashnode.dev](https://devabkk.hashnode.dev/hashing-is-not-the-same-as-anonymizing-and-the-difference-matters?utm_source=hashnode&utm_medium=feed)

[Aug 13](https://hashnode.com/posts/hashing-is-not-the-same-as-anonymizing-and-the-difference-matters/6a7d8bdc2bca71d5b7834e63)