# Restriction Enzyme Tool vs PDF File Protector

The clearest difference is price: Restriction Enzyme Tool at Free against PDF File Protector's $19.99. Restriction Enzyme Tool also leads on in-app purchases (none vs 1) and iOS requirement (9.0 vs 16.6). PDF File Protector's advantage is update cadence (every 2 months vs every 8 months). On ads and device support there is nothing between them.

Restriction Enzyme Tool is free to download; PDF File Protector costs $19.99 up front. PDF File Protector sells 1 one-off in-app purchase. Restriction Enzyme Tool asks for nothing beyond the download.

Restriction Enzyme Tool ships an update every 8 months, PDF File Protector every 2 months. The most recent releases landed on October 4, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | Restriction Enzyme Tool | PDF File Protector |
| --- | --- | --- |
| Price | **Free** | $19.99 |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 8 months | **Every 2 months** |
| Size | 9 MB | 7 MB |
| Requires iOS | **9.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Promega Corporation](https://appshunter.io/developer/307546952) | [乐祥 胡](https://appshunter.io/developer/1572365721) |

## What reviewers say

### Restriction Enzyme Tool

[App page](https://appshunter.io/ios/app/restriction-enzyme-tool/id1000803979)

**In-app purchases:** none


### PDF File Protector

[App page](https://appshunter.io/ios/app/pdf-file-protector/id6738285744)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| pdf签名内购 | $9.99 | one-time |


## Frequently asked questions

### Is Restriction Enzyme Tool free?

Restriction Enzyme Tool is free to download, with no in-app purchases.

### Is PDF File Protector free?

PDF File Protector costs $19.99, and also offers in-app purchases.

### Do Restriction Enzyme Tool or PDF File Protector have ads?

Neither Restriction Enzyme Tool nor PDF File Protector shows ads.

### Which is updated more often, Restriction Enzyme Tool or PDF File Protector?

Restriction Enzyme Tool ships an update every 8 months, and PDF File Protector every 2 months. Most recently, Restriction Enzyme Tool was updated on October 4, 2026 and PDF File Protector on September 26, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*