Kestrel Cipher is currently in development. Features shown may change before release.

macOS · In Development

Kestrel Cipher

Cryptography & Encoding Toolkit

11 professional security tools in one native macOS app. Hash, encode, decode, analyze passwords, inspect certificates, compute subnets, and view hex dumps — all 100% offline with zero network connections.

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100% offline. App Sandbox enabled. No data leaves your device.
KestrelCIPHER
Cryptography
Hashing
Encoding/Decoding
JWT Decoder
Security
Certificate Viewer
Password Analyzer
Utilities
Regex Tester
String Diff
UUID Generator
Network
IP/Subnet Calculator
Timestamp Converter
Data
Hex Viewer
100% Offline
No Network Connections

Hashing

MD5, SHA-1, SHA-256, SHA-512 of text or dropped files
Input Text
# Hash
Clear
MD5
SHA-1
SHA-256
SHA-512

11 Tools. One App. Zero Connections.

Every tool runs entirely on your device. No cloud processing, no API calls, no telemetry.

Cryptography

Hashing

Compute MD5, SHA-1, SHA-256, and SHA-512 digests from text input or drag-and-drop files.

Encoding / Decoding

Convert between Base64, URL Encode, HTML Entities, Hexadecimal, Binary, and ASCII. Chain conversions with the swap button.

JWT Decoder

Decode header, payload, and signature from any JSON Web Token. Auto-detects expiration status.

Security

Certificate Viewer

Inspect PEM-encoded X.509 certificates. Extract subject, issuer, validity, algorithm, and expiration status.

Password Analyzer

Real-time entropy calculation, strength scoring, pattern detection, and crack time estimation. Zero data leaves the device.

Utilities

Regex Tester

Build and test regular expressions with flag toggles. See all matches with byte ranges and capture groups.

String Diff

Side-by-side text comparison with color-coded output. Added, removed, changed, and unchanged lines.

UUID Generator

Bulk generate v4 UUIDs (1 to 1,000). Options for uppercase, lowercase, with or without dashes.

Network

IP / Subnet Calculator

Enter any IPv4 CIDR to compute subnet mask, network address, broadcast, usable hosts, IP class, and RFC 1918 detection.

Timestamp Converter

Live clock with bidirectional epoch/date conversion. Auto-detects seconds vs milliseconds. Multiple timezone support.

Data

Hex Viewer

Drag-and-drop file hex dump with color-coded bytes. Detects 16+ file signatures. Hex search with highlighting. Capped at 64KB.

Platform

macOS 14.0 (Sonoma) or later. Built with SwiftUI, CryptoKit, and CommonCrypto. App Sandbox enabled.

Privacy

Zero network connections. No telemetry. No data leaves the device. File access is limited to user-selected drag-and-drop (read-only).

Part of the Kestrel Suite

Kestrel Cipher joins Kestrel Sight and Kestrel Lite (iOS/iPadOS PCAP analysis) and Kestrel Talon (macOS PCAP analysis) as part of the Kestrel family. All apps share the same dark theme, offline-first philosophy, and zero-telemetry commitment.