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Overview

Kayston’s Forge provides a complete suite of encoding and cryptographic tools that run entirely in your browser. All processing is client-side, ensuring your sensitive data never leaves your machine.

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Available Tools

Unix Time Converter

Convert between Unix timestamps (seconds/milliseconds) and human-readable dates. Displays local time, UTC, ISO format, and relative time.

Base64 String Encode/Decode

Encode UTF-8 text to Base64 or decode Base64 strings back to text. Supports URL-safe Base64 encoding.

Base64 Image Encode/Decode

Convert images to Base64 data URLs or decode Base64 back to image content. Preview images inline.

JWT Debugger

Inspect JSON Web Token headers and payloads without sending data to external servers. Shows claims, expiration time, and decoded structure.

URL Encode/Decode

Encode and decode URL components. Supports standard URL encoding, component encoding, and form encoding.

URL Parser

Break down URLs into protocol, hostname, port, pathname, query parameters, and hash fragments.

Cron Job Parser

Parse cron expressions into human-readable descriptions and preview the next 5 scheduled runs.

Certificate Decoder

Decode and inspect X.509 certificates (SSL/TLS). Supports PEM and DER formats. View subject, issuer, validity period, and more.

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Base64 String Encoding

The Base64 String tool supports three encoding modes: Standard Base64 
Input:  Hello, World!
Output: SGVsbG8sIFdvcmxkIQ==
URL-Safe Base64 (no padding, uses - and _ instead of + and /) 
Input:  Hello, World!
Output: SGVsbG8sIFdvcmxkIQ
Decode 
Input:  SGVsbG8sIFdvcmxkIQ==
Output: Hello, World!
The decoder automatically handles both standard and URL-safe Base64, including missing padding.

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JWT Debugging

The JWT Debugger decodes JSON Web Tokens and displays:
  • Header: Algorithm and token type
  • Payload: Claims including sub, iat, exp, custom claims
  • Expiration Status: Shows if the token is expired
Example Output 
// Header
{
  "alg": "HS256",
  "typ": "JWT"
}

// Payload
{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022,
  "exp": 1735689600
}

// Expires At: 2025-01-01T00:00:00.000Z
// Expired: false
The JWT Debugger does not verify signatures. It only decodes the header and payload. Never trust JWT claims without signature verification.

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Hash Generation

The Hash Generator supports multiple algorithms:
  • MD5 (128-bit, insecure for cryptographic use)
  • SHA-1 (160-bit, deprecated for security)
  • SHA-256 (256-bit, recommended)
  • SHA-512 (512-bit, maximum security)
  • HMAC-SHA256 (keyed hash for message authentication)
Example: SHA-256 Hash 
Input:  hello world
Output: b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
The tool also displays Base64 and Base64URL encodings of the hash.
For password hashing, use dedicated key derivation functions like bcrypt, scrypt, or Argon2. Do not use plain SHA-256 for passwords.

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URL Encoding

Supports three encoding modes: URI Encoding - Encodes all characters except unreserved characters 
Input:  https://example.com/path?q=hello world
Output: https://example.com/path?q=hello%20world
Component Encoding - Encodes more aggressively, suitable for query parameters 
Input:  key=value&special=@#$
Output: key%3Dvalue%26special%3D%40%23%24
Form Encoding - Uses + for spaces instead of %20 
Input:  hello world
Output: hello+world

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Unix Time Conversion

The Unix Time Converter automatically detects whether your input is:
  • Seconds (10 digits or less)
  • Milliseconds (more than 10 digits)
  • ISO 8601 date string
  • Human-readable date
Example Output 
Local: 1/1/2025, 12:00:00 AM
UTC: Wed, 01 Jan 2025 00:00:00 GMT
ISO: 2025-01-01T00:00:00.000Z
Relative: in 10 months
Unix Seconds: 1735689600
Unix Milliseconds: 1735689600000

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Cron Expression Parsing

The Cron Parser translates cron expressions into plain English and shows upcoming execution times. Example 
Input:  0 9 * * 1-5
Output: At 09:00 AM, Monday through Friday

Next runs:
- Monday, March 10, 2026, 9:00:00 AM
- Tuesday, March 11, 2026, 9:00:00 AM
- Wednesday, March 12, 2026, 9:00:00 AM
- Thursday, March 13, 2026, 9:00:00 AM
- Friday, March 14, 2026, 9:00:00 AM

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Certificate Decoder

The Certificate Decoder parses X.509 certificates using a pure JavaScript ASN.1 DER parser. It supports:
  • PEM format (Base64-encoded with -----BEGIN CERTIFICATE----- headers)
  • DER format (binary)
Displays:
  • Subject (CN, O, OU, C)
  • Issuer (certificate authority)
  • Validity period (Not Before / Not After)
  • Serial number
  • Signature algorithm
  • Public key algorithm and modulus
This tool is for inspection only. It does not verify certificate chains or validate signatures against a trust store.

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Privacy & Security

All encoding and hashing operations run entirely in your browser using native Web Crypto APIs and battle-tested JavaScript libraries.
No data is transmitted to external servers. Your JWT tokens, certificates, and sensitive data remain on your machine.
The app runs as a fully static site with no backend. Even the hosting provider cannot intercept your data.

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Best Practices

Base64 is Encoding, Not Encryption Base64 is a data encoding format, not a security mechanism. Anyone can decode Base64 strings. Never use Base64 to “hide” passwords or secrets. Use Strong Hash Functions
  • For general integrity checks: SHA-256 or SHA-512
  • For password storage: bcrypt, scrypt, or Argon2 (not available in browser)
  • For message authentication: HMAC-SHA256 with a secret key
Validate JWT Signatures The JWT Debugger only decodes tokens. In production applications, always verify the signature using the appropriate algorithm and secret/public key. Certificate Validation Inspecting a certificate’s fields does not validate trust. Real certificate validation requires checking:
  • Signature chain up to a trusted root CA
  • Revocation status (OCSP or CRL)
  • Hostname matching
  • Validity period

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Keyboard Shortcuts

  • Cmd/Ctrl + Enter - Execute the current tool action
  • Cmd/Ctrl + Shift + C - Copy output to clipboard
  • Cmd/Ctrl + K - Open command palette to switch tools