Bitcoin Ground Control — Offline Crypto Toolkit

Hash Functions

SHA-1, SHA-256, and SHA-512 computed with the browser’s own Web Crypto implementation (crypto.subtle.digest). No JavaScript hash code is involved in this module.

Algorithm

Input source

Input text

0 characters. Encoded as UTF-8 before hashing.

Hex digest

—

Base64 digest

—

Input bytes: —
Output bytes: —
Elapsed: —

HMAC

Keyed message authentication using crypto.subtle.importKey and crypto.subtle.sign. Both key and message may be supplied as text or as hex bytes.

Algorithm

Key Key is hex bytes

The key must be non-empty.

Message Message is hex bytes

MAC (hex)

—

MAC (Base64)

—

Key bytes: —
Message bytes: —
MAC bytes: —
Elapsed: —

AES-GCM Encrypt / Decrypt

PBKDF2-SHA-256 with 600,000 iterations (OWASP 2023 guidance), a fresh 16-byte salt, and AES-GCM 256-bit with a 12-byte IV and a 128-bit authentication tag. All primitives come from Web Crypto.

The password is never logged, echoed, stored, or transmitted. It lives only in this input field and in memory for the duration of the operation. A wrong password or a corrupted payload produces an explicit authentication failure — never partial plaintext.

Encrypt

Password

Entropy estimate: —

Plaintext

Payload — v1:Base64(salt ‖ iv ‖ ciphertext ‖ tag)

—

Salt (hex): —
IV (hex): —
Ciphertext+tag: —

Decrypt

Password

Payload (Base64, with v1: prefix)

Recovered plaintext

—

Salt (hex): —
IV (hex): —

Base64 Encode / Decode

Standard Base64 (RFC 4648 §4) and URL-safe Base64 (RFC 4648 §5). Decoding is strict: invalid characters and malformed padding are rejected with a specific message rather than silently skipped.

Mode

Alphabet

Input

0 characters.

Base64 output

—

Input bytes: —
Output bytes: —

Base58 / Base58Check

Bitcoin alphabet, BigInt-based base conversion, and double-SHA-256 checksums. Leading 0x00 bytes are preserved as leading 1 characters, and the alphabet deliberately excludes 0, O, I, and l.

Base58 encode — raw bytes → string

Input bytes (hex)

Whitespace and a leading 0x are ignored. Byte length: 0.

Base58

—

Base58 decode — string → raw bytes

Base58 string

Decoded bytes (hex)

—

Byte length: —
Leading zero bytes: —

Base58Check encode — version ‖ data → address

Version byte preset

Version byte(s) (hex)

Payload (hex)

Base58Check

—

Version ‖ data: —
SHA-256(SHA-256(...)): —
Checksum (first 4 bytes): —
Payload ‖ checksum: —
Base58Check result: —

Base58Check decode — with audit trail

Base58Check string

Version length (bytes)

Use 4 for BIP32 xprv / xpub strings.

Decoded bytes (hex): —
Payload (version ‖ data): —
SHA-256(SHA-256(payload)): —
Expected checksum: —
Provided checksum: —
Checksum verdict: —
Version byte(s): —
Data: —

WIF helper — private key → Wallet Import Format

Private key (32 bytes, hex)

Network / version byte

Compressed WIF (0x01 suffix appended)

—

Uncompressed WIF

—

Decode a WIF back to a private key

Network: —
Compression flag: —
Private key (hex): —
Checksum: —

Address helper — hash160 or public key → P2PKH address

Input type

Version byte (hex)

Input (hex)

Hash path: —
hash160: —
Address: —

RIPEMD-160 (pure JavaScript)

Web Crypto does not expose RIPEMD-160, so this toolkit ships a compact, readable pure-JavaScript implementation. It is the only primitive here that is not provided by the browser.

This implementation has not been constant-time audited. Use it for verification, teaching, and test-vector checking — not for handling live private keys. The P2PKH address helper uses it; treat those addresses as verification output.

Input encoding

Input

RIPEMD-160 digest (hex, 20 bytes)

—

Known-answer test vectors
Input	Expected digest	Computed	Result

Bitcoin Address Inspector

Read-only Base58Check decode. Paste a Bitcoin address or a WIF private key and the toolkit reports the version byte, network, type, payload, and checksum verdict. Input is never stored, never transmitted, and is discarded when you clear the field or reload the page.

Address or WIF

Checksum: —
Version byte: —
Network: —
Type: —
Payload (hex): —
Payload length: —
Notes: —