feat: add bech32 bech32m

[thomasxm]

Summary

Adds Bech32 and Bech32m encoding/decoding operations as specified in BIP-0173 and BIP-0350. These encodings are widely used for Bitcoin SegWit/Taproot addresses, Lightning Network invoices, Nostr keys, and other cryptocurrency applications.

New Operations

• To Bech32 - Encodes data to Bech32 or Bech32m format with configurable HRP
• From Bech32 - Decodes Bech32/Bech32m strings with auto-detection support

Features

• Configurable Human-Readable Part (HRP) for different use cases
• Support for both Bech32 (BIP-0173) and Bech32m (BIP-0350)
• Auto-detect mode tries Bech32 first, then Bech32m
• Bitcoin SegWit mode for proper witness version handling
• Multiple output formats: Hex, Raw, Bitcoin scriptPubKey, HRP: Hex, JSON
• Magic auto-detection patterns for Bitcoin/Litecoin/AGE addresses
• Comprehensive error messages for invalid input

Use Cases

• Bitcoin SegWit addresses (bc1q...)
• Bitcoin Taproot addresses (bc1p...)
• Lightning Network payment requests
• Nostr public/private keys (npub/nsec)
• Litecoin addresses (ltc1...)
• AGE encryption keys

Technical Details

• Pure JavaScript implementation (no external dependencies)
• Algorithm verified against official BIP reference implementations
• Maximum output length enforced at 90 characters per specification
• Validates HRP characters (ASCII 33-126)
• Mixed case detection and rejection per BIP specification
• Proper SegWit witness version handling (v0-v16)
• Correct padding validation per BIP-0173 convertbits specification

Files Changed

• src/core/lib/Bech32.mjs - NEW - Core Bech32/Bech32m library implementation
• src/core/operations/ToBech32.mjs - NEW - Encode operation
• src/core/operations/FromBech32.mjs - NEW - Decode operation
• src/core/config/Categories.json - Added operations to Data format category
• tests/operations/tests/Bech32.mjs - NEW - Test suite (60 test cases)
• tests/operations/index.mjs - Registered test module

Testing

• All 1776 tests pass
• BIP-0173 and BIP-0350 official test vectors included
• Bitcoin mainnet/testnet address round-trip tests
• SegWit witness program validation tests
• scriptPubKey output format verification
• Error handling tests for invalid inputs
• Verified against real-world Bitcoin addresses

Test Vectors

Includes official test vectors from:

• BIP-0173 (Bech32 for SegWit v0)
• BIP-0350 (Bech32m for SegWit v1+)

Test 1: Bitcoin Mainnet SegWit v0 (P2WPKH)

• Input: BC1QW508D6QEJXTDG4Y5R3ZARVARY0C5XW7KV8F3T4
• Output (Bitcoin scriptPubKey): 0014751e76e8199196d454941c45d1b3a323f1433bd6

Test 2: Bitcoin Testnet SegWit v0 (P2WSH)

• Input: tb1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3q0sl5k7
• Output (Bitcoin scriptPubKey): 00201863143c14c5166804bd19203356da136c985678cd4d27a1b8c6329604903262

Test 3: Witness v1 (64-byte program)

• Input: bc1pw508d6qejxtdg4y5r3zarvary0c5xw7kw508d6qejxtdg4y5r3zarvary0c5xw7k7grplx
• Output (Bitcoin scriptPubKey): 5128751e76e8199196d454941c45d1b3a323f1433bd6751e76e8199196d454941c45d1b3a323f1433bd6

https://slowli.github.io/bech32-buffer/

References

• BIP-0173: Bech32
• BIP-0350: Bech32m
• BIP-0141: SegWit
• NIP-19: Nostr bech32 entities
• Bech32 Wikipedia

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