cbip32

A fast, secure, low-dependency implementation of BIP32

• Depends only on libsecp256k1 and libsodium (for SHA256, HMAC-SHA512, and context randomization)
• No heap allocations (aside from secp context), which allows end users to manage memory securely
• Implemented in pure C for ease of FFI
• Extensively tested
  • Uses cross-implementation fuzz testing against python-bip32 and verystable.

Installation from source

Install libsecp256k1

git clone https://github.com/bitcoin-core/secp256k1.git && \
  cd secp256k1 && ./autogen.sh && ./configure && make && sudo make install

# NOTE: in production, you should verify the associated GPG sigs and/or pin hashes.

Install libsodium

git clone https://github.com/jedisct1/libsodium.git && \
  cd libsodium && ./autogen.sh -sb && ./configure && make && sudo make install

# NOTE: in production, you should verify the associated GPG sigs and/or pin hashes.

Install this library

git clone https://github.com/jamesob/cbip32.git && \
  make && sudo make install

Tests

• Vectors from BIP32
• Cross-implementation fuzz
• C unittests
• C fuzz

Performance

The Python bindings for this implementation have been shown to be

• ~2x faster than python-bip32, an implementation based on coincurve which itself wraps libsecp256k1
• >100x faster than verystable, which is a "dumb" pure Python implementation.

From fuzzing:

  - Highest target scores [time per derivation]:
     0.0162932  (label='ours')
     0.0379755  (label='python-bip32')

  - Highest target scores [time per derivation]:
     0.00222896  (label='ours')
     0.315636    (label='verystable')

Example bindings included

Python (./examples/py)

>>> from bindings import derive
>>> derive('0' * 32, 'm/1/2h').get_public().serialize()
'xpub69s9RVsS4kfK2VFed2giqFm9gQ4VmCWuWcPHFJ51Rj6dHvBjCicCZm2HR88Z6J5zRYyHkt7W9LPygBc57RCCPp2t1AxCNa1VtvSq4qWYLqK'

Go (./examples/go)

package cbip32

// #cgo CFLAGS: -I.
// #cgo LDFLAGS: -lbip32
// #include "bip32.h"
import "C"
import (
    "unsafe"
)

type BIP32Key struct {
    cKey C.bip32_key
}

func NewKey() *BIP32Key {
    key := &BIP32Key{}
    C.bip32_init(&key.cKey)
    return key
}

func Derive(source, path string) (*BIP32Key, bool) {
    key := NewKey()
    cSource := C.CString(source)
    cPath := C.CString(path)
    defer C.free(unsafe.Pointer(cSource))
    defer C.free(unsafe.Pointer(cPath))

    result := C.bip32_derive(&key.cKey, cSource, cPath)
    return key, result == 1
}