From Bitcoin Wiki
This page describes a BIP (Bitcoin Improvement Proposal).
- (24 Feb 2017) Added test vectors for hardened derivation with leading zeros
- (16 Apr 2013) Added private derivation for i ≥ 0x80000000 (less risk of parent private key leakage)
- (30 Apr 2013) Switched from multiplication by IL to addition of IL (faster, easier implementation)
- (25 May 2013) Added test vectors
- (15 Jan 2014) Rename keys with index ≥ 0x80000000 to hardened keys, and add explicit conversion functions.
BIP: 32 Layer: Applications Title: Hierarchical Deterministic Wallets Author: Pieter Wuille <firstname.lastname@example.org> Comments-Summary: No comments yet. Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0032 Status: Final Type: Informational Created: 2012-02-11 License: BSD-2-Clause
The full text of this BIP can be read here.