Bitcoin Core v0.6.0 Release
Major update introducing QR codes and BIP 16 (P2SH), enabling multi-signature transactions.
On March 30, 2012, the Bitcoin development team released Bitcoin-Qt version 0.6.0, a substantial upgrade that modernized the user experience and laid the technical rails for advanced transaction types. This release was pivotal for two primary reasons: the introduction of QR code support and the implementation of BIP 16.
For the average user, the most visible change was the integration of QR codes into the receiving address interface. This seemingly simple addition was transformative for peer-to-peer commerce, allowing users to request payments by simply showing a screen, facilitating the first wave of mobile-friendly 'over the counter' trades. Under the hood, however, the critical innovation was the support for BIP 16, also known as Pay-to-Script-Hash (P2SH). This protocol upgrade allowed senders to fund complex transaction scripts (like Multi-Signature wallets) using a standard, fixed-length address format (addresses starting with '3').
P2SH was the solution to the security crisis highlighted by the Linode hack earlier in the month. It enabled the creation of addresses that required multiple private keys to authorize a transaction (e.g., 2-of-3 signatures), massively increasing security for exchanges and businesses. The release also featured a switch to a faster, more robust database structure (LevelDB was in testing, though fully implemented later) to handle the growing blockchain size. Version 0.6.0 represented Bitcoin's transition from a 'hacker's toy' to a system capable of supporting commercial-grade security and usability.