Peter Todd (Canada) is a cryptographer, applied cryptography consultant, and Bitcoin Core developer. He graduated from OCAD University (Ontario College of Art and Design) in 2011 with a degree in Integrated Media, and previously worked as an analog electronics designer at geophysics startup Gedex Inc. He registered a GitHub account in April 2008. He is known for his focus on Bitcoin protocol security, scalability, and his outspoken views on technical trade-offs.
BitcoinTalk and Satoshi: Todd registered on BitcoinTalk on December 7, 2010 under the username “retep.” At the time, few noticed that the handle was Peter spelled backwards — Bitcoin Core developer Gregory Maxwell commented in October 2024 on Hacker News that “it took me nearly a decade to realize retep was peter backwards.” Years later, Todd changed the account’s username to “Peter Todd.” Three days after registration, on December 10, he replied to a Satoshi Nakamoto post in the “Fees in BitDNS confusion” thread, where Satoshi had described a concept for transaction replacement — what would later become known as Replace-by-Fee. This was only Todd’s second post on the forum. Satoshi’s last public post came two days later, on December 12, 2010.
Bitcoin Core Contributions: Todd became an active Bitcoin Core contributor starting in April 2012, eventually becoming the 11th most prolific contributor to Bitcoin Core’s GitHub repository. He focused on protocol-level security, transaction policy, and network resilience.
BIP 65: OP_CHECKLOCKTIMEVERIFY (October 2014): Todd proposed BIP 65, introducing a new opcode that allows transaction outputs to remain unspendable until a specified future time. Deployed as a soft fork, it became a building block for payment channels and the Lightning Network.
Replace-by-Fee (RBF) — BIP 125 (December 2015): Todd is best known for championing Replace-by-Fee (RBF), which allows unconfirmed transactions to be replaced by new versions with higher fees. The concept was formalized in BIP 125, co-authored by David A. Harding and Peter Todd. The BIP’s rationale explicitly traces the concept back to Satoshi Nakamoto’s original transaction replacement mechanism.
OpenTimestamps (September 2016): Todd created OpenTimestamps, an open-source project that uses the Bitcoin blockchain to create tamper-proof timestamps, allowing anyone to prove that a document existed at a particular point in time. The project generalizes the timestamping function that Satoshi built into Bitcoin’s core design.
Zcash Trusted Setup Ceremony (October 2016): Todd was one of six participants in the Zcash trusted setup ceremony. He conducted his computation while driving across British Columbia, shielded his laptop in a Faraday cage, and destroyed the hardware with a propane torch. Despite participating, he was deeply critical of the process, stating that collusion among participants was unprovable and the unaudited deterministic builds made the ceremony “crypto hocus pocus.”
Other Roles: Todd served as Chief Scientist at Mastercoin and Dark Wallet, and contributed to the design of stealth addresses (BIP 63, unimplemented) for enhanced privacy. He worked as a consultant at Coinkite starting July 2014.
HBO Documentary (October 2024): In October 2024, the HBO documentary “Money Electric: The Bitcoin Mystery” named Todd as a candidate for Satoshi Nakamoto’s true identity, pointing to his December 2010 reply to Satoshi’s post as evidence. Todd denied the claim, calling it irresponsible and dangerous.
8 entries
Peter Todd's very first post on BitcoinTalk, made one minute after registering under the username 'retep.' A single sentence offering to buy a Diaspora social network invite for $2 — notably in USD, not BTC, unlike other buyers in the thread who offered 0.5–2 BTC. Three days later, his second post would be a technical reply to Satoshi Nakamoto's description of transaction replacement.
Satoshi Nakamoto describes a possible design for transaction replacement — allowing a double-spend with a higher fee to replace the original transaction. This concept would later become known as Replace-by-Fee (RBF). Peter Todd replied to this post approximately 1.5 hours later.
Peter Todd proposed BIP 65, introducing the OP_CHECKLOCKTIMEVERIFY opcode that allows Bitcoin transaction outputs to remain unspendable until a specified future time. The proposal redefined the existing NOP2 opcode and was deployed as a soft fork, enabling use cases including escrow with delayed access, two-factor wallets, and payment channels.
Defined a signaling mechanism for opt-in Replace-by-Fee (RBF), allowing unconfirmed transactions to be replaced by new versions with higher fees. RBF improved fee estimation and market efficiency but was controversial for its impact on zero-confirmation transaction security.
BIP 125 formalized opt-in Replace-by-Fee (RBF), allowing Bitcoin transaction senders to signal that their unconfirmed transactions may be replaced by higher-fee versions. The concept traces directly to Satoshi Nakamoto's original transaction replacement mechanism described on BitcoinTalk in December 2010 — the same thread where Peter Todd made his second-ever forum post.
Peter Todd announced OpenTimestamps, an open-source infrastructure for creating cryptographic timestamps using the Bitcoin blockchain. The system can timestamp an unlimited number of documents in a single Bitcoin transaction through Merkle tree aggregation, providing free, scalable, trust-minimized proof that data existed at a specific point in time.
Peter Todd participated as one of six individuals in the Zcash trusted setup ceremony in October 2016, then published a detailed account criticizing the process. He conducted his computation while driving across British Columbia, shielded his laptop in a Faraday cage, and destroyed the hardware with a propane torch afterward — yet concluded the ceremony was fundamentally flawed because the deterministic builds were unaudited and collusion was unprovable.
HBO documentary 'Money Electric: The Bitcoin Mystery,' directed by Cullen Hoback, names Peter Todd as a Satoshi Nakamoto candidate. The film's central evidence was a 2010 BitcoinTalk forum post where Todd replied to Satoshi's description of Replace-by-Fee, and Todd's later formalization of RBF in BIP 125. Todd denied the claim, calling it 'ludicrous.' The documentary was widely criticized by the Bitcoin community.