Bitcoin developers proposed BIP-361 to combat potential future quantum attack risks

One of the btc-42">Bitcoin contributors, Jameson Loop, along with other cryptographers, has proposed an initiative that may force Bitcoin holders to migrate their tokens to new quantum-resistant addresses, or else their tokens will be permanently frozen by the network itself. In this scenario, holders technically still own these coins but will lose the ability to transfer them. This is known as Bitcoin Improvement Proposal BIP-361, which was updated on Tuesday in Bitcoin's official proposal repository, titled "Post-Quantum Migration and Old Signature Retirement."

BIP-361 builds on the BIP-360 proposal introduced in February. BIP-360 introduced a soft fork (a type of network upgrade) aimed at enabling a new transaction type called "Pay to Merkle Root" (P2MR). This approach draws on Bitcoin's Taproot (P2TR) framework but removes key-based spending paths, thereby eliminating an element widely considered to pose risks in the quantum era.

The BIP-361 proposal divides the migration into three phases. Phase A starts three years after activation and prohibits anyone from sending new bitcoins to old, quantum-vulnerable addresses. You can still spend from these addresses, but you cannot receive any coins. Phase B starts five years after activation and will render old signatures (ECDSA and Schnorr) completely ineffective, with the network rejecting any attempts to spend coins from quantum-vulnerable wallets.

Essentially, your coins will be frozen. Finally, there is Phase C, which is a rescue plan still under research: holders of frozen wallets may potentially prove ownership through zero-knowledge proofs (a method of proving knowledge of a secret without revealing the secret itself). If successful, the coins frozen in Phase B can be recovered.