Statistically, multisignature (multisig) is generally considered the most secure among the three options you mentioned (Single, Shamir, and Multisig). Multisig requires multiple private keys to authorize transactions, making it more resistant to hacking or unauthorized access compared to single key systems. Shamir's Secret Sharing is a cryptographic technique for splitting a secret into multiple parts, and its security depends on the specific implementation and the number of shares required for reconstruction.

In summary:
Single: Least secure, as it relies on a single key, making it vulnerable if that key is compromised.
Shamir: Security depends on the implementation and the number of shares required, but it can be secure if implemented correctly.
Multisig: Generally the most secure, as it requires multiple keys to authorize transactions, reducing the risk of a single point of failure.
However, the actual security of any of these methods depends on various factors, including key management, implementation details, and the strength of the cryptographic algorithms used.