Blockchain wallets protect users’ assets by securely storing keys. Research has explored various aspects, including BIP32 for key derivation in cold/hot settings and PDPKS further enhancing key insulation. However, most wallets are either user-managed or exchange-hosted, creating centralized points of failure. Shared-custodial wallets allow users and service providers to collaboratively manage keys, which can lead to potential corruption while still safeguarding asset security. Nonetheless, the need for server involvement in each signature poses challenges to user privacy and efficiency. To address these limitations, we propose NEST, the first efficient wallet that simultaneously satisfies strong key insulation, shared custody and privacy. We restrict malicious users’ access to the server through password-based identity authentication and introduce blindness and unlinkability to prevent malicious servers from associating transactions with specific users. Additionally, we have designed two modes: interactive signing for large transactions with high security requirements, and non-interactive signing for small, high-frequency transactions. Our construction of NEST is based on bilinear pairing and an IND-CCA-secure public key encryption scheme, accompanied by a rigorous security analysis in the random oracle model. We implemented our scheme, and the results demonstrate its practicality.