The U.S. Department of Defense's blockchain supply chain pilot projects aim to enhance transparency and security but face data tampering risks. Blockchain's immutable ledger reduces tampering by ensuring data integrity through cryptographic signatures and decentralized consensus. However, vulnerabilities persist if private keys are compromised or if malicious actors infiltrate the network. Pilot programs, like those by SIMBA Chain, use permissioned blockchains to limit access, but insider threats or flawed smart contracts could enable tampering. The DoD must enforce robust access controls, regular audits, and secure key management to mitigate risks. While blockchain strengthens supply chain auditability, its effectiveness depends on rigorous implementation and continuous monitoring to prevent unauthorized data alterations, ensuring trust in critical defense logistics.