<p>Internet of Things security and privacy concerns are being addressed with blockchain technology, which is still in its development. The blockchain technology uses the cryptography hash algorithm with signature scheme to transact the information securely. The attention of attackers was increased in existing signature schemes due to the usage of small 128 bytes input key size. In addition, it increases security attacks such as ‘brute force attack’ and ‘sybil attack’. So, the researcher needs to concentrate on increasing the key size for avoiding the vulnerabilities. At the same time, increasing the key size leads to improper transaction with less accuracy, less throughput with increased time. So, this work concentrates on to propose a new key added signature scheme based on hash (NKAS) to increase the key entropy up to 256 bytes to increase the difficulty of security attacks. Additionally, the scheme identifies another shortest path between node to pass the message, when the sybil and brute force attack present. Then, the proposed signature scheme is analyzed with different cryptography hash functions like ‘SHA224’, ‘SHA256’, ‘SHA384’, ‘SHA512’, ‘MD5’, ‘SHA3-224’, ‘SHA3-256’, ‘SHA3-384’, ‘SHA3-512’, and ‘ECC’ in terms of accuracy, signature size, throughput, and time complexity. From this analysis, the NKAS scheme with ECDSA generates the 128 bytes of hash for 256 bytes of input key with accuracy of 82.6%, logarithmic time consumption of 1.68&#xa0;ns and throughput of 15.24&#xa0;KB per 200&#xa0;ns.</p>