(k, n) secret base64 data sharing scheme using simple modular arithmetic

A (k, n) secret sharing (SS) is a threshold scheme that shares secret multimedia data into n sub-secrets (called shares). When any k or more shares are collected, the secret is recovered. And any (k − 1) or fewer shares have no information about the secret. The original purpose of SS is to protect the keys in the cryptographic system. Today it has expanded to many application areas. When we want to share secret multimedia data over SS in a distributed network, transmitting the multimedia in raw data format is not appropriate because control characters may break some protocols (e.g., email and HTML). We pioneer to study secret Base64 data sharing (SBS) to avoid disruption. Extending SS to SBS is not an easy task. Using Base64 data instead of the original data as the secret data presents the following challenges: (i) Base64 data is not as error-tolerant as images, so modular arithmetic must be carefully designed; (ii) Our SBS also uses all polynomial coefficients to share the Base64 data, so the Base64 data must be permuted before sharing. We need to devise a method that allows k participants in the recovery to share a permutation key. In the proposed (k, n)-SBS, we study the use of modular operations on lossless secret multimedia to achieve lower computational complexity and smaller share size.