tss

https://github.com/grempe/tss-rb

Threshold Secret Sharing (TSS) provides a way to generate N shares from a value, so that any M of those shares can be used to reconstruct the original value, but any M-1 shares provide no information about that value. This method can provide shared access control on key material and other secrets that must be strongly protected. This gem implements a Threshold Secret Sharing method based on polynomial interpolation in GF(256) and a format for the storage and transmission of shares. This implementation follows the specification in the document: http://tools.ietf.org/html/draft-mcgrew-tss-03