Chaum Blind Signatures

Implementation using RSA.

• Blinding.

  • Random blinding factor $K$.

  • $k * k^{-1} \equiv 1 (modn)$

  • $m' = k^e * m mod N$

• Ordinary signature (encryption w/ private key).

  • $A_x(m') = (m')^d modN$

• Unblinding

  • $A_x(m) = k^{-1}*A_x(m')mod$