Re: Quantum Cryptography can not work

Entanglement has been experimentally observed.

A (simplified) description can be given. Single particle states are
represented by a matrix (say 2x2). Two particle states are represented
by a (Kronecker) product of two matrices (these are 4x4). There are
4x4 matrices that are not such Kronecker products but still represent
two particles. The lack of a factorization means that the two
particles are entangled.

.