We present a comprehensive and universal quantum computing model based on 2-qubit measurements (TQC), which embeds trivially in a model based on 1-qubit measurements known as the one-way model (1WQC). One inherits through this embedding a calculus whereby each TQC computing pattern can be put in a standard form where entanglement is done first, then measurement, then local corrections.

Many of the popular Merkle-Damg̊ard hash functions have turned out to be not collision-resistant (CR). The problem is that we no longer know if these hash functions are even second-preimage-resistant (SPR) or one-way (OW), without the underlying compression functions being CR. We remedy this situation by introducing the “split padding” into a current Merkle-Damg̊ard hash function H. The patched h...

MD2 is an early hash function developed by Ron Rivest for RSA Security, that produces message digests of 128 bits. In this paper, we show that MD2 does not reach the ideal security level of 2. We describe preimage attacks against the underlying compression function, the best of which has complexity of 2. As a result, the full MD2 hash can be attacked in preimage with complexity of 2.