经典密码学和量子密码学之间的差异

经典密码学：经典密码学基于数学，它依赖于分解大数的计算难度。经典密码学的安全性是基于大数实例分解的数学问题的高度复杂性。

量子密码学：量子密码学基于物理学，它依赖于量子力学定律。正在兴起的技术强调量子物理学现象，在这种现象中，两方可以基于量子力学定律的不变性进行安全通信。

古典与经典的比较。量子密码学：

Classical Cryptography	Quantum Cryptography
It is based on mathematical computation.	It is based on quantum mechanics.
It is widely used.	It is sophisticated.
Digital signature is present.	Digital signature is absent.
Bit rate depends on computational power.	Average bit rate is 1 MBPS.
Bit storage 2n n-bit strings.	Bit storage one n-bit string.
Communication range is millions of miles.	Communication range is maximum 10 miles.
Deployed and tested.	In initial stages, not tested fully.
Required up gradation as computing power increases.	It is based in physics laws.
Communication medium independent.	Communication medium dependent.
Expenditure is very less.	Expenditure is high.