Abstract: At present,a development direction of quantum algorithm is to rethink the early quantum algorithms.Each of them involves an important,groundbreaking concept in quantum computing.They are generally considered to only belong to the theoretical category due to the fact that the problems they solve are of little practical value.However,theyare still important as they can solve a problem exponentially faster than a classical algorithm.Here,this paper elaborates on some recent developments in repurposing the early quantum algorithms for quantum key distribution and other fields.It especially focuses on Deutsch-Jozsa algorithm,Bernstein-Vazirani algorithm and Simon's algorithm.The Deutsch-Jozsa algorithm is used to determine whether a multi-argument function is balanced or constant.As recent research shows,it can be extended to application in the field of quantum communication and formal languages.The Bernstein-Vazirani algorithm finds a string encoded in a function.Its application can be extended to quantum key distribution and error correction.Simon's algorithm tackles the problem of identifying a string with a particular property.Its modern applications include quantum communication and error correction.

Key words: Bernstein-Vazirani algorithm, Deutsch-Jozsa algorithm, Quantum algorithms, Quantum computing, Quantum error correction, Quantum key distribution, Simon's algorithm