Amazon Interview Question: difference between "hashing a... | Glassdoor

Interview Question

Software Development Engineer Interview Dublin, Co. Dublin (Ireland)

difference between "hashing a string" and "encrypting a

  string". Then: is it possible to find two elements for which the hash is the same?

Interview Answer

3 Answers


you can't "go back" from a hash. You can go back from encription if you know the secret (say password, private key, whatever).
Second question: yes but then you have a problem.

Interview Candidate on Feb 23, 2011

1. Encryption uses a secret key while hashing does not require any key.
Moreover, hash is one-way but encryption can be reversed by a decryption operation.

2. Yes, that's called hash collision, which although a low probability occurrence, does exist.

Neha on Apr 5, 2012

Decryption of encrypted string is possible. But we cannot say same thing for hashing. Because hash is one way operation. Q2:Low probability, it is possible using brute force

Anonymous on Apr 9, 2019

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