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2 votes

How to generate an arbitrary file matching a given MD5 hash?

In general, no. For MD5, we know a cheap way of finding collisions, i.e. finding two files F1 and F2 such that F1≠F2 MD5(F1) = MD5(F2). Even better, we know how to find collisions with a known prefix: ...
Gilles 'SO- stop being evil''s user avatar
1 vote

What are the chances of two 5-symbol strings derived from md5 colliding?

The number of possible truncated hashes is $d=16^5$. Assuming MD5 is perfectly random, by the birthday bound, your probability of seeing at least one collision is approximately $$ 1 - \left(\frac{d-1}{...
rozbb's user avatar
  • 430
1 vote

Is it safe to sign a short token with salted md5

What you're referring to is a message authentication code, or MAC. In general, you should avoid using Merkle-Dåmgard hash functions (such as MD5, SHA-1, or SHA-2) with a salt or key as a MAC because ...
bk2204's user avatar
  • 3,476

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