How to embed md5 sum of sentence in the sentence?

Question

For example, how do I solve for x such that md5(“The md5 of this sentence is [x].” = x? Is this possible with a reasonable amount of effort?

Are there any other common cryptographic hashes that make this easier or harder?

I'm voting to close this question as off-topic because of not programming — Thomas M. DuBuisson, Jul 05 '18 at 16:53
Try it yourself with some very short hash functions, say MD5 truncated to only 16 bits. You will see that there is no guarantee that there are any solutions at all. — President James K. Polk, Jul 05 '18 at 23:19

zaph · Accepted Answer · 2018-07-05T19:37:45.170

4

Is this possible with a reasonable amount of effort?

No, at best brute force 2^128, at worst no.

Are there any other common cryptographic hashes that make this easier or harder?

SHA-3 or Skein allow a specified output size with a short output it would be easier. A longer hash output would be harder.

edited Jul 05 '18 at 19:37

answered Jul 05 '18 at 14:11

zaph

1 Answers1