-1

I have a password and convert it using a online md5 converter and stored it in a file.Now I need the original string . Is it any possible way to decrypt md5 hash value to original using c program. is there any functions in c program.

Durga
  • 319
  • 1
  • 6
  • 18
  • i need to do decryption in c – Durga Jan 19 '15 at 04:14
  • 1
    You want to get a possible infinite length string from a fixed length string representation? – alex Jan 19 '15 at 04:15
  • i have hash of a string and need to convert back to the original. – Durga Jan 19 '15 at 04:17
  • 2
    If it was possible to decrypt hashing functions such as md5 or sha then why would you use it to store a password? Also, hashing is not the same as encrypting. It's one-way. **That's the point.** There's nothing to decrypt because the data is not encrypted. A quick Google search and 5 minutes of research would have answered this question. – Christian Jan 19 '15 at 04:25

1 Answers1

3

It's likely impossible. See here: http://en.wikipedia.org/wiki/MD5

The security of the MD5 hash function is severely compromised. A collision attack exists that can find collisions within seconds on a computer with a 2.6 GHz Pentium 4 processor (complexity of 224.1). Further, there is also a chosen-prefix collision attack that can produce a collision for two inputs with specified prefixes within hours, using off-the-shelf computing hardware (complexity 239). The ability to find collisions has been greatly aided by the use of off-the-shelf GPUs. On an NVIDIA GeForce 8400GS graphics processor, 16–18 million hashes per second can be computed. An NVIDIA GeForce 8800 Ultra can calculate more than 200 million hashes per second.

These hash and collision attacks have been demonstrated in the public in various situations, including colliding document files and digital certificates.

null
  • 161
  • 5