Very short digital signature RRS feed

  • Question

  • Hi,

    I am looking for any information on short digital signatures. RSA and DSA signatures are too long for the purpose I want to use them. I would like to generate signatures that are 80 bits or perhaps 128 bits in length. At the moment I am willing to sacrifice security for size. 

    Could anyone recommend a digital signature algorithm that would produce such short signatures? If possible, could you also point me to an implementation (C, C++, C#)? 

    Thank you!
    Monday, January 12, 2009 10:16 AM

All replies

  • If you're willing to sacrifice security, use RSA with shorter N values. But 128 bits of RSA will be broken really easily on a home PC.
    Another chance is to make up your own (probably insecure) algorithm, hoping that your product won't seem important enough for crackers to bother with the maths since they won't be able to crack it with standard tools.
    Sunday, July 12, 2009 10:48 AM
  • Maybe you could try the elliptic curve cryptography, but you have to grow a little in sizes: keys start from around 380 bit. You can easily find some implementation on sourceforge (I've used this library and works fine: http://sourceforge.net/projects/libecc/)
    Tuesday, August 4, 2009 10:03 AM