Fixed a heap-corrupting buffer underrun bug in the modmul function
    
      Resolves: CVE-2013-4206
    - Fixed a buffer overflow vulnerability in the calculation of modular
      inverses when verifying a DSA signature
      Resolves: CVE-2013-4207
    - Fixed problem when private keys are left in memory after being
      used by PuTTY tools
      Resolves: CVE-2013-4208