sdlh - compute and print SDLH message digest of files


sdlh [-256] [-slow] [-key keyfile] files


Print the hash value computed on the string stored in a file. The message string is converted into a long integer x as in PKCS#1-OS2IP processing the characters in the reverse order.

hash(x) = g^x mod n

The length of the hash value will depend on the modulus used for hashing. Without the option -key the hash key (modulus and generator) is read from a config file .hashkey in the user's home directory. If the config file does not exist, default values for n and g are used. In any case a hash modulus must be at least 1024 bits long.
If no arguments are given, stdin is used and the message can be piped into the program.


-256 The hash value has a fixed length of 256 bits.


The hash value is computed using one single operation of modular exponentiation. The default is fast, computing the hash values without prior conversion of the message into a long integer.

-key file

Reads the modulus and generator from a file.


$HOME/.hashkey Holds the modulus and generator values. The format of this file comprising 3 lines is :
     Hashmodulus = [1-9][0-9]*
     Generator = [1-9][0-9]*
     User's identification string 
Hashkey files given on the command line will overwrite the configuration file.


Written by Ralf Senderek.


All rights reserved. © 2003
This is free software. Use this software on your own risk or not at all. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


pcp - the Pure Crypto Program (