NAME

Crypt::PK::DH - Public key cryptography based on Diffie-Hellman

SYNOPSIS

 ### OO interface
 
 #Encryption: Alice
 my $pub = Crypt::PK::DH->new('Bob_pub_dh1.der'); 
 my $ct = $pub->encrypt("secret message");
 #
 #Encryption: Bob (received ciphertext $ct)
 my $priv = Crypt::PK::DH->new('Bob_priv_dh1.der');
 my $pt = $priv->decrypt($ct);
  
 #Signature: Alice
 my $priv = Crypt::PK::DH->new('Alice_priv_dh1.der');
 my $sig = $priv->sign($message);
 #
 #Signature: Bob (received $message + $sig)
 my $pub = Crypt::PK::DH->new('Alice_pub_dh1.der');
 $pub->verify($sig, $message) or die "ERROR";
 
 #Shared secret
 my $priv = Crypt::PK::DH->new('Alice_priv_dh1.der');
 my $pub = Crypt::PK::DH->new('Bob_pub_dh1.der'); 
 my $shared_secret = $priv->shared_secret($pub);

 #Key generation
 my $pk = Crypt::PK::DH->new();
 $pk->generate_key(128);
 my $private = $pk->export_key('private');
 my $public = $pk->export_key('public');
 
 ### Functional interface
 
 #Encryption: Alice
 my $ct = dh_encrypt('Bob_pub_dh1.der', "secret message");
 #Encryption: Bob (received ciphertext $ct)
 my $pt = dh_decrypt('Bob_priv_dh1.der', $ct);
  
 #Signature: Alice
 my $sig = dh_sign('Alice_priv_dh1.der', $message);
 #Signature: Bob (received $message + $sig)
 dh_verify('Alice_pub_dh1.der', $sig, $message) or die "ERROR";
 
 #Shared secret
 my $shared_secret = dh_shared_secret('Alice_priv_dh1.der', 'Bob_pub_dh1.der');

FUNCTIONS

dh_encrypt

dh_decrypt

dh_sign

dh_verify

dh_shared_secret

METHODS

new

  my $pk = Crypt::PK::DH->new();
  #or
  my $pk = Crypt::PK::DH->new($priv_or_pub_key_filename);
  #or
  my $pk = Crypt::PK::DH->new(\$buffer_containing_priv_or_pub_key);

generate_key

Uses Yarrow-based cryptographically strong random number generator seeded with random data taken from /dev/random (UNIX) or CryptGenRandom (Win32).

 $pk->generate_key($keysize);
 # $keysize:
 # 96   =>  DH-768
 # 128  =>  DH-1024
 # 160  =>  DH-1280
 # 192  =>  DH-1536
 # 224  =>  DH-1792
 # 256  =>  DH-2048
 # 320  =>  DH-2560
 # 384  =>  DH-3072
 # 512  =>  DH-4096

import_key

  $pk->import_key($filename);
  #or
  $pk->import_key(\$buffer_containing_key);

export_key

 my $private = $pk->export_key('private');
 #or
 my $public = $pk->export_key('public');

encrypt

decrypt

sign

verify

shared_secret

  # Alice having her priv key $pk and Bob's public key $pkb
  my $pk  = Crypt::PK::DH->new($priv_key_filename);
  my $pkb = Crypt::PK::DH->new($pub_key_filename);
  my $shared_secret = $pk->shared_secret($pkb);

  # Bob having his priv key $pk and Alice's public key $pka
  my $pk = Crypt::PK::DH->new($priv_key_filename);
  my $pka = Crypt::PK::DH->new($pub_key_filename);
  my $shared_secret = $pk->shared_secret($pka);  # same value as computed by Alice

is_private

size