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