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NAME

Crypt::PK::ECC - Public key cryptography based on EC

SYNOPSIS

 ### OO interface

 #Encryption: Alice
 my $pub = Crypt::PK::ECC->new('Bob_pub_ecc1.der');
 my $ct = $pub->encrypt("secret message");
 #
 #Encryption: Bob (received ciphertext $ct)
 my $priv = Crypt::PK::ECC->new('Bob_priv_ecc1.der');
 my $pt = $priv->decrypt($ct);

 #Signature: Alice
 my $priv = Crypt::PK::ECC->new('Alice_priv_ecc1.der');
 my $sig = $priv->sign_message($message);
 #
 #Signature: Bob (received $message + $sig)
 my $pub = Crypt::PK::ECC->new('Alice_pub_ecc1.der');
 $pub->verify_message($sig, $message) or die "ERROR";

 #Shared secret
 my $priv = Crypt::PK::ECC->new('Alice_priv_ecc1.der');
 my $pub = Crypt::PK::ECC->new('Bob_pub_ecc1.der');
 my $shared_secret = $priv->shared_secret($pub);

 #Key generation
 my $pk = Crypt::PK::ECC->new();
 $pk->generate_key('secp160r1');
 my $private_der = $pk->export_key_der('private');
 my $public_der = $pk->export_key_der('public');
 my $private_pem = $pk->export_key_pem('private');
 my $public_pem = $pk->export_key_pem('public');
 my $public_raw = $pk->export_key_raw('public');

 ### Functional interface

 #Encryption: Alice
 my $ct = ecc_encrypt('Bob_pub_ecc1.der', "secret message");
 #Encryption: Bob (received ciphertext $ct)
 my $pt = ecc_decrypt('Bob_priv_ecc1.der', $ct);

 #Signature: Alice
 my $sig = ecc_sign_message('Alice_priv_ecc1.der', $message);
 #Signature: Bob (received $message + $sig)
 ecc_verify_message('Alice_pub_ecc1.der', $sig, $message) or die "ERROR";

 #Shared secret
 my $shared_secret = ecc_shared_secret('Alice_priv_ecc1.der', 'Bob_pub_ecc1.der');

DESCRIPTION

The module provides a set of core ECC functions as well as implementation of ECDSA and ECDH.

Supports elliptic curves y^2 = x^3 + a*x + b over prime fields Fp = Z/pZ (binary fields not supported).

METHODS

new

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

Support for password protected PEM keys

  my $pk = Crypt::PK::ECC->new($priv_pem_key_filename, $password);
  #or
  my $pk = Crypt::PK::ECC->new(\$buffer_containing_priv_pem_key, $password);

generate_key

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

 $pk->generate_key($curve_name);
 #or
 $pk->generate_key($hashref_with_curve_params);

The following pre-defined $curve_name values are supported:

 # curves from http://www.ecc-brainpool.org/download/Domain-parameters.pdf
 'brainpoolP160r1'
 'brainpoolP192r1'
 'brainpoolP224r1'
 'brainpoolP256r1'
 'brainpoolP320r1'
 'brainpoolP384r1'
 'brainpoolP512r1'
 # curves from http://www.secg.org/collateral/sec2_final.pdf
 'secp112r1'
 'secp112r2'
 'secp128r1'
 'secp128r2'
 'secp160k1'
 'secp160r1'
 'secp160r2'
 'secp192k1'
 'secp192r1'
 'secp224k1'
 'secp224r1'
 'secp256k1' ... used by Bitcoin
 'secp256r1'
 'secp384r1'
 'secp521r1'
 #curves from http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf
 'nistp192'
 'nistp224'
 'nistp256'
 'nistp384'
 'nistp521'
 # curves from ANS X9.62
 'prime192v1'
 'prime192v2'
 'prime192v3'
 'prime239v1'
 'prime239v2'
 'prime239v3'
 'prime256v1' 

Using custom curve parameters:

 $pk->generate_key({ prime    => 'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFF',
                     A        => 'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFC',
                     B        => '22123DC2395A05CAA7423DAECCC94760A7D462256BD56916',
                     Gx       => '7D29778100C65A1DA1783716588DCE2B8B4AEE8E228F1896',
                     Gy       => '38A90F22637337334B49DCB66A6DC8F9978ACA7648A943B0',
                     order    => 'FFFFFFFFFFFFFFFFFFFFFFFF7A62D031C83F4294F640EC13',
                     cofactor => 1 });

See http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf, http://www.secg.org/collateral/sec2_final.pdf, http://www.ecc-brainpool.org/download/Domain-parameters.pdf

import_key

Loads private or public key in DER or PEM format.

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

Support for password protected PEM keys

  $pk->import_key($pem_filename, $password);
  #or
  $pk->import_key(\$buffer_containing_pem_key, $password);

import_key_raw

Import raw public/private key - can load data exported by "export_key_raw".

 $pk->import_key_raw($key, $curve);
 # $key .... data exported by export_key_raw()
 # $curve .. curve name or hashref with curve parameters - same as by generate_key()

export_key_der

 my $private_der = $pk->export_key_der('private');
 #or
 my $public_der = $pk->export_key_der('public');

export_key_pem

 my $private_pem = $pk->export_key_pem('private');
 #or
 my $public_pem = $pk->export_key_pem('public');

Support for password protected PEM keys

 my $private_pem = $pk->export_key_pem('private', $password);
 #or
 my $private_pem = $pk->export_key_pem('private', $password, $cipher);

 # supported ciphers: 'DES-CBC'
 #                    'DES-EDE3-CBC'
 #                    'SEED-CBC'
 #                    'CAMELLIA-128-CBC'
 #                    'CAMELLIA-192-CBC'
 #                    'CAMELLIA-256-CBC'
 #                    'AES-128-CBC'
 #                    'AES-192-CBC'
 #                    'AES-256-CBC' (DEFAULT)

export_key_raw

Export raw public/private key. Public key is exported in ANS X9.63 format (compressed or uncompressed), private key is exported as raw bytes (padded with leading zeros to have the same size as the ECC curve).

 my $pubkey_octets  = $pk->export_key_raw('public');
 #or
 my $pubckey_octets = $pk->export_key_raw('public_compressed');
 #or
 my $privkey_octets = $pk->export_key_raw('private');

encrypt

 my $pk = Crypt::PK::ECC->new($pub_key_filename);
 my $ct = $pk->encrypt($message);
 #or
 my $ct = $pk->encrypt($message, $hash_name);

 #NOTE: $hash_name can be 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest

decrypt

 my $pk = Crypt::PK::ECC->new($priv_key_filename);
 my $pt = $pk->decrypt($ciphertext);

sign_message

 my $pk = Crypt::PK::ECC->new($priv_key_filename);
 my $signature = $priv->sign_message($message);
 #or
 my $signature = $priv->sign_message($message, $hash_name);

 #NOTE: $hash_name can be 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest

verify_message

 my $pk = Crypt::PK::ECC->new($pub_key_filename);
 my $valid = $pub->verify_message($signature, $message)
 #or
 my $valid = $pub->verify_message($signature, $message, $hash_name);

 #NOTE: $hash_name can be 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest

sign_hash

 my $pk = Crypt::PK::ECC->new($priv_key_filename);
 my $signature = $priv->sign_hash($message_hash);

verify_hash

 my $pk = Crypt::PK::ECC->new($pub_key_filename);
 my $valid = $pub->verify_hash($signature, $message_hash);

shared_secret

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

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

is_private

 my $rv = $pk->is_private;
 # 1 .. private key loaded
 # 0 .. public key loaded
 # undef .. no key loaded

size

 my $size = $pk->size;
 # returns key size in bytes or undef if no key loaded

key2hash

 my $hash = $pk->key2hash;

 # returns hash like this (or undef if no key loaded):
 {
   size           => 20, # integer: key (curve) size in bytes
   type           => 1,  # integer: 1 .. private, 0 .. public
   #curve parameters
   curve_A        => "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFC",
   curve_B        => "1C97BEFC54BD7A8B65ACF89F81D4D4ADC565FA45",
   curve_bits     => 160,
   curve_bytes    => 20,
   curve_cofactor => 1,
   curve_Gx       => "4A96B5688EF573284664698968C38BB913CBFC82",
   curve_Gy       => "23A628553168947D59DCC912042351377AC5FB32",
   curve_name     => "secp160r1",
   curve_order    => "0100000000000000000001F4C8F927AED3CA752257",
   curve_prime    => "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFF",
   #private key
   k              => "B0EE84A749FE95DF997E33B8F333E12101E824C3",
   #public key point coordinates
   pub_x          => "5AE1ACE3ED0AEA9707CE5C0BCE014F6A2F15023A",
   pub_y          => "895D57E992D0A15F88D6680B27B701F615FCDC0F",
 }

FUNCTIONS

ecc_encrypt

Elliptic Curve Diffie-Hellman (ECDH) encryption as implemented by libtomcrypt. See method "encrypt" below.

 my $ct = ecc_encrypt($pub_key_filename, $message);
 #or
 my $ct = ecc_encrypt(\$buffer_containing_pub_key, $message);
 #or
 my $ct = ecc_encrypt($pub_key_filename, $message, $hash_name);

 #NOTE: $hash_name can be 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest

ECCDH Encryption is performed by producing a random key, hashing it, and XOR'ing the digest against the plaintext.

ecc_decrypt

Elliptic Curve Diffie-Hellman (ECDH) decryption as implemented by libtomcrypt. See method "decrypt" below.

 my $pt = ecc_decrypt($priv_key_filename, $ciphertext);
 #or
 my $pt = ecc_decrypt(\$buffer_containing_priv_key, $ciphertext);

ecc_sign_message

Elliptic Curve Digital Signature Algorithm (ECDSA) - signature generation. See method "sign_message" below.

 my $sig = ecc_sign_message($priv_key_filename, $message);
 #or
 my $sig = ecc_sign_message(\$buffer_containing_priv_key, $message);
 #or
 my $sig = ecc_sign_message($priv_key, $message, $hash_name);

ecc_verify_message

Elliptic Curve Digital Signature Algorithm (ECDSA) - signature verification. See method "verify_message" below.

 ecc_verify_message($pub_key_filename, $signature, $message) or die "ERROR";
 #or
 ecc_verify_message(\$buffer_containing_pub_key, $signature, $message) or die "ERROR";
 #or
 ecc_verify_message($pub_key, $signature, $message, $hash_name) or die "ERROR";

ecc_sign_hash

Elliptic Curve Digital Signature Algorithm (ECDSA) - signature generation. See method "sign_hash" below.

 my $sig = ecc_sign_hash($priv_key_filename, $message_hash);
 #or
 my $sig = ecc_sign_hash(\$buffer_containing_priv_key, $message_hash);

ecc_verify_hash

Elliptic Curve Digital Signature Algorithm (ECDSA) - signature verification. See method "verify_hash" below.

 ecc_verify_hash($pub_key_filename, $signature, $message_hash) or die "ERROR";
 #or
 ecc_verify_hash(\$buffer_containing_pub_key, $signature, $message_hash) or die "ERROR";

ecc_shared_secret

Elliptic curve Diffie-Hellman (ECDH) - construct a Diffie-Hellman shared secret with a private and public ECC key. See method "shared_secret" below.

 #on Alice side
 my $shared_secret = ecc_shared_secret('Alice_priv_ecc1.der', 'Bob_pub_ecc1.der');

 #on Bob side
 my $shared_secret = ecc_shared_secret('Bob_priv_ecc1.der', 'Alice_pub_ecc1.der');

OpenSSL interoperability

 ### let's have:
 # ECC private key in PEM format - eckey.priv.pem
 # ECC public key in PEM format  - eckey.pub.pem
 # data file to be signed - input.data

Sign by OpenSSL, verify by Crypt::PK::ECC

Create signature (from commandline):

 openssl dgst -sha1 -sign eckey.priv.pem -out input.sha1-ec.sig input.data

Verify signature (Perl code):

 use Crypt::PK::ECC;
 use Crypt::Digest 'digest_file';
 use File::Slurp 'read_file';

 my $pkec = Crypt::PK::ECC->new("eckey.pub.pem");
 my $signature = read_file("input.sha1-ec.sig", binmode=>':raw');
 my $valid = $pkec->verify_hash($signature, digest_file("SHA1", "input.data"), "SHA1", "v1.5");
 print $valid ? "SUCCESS" : "FAILURE";

Sign by Crypt::PK::ECC, verify by OpenSSL

Create signature (Perl code):

 use Crypt::PK::ECC;
 use Crypt::Digest 'digest_file';
 use File::Slurp 'write_file';

 my $pkec = Crypt::PK::ECC->new("eckey.priv.pem");
 my $signature = $pkec->sign_hash(digest_file("SHA1", "input.data"), "SHA1", "v1.5");
 write_file("input.sha1-ec.sig", {binmode=>':raw'}, $signature);

Verify signature (from commandline):

 openssl dgst -sha1 -verify eckey.pub.pem -signature input.sha1-ec.sig input.data

Keys generated by Crypt::PK::ECC

Generate keys (Perl code):

 use Crypt::PK::ECC;
 use File::Slurp 'write_file';

 my $pkec = Crypt::PK::ECC->new;
 $pkec->generate_key('secp160k1');
 write_file("eckey.pub.der",  {binmode=>':raw'}, $pkec->export_key_der('public'));
 write_file("eckey.priv.der", {binmode=>':raw'}, $pkec->export_key_der('private'));
 write_file("eckey.pub.pem",  $pkec->export_key_pem('public'));
 write_file("eckey.priv.pem", $pkec->export_key_pem('private'));
 write_file("eckey-passwd.priv.pem", $pkec->export_key_pem('private', 'secret'));

Use keys by OpenSSL:

 openssl ec -in eckey.priv.der -text -inform der
 openssl ec -in eckey.priv.pem -text
 openssl ec -in eckey-passwd.priv.pem -text -inform pem -passin pass:secret
 openssl ec -in eckey.pub.der -pubin -text -inform der
 openssl ec -in eckey.pub.pem -pubin -text 

Keys generated by OpenSSL

Generate keys:

 openssl ecparam -param_enc explicit -name prime192v3 -genkey -out eckey.priv.pem
 openssl ec -param_enc explicit -in eckey.priv.pem -out eckey.pub.pem -pubout
 openssl ec -param_enc explicit -in eckey.priv.pem -out eckey.priv.der -outform der
 openssl ec -param_enc explicit -in eckey.priv.pem -out eckey.pub.der -outform der -pubout
 openssl ec -param_enc explicit -in eckey.priv.pem -out eckey.privc.der -outform der -conv_form compressed
 openssl ec -param_enc explicit -in eckey.priv.pem -out eckey.pubc.der -outform der -pubout -conv_form compressed
 openssl ec -param_enc explicit -in eckey.priv.pem -passout pass:secret -des3 -out eckey-passwd.priv.pem

IMPORTANT: it is necessary to use -param_enc explicit option

Load keys (Perl code):

 use Crypt::PK::ECC;
 use File::Slurp 'write_file';

 my $pkec = Crypt::PK::ECC->new;
 $pkec->import_key("eckey.pub.der");
 $pkec->import_key("eckey.pubc.der");
 $pkec->import_key("eckey.priv.der");
 $pkec->import_key("eckey.privc.der");
 $pkec->import_key("eckey.pub.pem");
 $pkec->import_key("eckey.priv.pem");
 $pkec->import_key("eckey-passwd.priv.pem", "secret");

SEE ALSO