function generate($key_len = null)
{
if (is_null($key_len)) {
// use an old key length
$key_len = $this->_key_len;
if (is_null($key_len)) {
$this->pushError('missing key_len parameter', CRYPT_RSA_ERROR_MISSING_KEY_LEN);
return false;
}
}
// minimal key length is 8 bit ;)
if ($key_len < 8) {
$key_len = 8;
}
// store key length in the _key_len property
$this->_key_len = $key_len;
// set [e] to 0x10001 (65537)
$e = $this->_math_obj->bin2int("");
// generate [p], [q] and [n]
$p_len = intval(($key_len + 1) / 2);
$q_len = $key_len - $p_len;
$p1 = $q1 = 0;
do {
// generate prime number [$p] with length [$p_len] with the following condition:
// GCD($e, $p - 1) = 1
do {
$p = $this->_math_obj->getPrime($p_len, $this->_random_generator);
$p1 = $this->_math_obj->dec($p);
$tmp = $this->_math_obj->GCD($e, $p1);
} while (!$this->_math_obj->isOne($tmp));
// generate prime number [$q] with length [$q_len] with the following conditions:
// GCD($e, $q - 1) = 1
// $q != $p
do {
$q = $this->_math_obj->getPrime($q_len, $this->_random_generator);
$q1 = $this->_math_obj->dec($q);
$tmp = $this->_math_obj->GCD($e, $q1);
} while (!$this->_math_obj->isOne($tmp) && !$this->_math_obj->cmpAbs($q, $p));
// if (p < q), then exchange them
if ($this->_math_obj->cmpAbs($p, $q) < 0) {
$tmp = $p;
$p = $q;
$q = $tmp;
$tmp = $p1;
$p1 = $q1;
$q1 = $tmp;
}
// calculate n = p * q
$n = $this->_math_obj->mul($p, $q);
} while ($this->_math_obj->bitLen($n) != $key_len);
// calculate d = 1/e mod (p - 1) * (q - 1)
$pq = $this->_math_obj->mul($p1, $q1);
$d = $this->_math_obj->invmod($e, $pq);
// calculate dmp1 = d mod (p - 1)
$dmp1 = $this->_math_obj->mod($d, $p1);
// calculate dmq1 = d mod (q - 1)
$dmq1 = $this->_math_obj->mod($d, $q1);
// calculate iqmp = 1/q mod p
$iqmp = $this->_math_obj->invmod($q, $p);
// store RSA keypair attributes
$this->_attrs = array('version' => "", 'n' => $this->_math_obj->int2bin($n), 'e' => $this->_math_obj->int2bin($e), 'd' => $this->_math_obj->int2bin($d), 'p' => $this->_math_obj->int2bin($p), 'q' => $this->_math_obj->int2bin($q), 'dmp1' => $this->_math_obj->int2bin($dmp1), 'dmq1' => $this->_math_obj->int2bin($dmq1), 'iqmp' => $this->_math_obj->int2bin($iqmp));
$n = $this->_attrs['n'];
$e = $this->_attrs['e'];
$d = $this->_attrs['d'];
// try to create public key object
$obj = new Crypt_RSA_Key($n, $e, 'public', $this->_math_obj->getWrapperName(), $this->_error_handler);
if ($obj->isError()) {
// error during creating public object
$this->pushError($obj->getLastError());
return false;
}
$this->_public_key =& $obj;
// try to create private key object
$obj = new Crypt_RSA_Key($n, $d, 'private', $this->_math_obj->getWrapperName(), $this->_error_handler);
if ($obj->isError()) {
// error during creating private key object
$this->pushError($obj->getLastError());
return false;
}
$this->_private_key =& $obj;
return true;
// key pair successfully generated
}
/**
* Crypt_RSA_Key factory.
*
* @param string $modulus key modulus
* @param string $exp key exponent
* @param string $key_type type of the key (public or private)
*
* @param string $wrapper_name
* Name of math wrapper, which will be used to
* perform different operations with big integers.
* See contents of Crypt/RSA/Math folder for examples of wrappers.
* Read docs/Crypt_RSA/docs/math_wrappers.txt for details.
*
* @return object new Crypt_RSA_Key object on success or PEAR_Error object on failure
* @access public
*/
function &factory($modulus, $exp, $key_type, $wrapper_name = 'default')
{
$obj = new Crypt_RSA_Key($modulus, $exp, $key_type, $wrapper_name);
if ($obj->isError()) {
// error during creating a new object. Retrurn PEAR_Error object
return $obj->getLastError();
}
// object created successfully. Return it
return $obj;
}
/**
* Generates new Crypt_RSA key pair with length $key_len.
* If $key_len is missed, use an old key length from $this->_key_len
*
* @param int $key_len bit length of key pair, which will be generated
* @return bool true on success or false on error
* @access public
*/
function generate($key_len = null)
{
if (is_null($key_len)) {
// use an old key length
$key_len = $this->_key_len;
if (is_null($key_len)) {
$obj = PEAR::raiseError('missing key_len parameter', CRYPT_RSA_ERROR_MISSING_KEY_LEN);
$this->pushError($obj);
return false;
}
}
// align $key_len to 8 bits
if ($key_len & 7) {
$key_len += 8 - $key_len % 8;
}
// store key length in the _key_len property
$this->_key_len = $key_len;
// generate two primes p and q
$p_len = (int) ($key_len / 2) + 1;
$q_len = $key_len - $p_len;
$p = $this->_math_obj->getRand($p_len, $this->_random_generator, true);
$p = $this->_math_obj->nextPrime($p);
do {
do {
$q = $this->_math_obj->getRand($q_len, $this->_random_generator, true);
$tmp_len = $this->_math_obj->bitLen($this->_math_obj->mul($p, $q));
if ($tmp_len < $key_len) {
$q_len++;
} elseif ($tmp_len > $key_len) {
$q_len--;
}
} while ($tmp_len != $key_len);
$q = $this->_math_obj->nextPrime($q);
$tmp = $this->_math_obj->mul($p, $q);
} while ($this->_math_obj->bitLen($tmp) != $key_len);
// $n - is shared modulus
$n = $this->_math_obj->mul($p, $q);
// generate public ($e) and private ($d) keys
$pq = $this->_math_obj->mul($this->_math_obj->dec($p), $this->_math_obj->dec($q));
do {
$e = $this->_math_obj->getRand($q_len, $this->_random_generator);
if ($this->_math_obj->isZero($e) || $this->_math_obj->isZero($this->_math_obj->dec($e))) {
// exponent cannot be equal to 0 or 1
continue;
}
if ($this->_math_obj->isZero($this->_math_obj->dec($this->_math_obj->gcd($e, $pq)))) {
// exponent is found
break;
}
} while (true);
$d = $this->_math_obj->invmod($e, $pq);
$modulus = $this->_math_obj->int2bin($n);
$public_exp = $this->_math_obj->int2bin($e);
$private_exp = $this->_math_obj->int2bin($d);
// try to create public key object
$obj = new Crypt_RSA_Key($modulus, $public_exp, 'public', $this->_math_obj->getWrapperName(), $this->_error_handler);
if ($obj->isError()) {
// error during creating public object
$this->pushError($obj->getLastError());
return false;
}
$this->_public_key = $obj;
// try to create private key object
$obj = new Crypt_RSA_Key($modulus, $private_exp, 'private', $this->_math_obj->getWrapperName(), $this->_error_handler);
if ($obj->isError()) {
// error during creating private key object
$this->pushError($obj->getLastError());
return false;
}
$this->_private_key = $obj;
return true;
// key pair successfully generated
}
