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Man page of RSA
RSA
Section: User Contributed Perl Documentation (3pm)
Updated: 20070520
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NAME
Crypt::OpenSSL::RSA  RSA encoding and decoding, using the openSSL libraries
SYNOPSIS
use Crypt::OpenSSL::Random;
use Crypt::OpenSSL::RSA;
# not necessary if we have /dev/random:
Crypt::OpenSSL::Random::random_seed($good_entropy);
Crypt::OpenSSL::RSA>import_random_seed();
$rsa_pub = Crypt::OpenSSL::RSA>new_public_key($key_string);
$rsa_pub>use_sslv23_padding(); # use_pkcs1_oaep_padding is the default
$ciphertext = $rsa>encrypt($plaintext);
$rsa_priv = Crypt::OpenSSL::RSA>new_private_key($key_string);
$plaintext = $rsa>encrypt($ciphertext);
$rsa = Crypt::OpenSSL::RSA>generate_key(1024); # or
$rsa = Crypt::OpenSSL::RSA>generate_key(1024, $prime);
print "private key is:\n", $rsa>get_private_key_string();
print "public key (in PKCS1 format) is:\n",
$rsa>get_public_key_string();
print "public key (in X509 format) is:\n",
$rsa>get_public_key_x509_string();
$rsa_priv>use_md5_hash(); # use_sha1_hash is the default
$signature = $rsa_priv>sign($plaintext);
print "Signed correctly\n" if ($rsa>verify($plaintext, $signature));
DESCRIPTION
Crypt::OpenSSL::RSA provides the ability to RSA encrypt strings which are
somewhat shorter than the block size of a key. It also allows for decryption,
signatures and signature verification.
NOTE: Many of the methods in this package can croak, so use eval, or
Error.pm's try/catch mechanism to capture errors. Also, while some
methods from earlier versions of this package return true on success,
this (never documented) behavior is no longer the case.
Class Methods
 new_public_key

Create a new Crypt::OpenSSL::RSA object by loading a public key in
from a string containing Base64/DERencoding of either the PKCS1 or
X.509 representation of the key. The string should include the
BEGIN... and END... lines.
The padding is set to PKCS1_OAEP, but can be changed with the
use_xxx_padding methods
 new_private_key

Create a new Crypt::OpenSSL::RSA object by loading a private key in
from an string containing the Base64/DER encoding of the PKCS1
representation of the key. The string should include the
BEGIN... and END... lines. The padding is set to
PKCS1_OAEP, but can be changed with use_xxx_padding.
 generate_key

Create a new Crypt::OpenSSL::RSA object by constructing a
private/public key pair. The first (mandetory) argument is the key
size, while the second optional argument specifies the public exponent
(the default public exponent is 65537). The padding is set to
PKCS1_OAEP, but can be changed with use_xxx_padding methods.
 new_key_from_parameters

Given Crypt::OpenSSL::Bignum objects for n, e, and optionally d, p,
and q, where p and q are the prime factors of n, e is the public
exponent and d is the private exponent, create a new
Crypt::OpenSSL::RSA object using these values. If p and q are
provided and d is undef, d is computed. Note that while p and q are
not necessary for a private key, their presence will speed up
computation.
 import_random_seed

Import a random seed from Crypt::OpenSSL::Random, since the OpenSSL
libraries won't allow sharing of random structures across perl XS
modules.
Instance Methods
 DESTROY

Clean up after ourselves. In particular, erase and free the memory
occupied by the RSA key structure.
 get_public_key_string

Return the Base64/DERencoded PKCS1 representation of the public
key. This string has
header and footer lines:
BEGIN RSA PUBLIC KEY
END RSA PUBLIC KEY
 get_public_key_x509_string

Return the Base64/DERencoded representation of the ``subject
public key'', suitable for use in X509 certificates. This string has
header and footer lines:
BEGIN PUBLIC KEY
END PUBLIC KEY
and is the format that is produced by running "openssl rsa pubout".
 get_private_key_string

Return the DERencoded PKCS1 representation of the private key.
 encrypt

Encrypt a binary ``string'' using the public (portion of the) key.
 decrypt

Decrypt a binary ``string''. Croaks if the key is public only.
 private_encrypt

Encrypt a binary ``string'' using the private key. Croaks if the key is
public only.
 public_decrypt

Decrypt a binary ``string'' using the public (portion of the) key.
 sign

Sign a string using the secret (portion of the) key.
 verify

Check the signature on a text.
 use_no_padding

Use raw RSA encryption. This mode should only be used to implement
cryptographically sound padding modes in the application code.
Encrypting user data directly with RSA is insecure.
 use_pkcs1_padding

Use PKCS #1 v1.5 padding. This currently is the most widely used mode
of padding.
 use_pkcs1_oaep_padding

Use EMEOAEP padding as defined in PKCS #1 v2.0 with SHA1, MGF1 and
an empty encoding parameter. This mode of padding is recommended for
all new applications. It is the default mode used by
Crypt::OpenSSL::RSA.
 use_sslv23_padding

Use PKCS #1 v1.5 padding with an SSLspecific modification that
denotes that the server is SSL3 capable.
 use_md5_hash

Use the RFC 1321 MD5 hashing algorithm by Ron Rivest when signing and
verifying messages.
 use_sha1_hash

Use the RFC 3174 Secure Hashing Algorithm (FIPS 1801) when signing
and verifying messages. This is the default.
 use_sha224_hash, use_sha256_hash, use_sha384_hash, use_sha512_hash

These FIPS 1802 hash algorithms, for use when signing and verifying
messages, are only available with newer openssl versions (>= 0.9.8).
 use_ripemd160_hash

Dobbertin, Bosselaers and Preneel's RIPEMD hashing algorithm when
signing and verifying messages.
 size

Returns the size, in bytes, of the key. All encrypted text will be of
this size, and depending on the padding mode used, the length of
the text to be encrypted should be:

 pkcs1_oaep_padding

at most 42 bytes less than this size.
 pkcs1_padding or sslv23_padding

at most 11 bytes less than this size.
 no_padding

exactly this size.

 check_key

This function validates the RSA key, returning a true value if the key
is valid, and a false value otherwise. Croaks if the key is public only.
 get_key_parameters

Return Crypt::OpenSSL::Bignum objects representing the values of n, e,
d, p, q, d mod (p1), d mod (q1), and 1/q mod p, where p and q are
the prime factors of n, e is the public exponent and d is the private
exponent. Some of these values may return as undef; only n and e will
be defined for a public key. The Crypt::OpenSSL::Bignum module must
be installed for this to work.
 is_private

Return true if this is a private key, and false if it is private only.
BUGS
There is a small memory leak when generating new keys of more than 512 bits.
AUTHOR
Ian Robertson, [email protected]. For support, please email
[email protected].
SEE ALSO
perl(1), Crypt::OpenSSL::Random(3), Crypt::OpenSSL::Bignum(3),
rsa(3), RSA_new(3), RSA_public_encrypt(3), RSA_size(3),
RSA_generate_key(3), RSA_check_key(3)
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 Class Methods

 Instance Methods

 BUGS

 AUTHOR

 SEE ALSO

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Time: 04:14:11 GMT, September 24, 2010