Provided by: libcrypt-openssl-rsa-perl_0.33-1_amd64 
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);
$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(); # insecure. use_sha256_hash or use_sha1_hash are 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/DER-encoding 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".
An optional parameter can be passed for passphase protected private key:
passphase
The passphase which protects the private key.
generate_key
Create a new "Crypt::OpenSSL::RSA" object by constructing a private/public key pair.
The first (mandatory) 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/DER-encoded 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/DER-encoded 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 Base64/DER-encoded PKCS1 representation of the private key. This string
has header and footer lines:
-----BEGIN RSA PRIVATE KEY------
-----END RSA PRIVATE KEY------
2 optional parameters can be passed for passphase protected private key string:
passphase
The passphase which protects the private key.
cipher name
The cipher algorithm used to protect the private key. Default to 'des3'.
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 "EME-OAEP" padding as defined in PKCS #1 v2.0 with SHA-1, 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 SSL-specific modification that denotes that the
server is SSL3 capable.
Not available since OpenSSL 3.
use_md5_hash
Use the RFC 1321 MD5 hashing algorithm by Ron Rivest when signing and verifying
messages.
Note that this is considered insecure.
use_sha1_hash
Use the RFC 3174 Secure Hashing Algorithm (FIPS 180-1) when signing and verifying
messages. This is the default, when use_sha256_hash is not available.
use_sha224_hash, use_sha256_hash, use_sha384_hash, use_sha512_hash
These FIPS 180-2 hash algorithms, for use when signing and verifying messages, are
only available with newer openssl versions (>= 0.9.8).
use_sha256_hash is the default hash mode when available.
use_ripemd160_hash
Dobbertin, Bosselaers and Preneel's RIPEMD hashing algorithm when signing and
verifying messages.
use_whirlpool_hash
Vincent Rijmen und Paulo S. L. M. Barreto ISO/IEC 10118-3:2004 WHIRLPOOL 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 (p-1)", "d mod (q-1)", 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, "iroberts@cpan.org". For support, please email
"perl-openssl-users@lists.sourceforge.net".
ACKNOWLEDGEMENTS
LICENSE
Copyright (c) 2001-2011 Ian Robertson. Crypt::OpenSSL::RSA is free software; you may
redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
perl(1), Crypt::OpenSSL::Random, Crypt::OpenSSL::Bignum, rsa(3), RSA_new(3)
<http://man.he.net/?topic=RSA_new§ion=3>, RSA_public_encrypt(3)
<http://man.he.net/?topic=RSA_public_encrypt§ion=3>, RSA_size(3)
<http://man.he.net/?topic=RSA_size§ion=3>, RSA_generate_key(3)
<http://man.he.net/?topic=RSA_generate_key§ion=3>, RSA_check_key(3)
<http://man.he.net/?topic=RSA_check_key§ion=3>