[](https://travis-ci.org/toddr/Crypt-OpenSSL-RSA)
# 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/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`.
- 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------
- 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.
- 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 180-1) when signing
and verifying messages. This is the default.
- 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\_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 (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)](http://man.he.net/man1/perl), [Crypt::OpenSSL::Random(3)](http://man.he.net/man3/Crypt::OpenSSL::Random), [Crypt::OpenSSL::Bignum(3)](http://man.he.net/man3/Crypt::OpenSSL::Bignum),
[rsa(3)](http://man.he.net/man3/rsa), [RSA\_new(3)](http://man.he.net/man3/RSA_new), [RSA\_public\_encrypt(3)](http://man.he.net/man3/RSA_public_encrypt), [RSA\_size(3)](http://man.he.net/man3/RSA_size),
[RSA\_generate\_key(3)](http://man.he.net/man3/RSA_generate_key), [RSA\_check\_key(3)](http://man.he.net/man3/RSA_check_key)