package Crypt::PK::RSA;

use strict;
use warnings;
our $VERSION = '0.053';

require Exporter; our @ISA = qw(Exporter); ### use Exporter 'import';
our %EXPORT_TAGS = ( all => [qw(rsa_encrypt rsa_decrypt rsa_sign_message rsa_verify_message rsa_sign_hash rsa_verify_hash)] );
our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
our @EXPORT = qw();

use Carp;
use CryptX qw(_encode_json _decode_json);
use Crypt::Digest qw(digest_data digest_data_b64u);
use Crypt::Misc qw(read_rawfile encode_b64u decode_b64u encode_b64 decode_b64 pem_to_der der_to_pem);
use Crypt::PK;

sub new {
  my ($class, $f, $p) = @_;
  my $self = _new();
  $self->import_key($f, $p) if $f;
  return  $self;
}

sub export_key_pem {
  my ($self, $type, $password, $cipher) = @_;
  my $key = $self->export_key_der($type||'');
  return unless $key;

  # PKCS#1 RSAPrivateKey**           (PEM header: BEGIN RSA PRIVATE KEY)
  # PKCS#8 PrivateKeyInfo*           (PEM header: BEGIN PRIVATE KEY)
  # PKCS#8 EncryptedPrivateKeyInfo** (PEM header: BEGIN ENCRYPTED PRIVATE KEY)
  return der_to_pem($key, "RSA PRIVATE KEY", $password, $cipher) if $type eq 'private';

  # PKCS#1 RSAPublicKey* (PEM header: BEGIN RSA PUBLIC KEY)
  return der_to_pem($key, "RSA PUBLIC KEY") if $type eq 'public';
  # X.509 SubjectPublicKeyInfo** (PEM header: BEGIN PUBLIC KEY)
  return der_to_pem($key, "PUBLIC KEY") if $type eq 'public_x509';
}

sub export_key_jwk {
  my ($self, $type, $wanthash) = @_;
  my $kh = $self->key2hash;
  if ($type eq 'private') {
    return unless $kh->{N} && $kh->{e} && $kh->{d} && $kh->{p} && $kh->{q} && $kh->{dP} && $kh->{dQ} && $kh->{qP};
    for (qw/N e d p q dP dQ qP/) {
      $kh->{$_} = "0$kh->{$_}" if length($kh->{$_}) % 2;
    }
    my $hash = {
      kty => "RSA",
      n   => encode_b64u(pack("H*", $kh->{N})),
      e   => encode_b64u(pack("H*", $kh->{e})),
      d   => encode_b64u(pack("H*", $kh->{d})),
      p   => encode_b64u(pack("H*", $kh->{p})),
      q   => encode_b64u(pack("H*", $kh->{q})),
      dp  => encode_b64u(pack("H*", $kh->{dP})),
      dq  => encode_b64u(pack("H*", $kh->{dQ})),
      qi  => encode_b64u(pack("H*", $kh->{qP})),
    };
    return $wanthash ? $hash : _encode_json($hash);
  }
  elsif ($type eq 'public') {
    return unless $kh->{N} && $kh->{e};
    for (qw/N e/) {
      $kh->{$_} = "0$kh->{$_}" if length($kh->{$_}) % 2;
    }
    my $hash = {
      kty => "RSA",
      n   => encode_b64u(pack("H*", $kh->{N})),
      e   => encode_b64u(pack("H*", $kh->{e})),
    };
    return $wanthash ? $hash : _encode_json($hash);
  }
}

sub export_key_jwk_thumbprint {
  my ($self, $hash_name) = @_;
  $hash_name ||= 'SHA256';
  my $h = $self->export_key_jwk('public', 1);
  my $json = _encode_json({kty=>$h->{kty}, n=>$h->{n}, e=>$h->{e}});
  return digest_data_b64u($hash_name, $json);
}

sub import_key {
  my ($self, $key, $password) = @_;
  croak "FATAL: undefined key" unless $key;

  # special case
  if (ref($key) eq 'HASH') {
    if ($key->{N} && $key->{e}) {
      # hash exported via key2hash
      return $self->_import_hex($key->{N}, $key->{e}, $key->{d}, $key->{p}, $key->{q}, $key->{dP}, $key->{dQ}, $key->{qP});
    }
    if ($key->{n} && $key->{e} && $key->{kty} && $key->{kty} eq "RSA") {
      $key = {%$key};   #make a copy so that the modifications below stay local

      # hash with items corresponding to JSON Web Key (JWK)
      for (qw/n e d p q dp dq qi/) {
        $key->{$_} = eval { unpack("H*", decode_b64u($key->{$_})) } if exists $key->{$_};
      }
      return $self->_import_hex($key->{n}, $key->{e}, $key->{d}, $key->{p}, $key->{q}, $key->{dp}, $key->{dq}, $key->{qi});
    }
    croak "FATAL: unexpected RSA key hash";
  }

  my $data;
  if (ref($key) eq 'SCALAR') {
    $data = $$key;
  }
  elsif (-f $key) {
    $data = read_rawfile($key);
  }
  else {
    croak "FATAL: non-existing file '$key'";
  }
  croak "FATAL: invalid key data" unless $data;

  if ($data =~ /-----BEGIN (RSA PRIVATE|RSA PUBLIC|PUBLIC) KEY-----(.*?)-----END/sg) {
    # PKCS#1 RSAPublicKey        (PEM header: BEGIN RSA PUBLIC KEY)
    # PKCS#1 RSAPrivateKey       (PEM header: BEGIN RSA PRIVATE KEY)
    # X.509 SubjectPublicKeyInfo (PEM header: BEGIN PUBLIC KEY)
    $data = pem_to_der($data, $password);
    return $self->_import($data) if $data;
  }
  elsif ($data =~ /-----BEGIN PRIVATE KEY-----(.*?)-----END/sg) {
    # PKCS#8 PrivateKeyInfo      (PEM header: BEGIN PRIVATE KEY)
    $data = pem_to_der($data, $password);
    return $self->_import_pkcs8($data, $password) if $data;
  }
  elsif ($data =~ /-----BEGIN ENCRYPTED PRIVATE KEY-----(.*?)-----END/sg) {
    # XXX-TODO: PKCS#8 EncryptedPrivateKeyInfo (PEM header: BEGIN ENCRYPTED PRIVATE KEY)
    croak "FATAL: encrypted pkcs8 RSA private keys are not supported";
  }
  elsif ($data =~ /^\s*(\{.*?\})\s*$/s) {
    # JSON Web Key (JWK) - http://tools.ietf.org/html/draft-ietf-jose-json-web-key
    my $json = "$1";
    my $h = _decode_json($json);
    if ($h && $h->{kty} eq "RSA") {
      for (qw/n e d p q dp dq qi/) {
        $h->{$_} = eval { unpack("H*", decode_b64u($h->{$_})) } if exists $h->{$_};
      }
      return $self->_import_hex($h->{n}, $h->{e}, $h->{d}, $h->{p}, $h->{q}, $h->{dp}, $h->{dq}, $h->{qi}) if $h->{n} && $h->{e};
    }
  }
  elsif ($data =~ /-----BEGIN CERTIFICATE-----(.*?)-----END CERTIFICATE-----/sg) {
    $data = pem_to_der($data);
    return $self->_import_x509($data);
  }
  elsif ($data =~ /---- BEGIN SSH2 PUBLIC KEY ----(.*?)---- END SSH2 PUBLIC KEY ----/sg) {
    $data = pem_to_der($data);
    my ($typ, $N, $e) = Crypt::PK::_ssh_parse($data);
    return $self->_import_hex(unpack("H*", $e), unpack("H*", $N)) if $typ && $e && $N && $typ eq 'ssh-rsa';
  }
  elsif ($data =~ /ssh-rsa\s+(\S+)/) {
  $data = decode_b64("$1");
    my ($typ, $N, $e) = Crypt::PK::_ssh_parse($data);
    return $self->_import_hex(unpack("H*", $e), unpack("H*", $N)) if $typ && $e && $N && $typ eq 'ssh-rsa';
  }
  else {
    # DER format
    my $rv = eval { $self->_import($data) } || eval { $self->_import_pkcs8($data, $password) } || eval { $self->_import_x509($data) };
    return $rv if $rv;
  }

  croak "FATAL: invalid or unsupported RSA key format";
}

sub encrypt {
  my ($self, $data, $padding, $hash_name, $lparam) = @_;
  $lparam ||= '';
  $padding ||= 'oaep';
  $hash_name = Crypt::Digest::_trans_digest_name($hash_name||'SHA1');

  return $self->_encrypt($data, $padding, $hash_name, $lparam);
}

sub decrypt {
  my ($self, $data, $padding, $hash_name, $lparam) = @_;
  $lparam ||= '';
  $padding ||= 'oaep';
  $hash_name = Crypt::Digest::_trans_digest_name($hash_name||'SHA1');

  return $self->_decrypt($data, $padding, $hash_name, $lparam);
}

sub sign_hash {
  my ($self, $data, $hash_name, $padding, $saltlen) = @_;
  $saltlen ||= 12;
  $padding ||= 'pss';
  $hash_name = Crypt::Digest::_trans_digest_name($hash_name||'SHA1');

  return $self->_sign($data, $padding, $hash_name, $saltlen);
}

sub sign_message {
  my ($self, $data, $hash_name, $padding, $saltlen) = @_;
  $saltlen ||= 12;
  $padding ||= 'pss';
  $hash_name = Crypt::Digest::_trans_digest_name($hash_name||'SHA1');

  return $self->_sign(digest_data($hash_name, $data), $padding, $hash_name, $saltlen);
}

sub verify_hash {
  my ($self, $sig, $data, $hash_name, $padding, $saltlen) = @_;
  $saltlen ||= 12;
  $padding ||= 'pss';
  $hash_name = Crypt::Digest::_trans_digest_name($hash_name||'SHA1');

  return $self->_verify($sig, $data, $padding, $hash_name, $saltlen);
}

sub verify_message {
  my ($self, $sig, $data, $hash_name, $padding, $saltlen) = @_;
  $saltlen ||= 12;
  $padding ||= 'pss';
  $hash_name = Crypt::Digest::_trans_digest_name($hash_name||'SHA1');

  return $self->_verify($sig, digest_data($hash_name, $data), $padding, $hash_name, $saltlen);
}

### FUNCTIONS

sub rsa_encrypt {
  my $key = shift;
  $key = __PACKAGE__->new($key) unless ref $key;
  carp "FATAL: invalid 'key' param" unless ref($key) eq __PACKAGE__;
  return $key->encrypt(@_);
}

sub rsa_decrypt {
  my $key = shift;
  $key = __PACKAGE__->new($key) unless ref $key;
  carp "FATAL: invalid 'key' param" unless ref($key) eq __PACKAGE__;
  return $key->decrypt(@_);
}

sub rsa_sign_hash {
  my $key = shift;
  $key = __PACKAGE__->new($key) unless ref $key;
  carp "FATAL: invalid 'key' param" unless ref($key) eq __PACKAGE__;
  return $key->sign_hash(@_);
}

sub rsa_verify_hash {
  my $key = shift;
  $key = __PACKAGE__->new($key) unless ref $key;
  carp "FATAL: invalid 'key' param" unless ref($key) eq __PACKAGE__;
  return $key->verify_hash(@_);
}

sub rsa_sign_message {
  my $key = shift;
  $key = __PACKAGE__->new($key) unless ref $key;
  carp "FATAL: invalid 'key' param" unless ref($key) eq __PACKAGE__;
  return $key->sign_message(@_);
}

sub rsa_verify_message {
  my $key = shift;
  $key = __PACKAGE__->new($key) unless ref $key;
  carp "FATAL: invalid 'key' param" unless ref($key) eq __PACKAGE__;
  return $key->verify_message(@_);
}

sub CLONE_SKIP { 1 } # prevent cloning

1;

=pod

=head1 NAME

Crypt::PK::RSA - Public key cryptography based on RSA

=head1 SYNOPSIS

 ### OO interface

 #Encryption: Alice
 my $pub = Crypt::PK::RSA->new('Bob_pub_rsa1.der');
 my $ct = $pub->encrypt("secret message");
 #
 #Encryption: Bob (received ciphertext $ct)
 my $priv = Crypt::PK::RSA->new('Bob_priv_rsa1.der');
 my $pt = $priv->decrypt($ct);

 #Signature: Alice
 my $priv = Crypt::PK::RSA->new('Alice_priv_rsa1.der');
 my $sig = $priv->sign_message($message);
 #
 #Signature: Bob (received $message + $sig)
 my $pub = Crypt::PK::RSA->new('Alice_pub_rsa1.der');
 $pub->verify_message($sig, $message) or die "ERROR";

 #Key generation
 my $pk = Crypt::PK::RSA->new();
 $pk->generate_key(256, 65537);
 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');

 ### Functional interface

 #Encryption: Alice
 my $ct = rsa_encrypt('Bob_pub_rsa1.der', "secret message");
 #Encryption: Bob (received ciphertext $ct)
 my $pt = rsa_decrypt('Bob_priv_rsa1.der', $ct);

 #Signature: Alice
 my $sig = rsa_sign_message('Alice_priv_rsa1.der', $message);
 #Signature: Bob (received $message + $sig)
 rsa_verify_message('Alice_pub_rsa1.der', $sig, $message) or die "ERROR";

=head1 DESCRIPTION

The module provides a full featured RSA implementation.

=head1 METHODS

=head2 new

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

Support for password protected PEM keys

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

=head2 generate_key

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

 $pk->generate_key($size, $e);
 # $size .. key size: 128-512 bytes (DEFAULT is 256)
 # $e ..... exponent: 3, 17, 257 or 65537 (DEFAULT is 65537)

=head2 import_key

Loads private or public key in DER or PEM format.

  $pk->import_key($priv_or_pub_key_filename);
  #or
  $pk->import_key(\$buffer_containing_priv_or_pub_key);

Support for password protected PEM keys

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

Loading private or public keys form perl hash:

 $pk->import_key($hashref);

 # the $hashref is either a key exported via key2hash
 $pk->import_key({
   e  => "10001", #public exponent
   d  => "9ED5C3D3F866E06957CA0E9478A273C39BBDA4EEAC5B...", #private exponent
   N  => "D0A5CCCAE03DF9C2F5C4C8C0CE840D62CDE279990DC6...", #modulus
   p  => "D3EF0028FFAB508E2773C659E428A80FB0E9211346B4...", #p factor of N
   q  => "FC07E46B163CAB6A83B8E467D169534B2077DCDEECAE...", #q factor of N
   qP => "88C6D406F833DF73C8B734548E0385261AD51F4187CF...", #1/q mod p CRT param
   dP => "486F142FEF0A1F53269AC43D2EE4D263E2841B60DA36...", #d mod (p - 1) CRT param
   dQ => "4597284B2968B72C4212DB7E8F24360B987B80514DA9...", #d mod (q - 1) CRT param
 });

 # or a hash with items corresponding to JWK (JSON Web Key)
 $pk->import_key({
 {
   kty => "RSA",
   n   => "0vx7agoebGcQSuuPiLJXZpt...eZu0fM4lFd2NcRwr3XPksINHaQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw",
   e   => "AQAB",
   d   => "X4cTteJY_gn4FYPsXB8rdXi...FLN5EEaG6RoVH-HLKD9Mdx5ooGURknhnrRwUkC7h5fJLMWbFAKLWY2v7B6NqSzUvx0_YSf",
   p   => "83i-7IvMGXoMXCskv73TKr8...Z27zvoj6pbUQyLPBQxtPnwD20-60eTmD2ujMt5PoMrm8RmNhVWtjjMmMjOpSicFHjXOuVI",
   q   => "3dfOR9cuYq-0S-mkFLzgItg...q3hWeMuG0ouqnb3obLyuqjVZQ1dIrdgTnCdYzBcOW5r37AFXjift_NGiovonzhKpoVVS78",
   dp  => "G4sPXkc6Ya9y8oJW9_ILj4...zi_H7TkS8x5SdX3oE0oiYwxIiemTAu0UOa5pgFGyJ4c8t2VF40XRugKTP8akhFo5tA77Qe",
   dq  => "s9lAH9fggBsoFR8Oac2R_E...T2kGOhvIllTE1efA6huUvMfBcpn8lqW6vzzYY5SSF7pMd_agI3G8IbpBUb0JiraRNUfLhc",
   qi  => "GyM_p6JrXySiz1toFgKbWV...4ypu9bMWx3QJBfm0FoYzUIZEVEcOqwmRN81oDAaaBk0KWGDjJHDdDmFW3AN7I-pux_mHZG",
 });

Supported key formats:

 # all formats can be loaded from a file
 my $pk = Crypt::PK::RSA->new($filename);

 # or from a buffer containing the key
 my $pk = Crypt::PK::RSA->new(\$buffer_with_key);

=over

=item * RSA public keys

 -----BEGIN PUBLIC KEY-----
 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDHlYKg9DeHB3/dY1D9WCyJTnl5
 vEzAXpUOL9tDtdPUl96brIbbdMLooO1hKjsq98kLs1q4vOn/pxvzk0BRwhiu7Vvb
 VUjAn/2HHDDL0U1utqqlMJhaffeLI3HEq5o/lSMFY7sSkZU/E4YX1yqAN0SE7xfK
 B2uzcNq60sMIfp6siQIDAQAB
 -----END PUBLIC KEY-----

=item * RSA private keys

 -----BEGIN RSA PRIVATE KEY-----
 MIICXQIBAAKBgQDHlYKg9DeHB3/dY1D9WCyJTnl5vEzAXpUOL9tDtdPUl96brIbb
 dMLooO1hKjsq98kLs1q4vOn/pxvzk0BRwhiu7VvbVUjAn/2HHDDL0U1utqqlMJha
 ffeLI3HEq5o/lSMFY7sSkZU/E4YX1yqAN0SE7xfKB2uzcNq60sMIfp6siQIDAQAB
 AoGBAI5+GgNcGQDYw9uF+t7FwxZM5sGZRJrbbEPyuvL+sDxKKW6voKCyHi4EJzaF
 9jRZMDqgVJcsmUwjPPuMGBHHJ+MI5Zb3L0jbZkyx8u+U5gf88oy9eZmfGOjmHcMB
 oCgzyoLmJETuyADg2onLanuY3jggFb3tq/jimKjO8xM2R6zhAkEA7uXWWyJI9cCN
 zrVt5R5v6oosjZ4r5VILGMqBRLrzfTvH+WDMK6Rl/2MHE+YDeLajzunaM8qY2456
 GTYEXQsIdQJBANXfMEtXocSdPtoVj3ME8Do/0r+ApgTdcDPCwXOzkmkEJW/UFMSn
 b8CYF5G6sZQN9L5z3s2nvi55PaFV8Q0LMUUCQBh9GvIQm6YFbQPpeTBpZFOIgnSp
 6BoDxPtvlryy5U7LF/6qO4OlwIbjYdBaXbS8FCKbujBg7jZjboSzEtNu1BkCQDGT
 w0Yz0jQZn3A+fzpScr2N/fSWheWqz0+wXdfMUKw3YdZCe236wlUK7KvDc1a2xX1A
 ru1NbTCoujikC3TSm2ECQQDKQshchJlZJmFv9vCFQlGCA/EX+4406xvOOiixbPYC
 pIB4Ee2cmvEdAqSaOjrvgs5zvaCCFBO0MecPStCAxUX6
 -----END RSA PRIVATE KEY-----

=item * RSA private keys in password protected PEM format

 -----BEGIN RSA PRIVATE KEY-----
 Proc-Type: 4,ENCRYPTED
 DEK-Info: DES-EDE3-CBC,4D697440FF5AEF18

 C09H49Gn99o8b8O2r4+Hqao4r3udvC+QSSfsk20sXatyuZSEmbhyqKAB+13NRj+3
 KIsRTqnL9VkeibIGgLHuekOFKAqeSVZ0PmR4bGWEFxUPAYUvg9N9pIa6hGtNZG+y
 TEpOAfFITb1pbHQhp3j8y7qmKc5kY5LrZSFE8WwA24NTG773E07wJgRxKDkXNGOl
 kki6oYArNEps0DdtHFxzgdRg0+yaotXuFJRuC5V4YzKGG/oSRcgYyXKTwCndb3xt
 aHgI2WprQAPg+qOpLABzoi7bEjCqbHWrwkvnAngylbim2Uyvw1e1xKnzlgIHU7pv
 e/J+s00pTItfqW1IpY2mh4C9nkfkfVKBKaAv7jO0s6aPySATqsdlrzv2kpF6Ub4J
 kgaZDOfZ4K3qkyAYVLWcQeDqg4glv9Ah2J05bTm4qrIMmthYnThyQlGvcjUfCMXs
 0t+mEQbsRY7xKt0o6HzzvQlJ+JsFlLORoslAubJX9iLqpEdnlrj1lD9bo6uIClZ5
 5+aoLcAyz1D4OsauuP5i8VFu+Is+QG4SN/vHVuArjkqi3VpLwSAjNDY+KWbq042l
 CqlM2mwm6FIGUZQFxiLHJD7WDmk1xmae++m+XG9CEDTfrUQ5v+l0O6BTrl80XUfU
 w3gzAWbSjz3UK0FpKeABVFPE9fjNP9fTcS6qL5YJWBPflwxCAbVgsBOW4bOMpDGK
 BJDQTeShWn4BlYCe/vgThI9ERdgZhRz4NcFeDgVA/CqQzVqptvz4PSqH46fqUN2n
 4PtJgKE5cASYUBuAjlD71FecSVVM/OTzL1uxYzXBilzvVn2vSHgo9g==
 -----END RSA PRIVATE KEY-----

=item * PKCS#8 encoded private keys

 -----BEGIN PRIVATE KEY-----
 MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBANPN17xW4EkH5PXG
 1i/i3rE1EXFcCHyxmz95VRBDs1p3MuYf9mxntbfYAmuzS3KrRWh3IyX/Eh80N/v9
 OXPlwZbVqSTX+L3pCEJtRtsWn0zmswGThjMZiwle0oWuap63L35F1QN8EDaSPSBC
 yGELNRr6rwVYq0w5b+LOcaCZ+/H1AgMBAAECgYEApfu3aGpww+rC3HUhX0+ckyTy
 cXLdV9LbxidwqRlVEb0+DyfXNucjelp2sy5EHy3na9GJovo8mmWSxhCRGKliRkQ6
 XgrEMZdCSaWI2AazuHAGlUJRFEVkvdla3AuBAn6y0YdDp/3kbg0yahmKyD8Gq74z
 nUYbDL3R5JtR2Ad/KlUCQQDvSEICTHbO/BF7hVmlKRYZSNHKEPrv8X/OlppS14Kv
 QRwc+CZ5+l6T1Y+l5cHJQUXrXZoWS1K741TXdUhjjUd7AkEA4pod804Ex8sttdWi
 pHMfeyj+IbPAk5XnBc91jT7AYIeL8ccjtfl99xhMsGFaxrh3wA/4SGEvwzWkbxcq
 H8G5TwJAKNG+0P2SVwURRm0dOdukdXPCtiHnbP9Zujhe4zr4hEUrMpXymmRntfh8
 pORpBpgoAVraams3Fe5WDttnGfSD+QJAOOC6V9HjfUrQhG3FT0XeRwm5EDiQQ/tC
 a8DxHqz7mL8tL1ju68ReC+G7jiJBqNOwqzLW/UP3uyYByiikWChGHQJAHUau7jIM
 45ErO096n94Vh95p76ANxOroWszOt39TyvJOykIfoPwFagLrBWV9Jjos2/D54KE+
 fyoy4t3yHT+/nw==
 -----END PRIVATE KEY-----

=item * PKCS#8 encrypted private keys ARE NOT SUPPORTED YET!

 -----BEGIN ENCRYPTED PRIVATE KEY-----
 MIICojAcBgoqhkiG9w0BDAEDMA4ECCQk+Rr1yzzcAgIIAASCAoD/mgpUFjxxM/Ty
 Yt+NeT0Fo4echgoGksqs6+rYhO16oshG664emZfkuNoFGGzJ38X6GVuqIXhlPnYQ
 biKvL37dN/KnoGytFHq9Wnk8dDwjGHPtwajhW5WuIV3NuhW/AO1PF/cRZKFjWrPt
 NWY5CrpfH6t6zojoe+5uyXpH29lQy4OqvSRdPIt/12UcB+tzV7XzSWEuXh8HAi8a
 sYUu6tuCFnq4GrD2ffM4KWFmL5GqBAwN6m0KkyrNni9XT+RaA6zEhv/lVcwg2esa
 4/EzRs0ixzzZDKaml8oCMl9RHtFAbQmdlfV7Ip4rGK9BwY6UFiDMIVru6HynOVQK
 vvZ+j//bgO+3ubrv7psX+vC9Fy/MoH2Tc7MIwDN/QVTciPZlzjWBnBNxMfeFKtEn
 d7NFiapgfLuRQIiDTMrW/clcqvO54NphxhrcgUEoxos4twKZARntqPZHtf8nEM2x
 2sEF5kI65aEF/5Yy16qvP0vZAA2B1kcIdXZ8XLZCp4c3olhkIrmgUpo1gyFXdCoC
 7dT5Cz7/YLkq5hkcFrtp4V9BZMR24fSttc4p24N5xuZ+JneGnGkLX6B+nJAtm9vw
 bZA6P+23GI0qeMzL3HJXwCOTSsWfm/H9W5+2Zmw851aAmE+pZLni/pk3e3iNSWgs
 946x/doA5O0uCFsU7oxme+WAIp2SjhxGoe808Lf1CCFMPboFi1O/E0NsX8SIEX+i
 U+UHi4kxZqVkr3Q5SB/9kiSv8K1bE787yueQOT/dsTYYaMsjAbkEZo0o/47F32T6
 A2ioXHOV/pr5zNHqE5tL+qKEcLYbAUF1O+WvmdqYz+vHQjRQBatAqTmncvLDYr/j
 1HPwZX2d
 -----END ENCRYPTED PRIVATE KEY-----

=item * RSA public key from X509 certificate

 -----BEGIN CERTIFICATE-----
 MIIC8zCCAdugAwIBAgIJAPi+LvMU3uGWMA0GCSqGSIb3DQEBCwUAMBAxDjAMBgNV
 BAMMBXBva3VzMB4XDTE3MDcxNDE0MTAyMFoXDTIwMDQwOTE0MTAyMFowEDEOMAwG
 A1UEAwwFcG9rdXMwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDCQima
 SUIMIdz5uVevzcScbcj06xs1OLaFKUoPJ8v+xP6Ut61BQhAvc8GYuw2uRx223hZC
 r3HYLfSdWIfmOIAtlL8cPYPVoSivJtpSGE6fBG1tlBjVgXWRmJGR/oxx6Y5QDwcB
 Q4GZKga8TtHQoY5idZuatYOFZGfMIcIUC0Uoda+YSypnw7A90F/JvlpcTUh3Fnem
 VinqEA6XOegU9dCZk/29sXqauBjbdGihh8DvpklOhY16eQoiR3909AywQ0KUmI+R
 Sa9E8oIsmUDetFuXEvana+sD3y42tU+cd2nhBPRETbSXPcum0B3uF4yKgweuJy5D
 cvtVQIFVkkh4+AWNAgMBAAGjUDBOMB0GA1UdDgQWBBSS6V5PVGyN92NoB0AVLcOb
 pzR3SzAfBgNVHSMEGDAWgBSS6V5PVGyN92NoB0AVLcObpzR3SzAMBgNVHRMEBTAD
 AQH/MA0GCSqGSIb3DQEBCwUAA4IBAQBIszrBjoJ39axsS6Btbvwvo8vAmgiSWsav
 7AmjXOAwknHPaCcDmrdOys5POD0DNRwNeRsnxFiZ/UL8Vmj2JGDLgAw+/v32MwfX
 Ig7m+oIbO8KqDzlYvS5kd3suJ5C21hHy1/JUtfofZLovZH7ZRzhTAoRvCYaodW90
 2o8ZqmyCdcXPzjFmoJ2xYzs/Sf8/E1cHfb+4HjOpeRnKxDvG0gwWzcsXpUrw2pNO
 Oztj6Rd0THNrf/anIeYVtAHX4aqZA8Kbv2TyJd+9g78usFw1cn+8vfmilm6Pn0DQ
 a+I5GyGd7BJI8wYuWqIStzvrJHbQQaNrSk7hgjWYiYlcsPh6w2QP
 -----END CERTIFICATE-----

=item * SSH public RSA keys

 ssh-rsa AAAAB3NzaC1yc2EAAAADAQA...6mdYs5iJNGu/ltUdc=

=item * SSH public RSA keys (RFC-4716 format)

 ---- BEGIN SSH2 PUBLIC KEY ----
 Comment: "768-bit RSA, converted from OpenSSH"
 AAAAB3NzaC1yc2EAAAADAQABAAAAYQDYebeGQFCnlQiNRE7r9UEbjr+DQMTdw1ZHGB2w6x
 D/DzKem8761GdCpqsLrGaw2D7aSIoP1B5Sz870YoVWHn6Ao7Hvm17V3Kxfn4B01GNQTM5+
 L26mdYs5iJNGu/ltUdc=
 ---- END SSH2 PUBLIC KEY ----

=item * RSA private keys in JSON Web Key (JWK) format

See L<http://tools.ietf.org/html/draft-ietf-jose-json-web-key>

 {
   "kty":"RSA",
   "n":"0vx7agoebGcQSuuPiLJXZpt...eZu0fM4lFd2NcRwr3XPksINHaQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw",
   "e":"AQAB",
   "d":"X4cTteJY_gn4FYPsXB8rdXi...FLN5EEaG6RoVH-HLKD9Mdx5ooGURknhnrRwUkC7h5fJLMWbFAKLWY2v7B6NqSzUvx0_YSf",
   "p":"83i-7IvMGXoMXCskv73TKr8...Z27zvoj6pbUQyLPBQxtPnwD20-60eTmD2ujMt5PoMrm8RmNhVWtjjMmMjOpSicFHjXOuVI",
   "q":"3dfOR9cuYq-0S-mkFLzgItg...q3hWeMuG0ouqnb3obLyuqjVZQ1dIrdgTnCdYzBcOW5r37AFXjift_NGiovonzhKpoVVS78",
   "dp":"G4sPXkc6Ya9y8oJW9_ILj4...zi_H7TkS8x5SdX3oE0oiYwxIiemTAu0UOa5pgFGyJ4c8t2VF40XRugKTP8akhFo5tA77Qe",
   "dq":"s9lAH9fggBsoFR8Oac2R_E...T2kGOhvIllTE1efA6huUvMfBcpn8lqW6vzzYY5SSF7pMd_agI3G8IbpBUb0JiraRNUfLhc",
   "qi":"GyM_p6JrXySiz1toFgKbWV...4ypu9bMWx3QJBfm0FoYzUIZEVEcOqwmRN81oDAaaBk0KWGDjJHDdDmFW3AN7I-pux_mHZG",
 }

B<BEWARE:> For JWK support you need to have L<JSON::PP>, L<JSON::XS> or L<Cpanel::JSON::XS> module.

=item * RSA public keys in JSON Web Key (JWK) format

 {
   "kty":"RSA",
   "n": "0vx7agoebGcQSuuPiLJXZp...tN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAtVT86zwu1RK7aPFFxuhDR1L6tSoc_BJECP",
   "e":"AQAB",
 }

B<BEWARE:> For JWK support you need to have L<JSON::PP>, L<JSON::XS> or L<Cpanel::JSON::XS> module.

=back

=head2 export_key_der

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

=head2 export_key_pem

 my $private_pem = $pk->export_key_pem('private');
 #or
 my $public_pem = $pk->export_key_pem('public');
 #or
 my $public_pem = $pk->export_key_pem('public_x509');

With parameter C<'public'> uses header and footer lines:

  -----BEGIN RSA PUBLIC KEY------
  -----END RSA PUBLIC KEY------

With parameter C<'public_x509'> uses header and footer lines:

  -----BEGIN PUBLIC KEY------
  -----END PUBLIC KEY------

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)

=head2 export_key_jwk

I<Since: CryptX-0.022>

Exports public/private keys as a JSON Web Key (JWK).

 my $private_json_text = $pk->export_key_jwk('private');
 #or
 my $public_json_text = $pk->export_key_jwk('public');

Also exports public/private keys as a perl HASH with JWK structure.

 my $jwk_hash = $pk->export_key_jwk('private', 1);
 #or
 my $jwk_hash = $pk->export_key_jwk('public', 1);

B<BEWARE:> For JWK support you need to have L<JSON::PP>, L<JSON::XS> or L<Cpanel::JSON::XS> module.

=head2 export_key_jwk_thumbprint

I<Since: CryptX-0.031>

Exports the key's JSON Web Key Thumbprint as a string.

If you don't know what this is, see RFC 7638 (C<https://tools.ietf.org/html/rfc7638>).

 my $thumbprint = $pk->export_key_jwk_thumbprint('SHA256');

=head2 encrypt

 my $pk = Crypt::PK::RSA->new($pub_key_filename);
 my $ct = $pk->encrypt($message);
 #or
 my $ct = $pk->encrypt($message, $padding);
 #or
 my $ct = $pk->encrypt($message, 'oaep', $hash_name, $lparam);

 # $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none' (INSECURE)
 # $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $lparam (only for oaep) ..... DEFAULT is empty string

=head2 decrypt

 my $pk = Crypt::PK::RSA->new($priv_key_filename);
 my $pt = $pk->decrypt($ciphertext);
 #or
 my $pt = $pk->decrypt($ciphertext, $padding);
 #or
 my $pt = $pk->decrypt($ciphertext, 'oaep', $hash_name, $lparam);

 # $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none' (INSECURE)
 # $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $lparam (only for oaep) ..... DEFAULT is empty string

=head2 sign_message

 my $pk = Crypt::PK::RSA->new($priv_key_filename);
 my $signature = $priv->sign_message($message);
 #or
 my $signature = $priv->sign_message($message, $hash_name);
 #or
 my $signature = $priv->sign_message($message, $hash_name, $padding);
 #or
 my $signature = $priv->sign_message($message, $hash_name, 'pss', $saltlen);

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 verify_message

 my $pk = Crypt::PK::RSA->new($pub_key_filename);
 my $valid = $pub->verify_message($signature, $message);
 #or
 my $valid = $pub->verify_message($signature, $message, $hash_name);
 #or
 my $valid = $pub->verify_message($signature, $message, $hash_name, $padding);
 #or
 my $valid = $pub->verify_message($signature, $message, $hash_name, 'pss', $saltlen);

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 sign_hash

 my $pk = Crypt::PK::RSA->new($priv_key_filename);
 my $signature = $priv->sign_hash($message_hash);
 #or
 my $signature = $priv->sign_hash($message_hash, $hash_name);
 #or
 my $signature = $priv->sign_hash($message_hash, $hash_name, $padding);
 #or
 my $signature = $priv->sign_hash($message_hash, $hash_name, 'pss', $saltlen);

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 verify_hash

 my $pk = Crypt::PK::RSA->new($pub_key_filename);
 my $valid = $pub->verify_hash($signature, $message_hash);
 #or
 my $valid = $pub->verify_hash($signature, $message_hash, $hash_name);
 #or
 my $valid = $pub->verify_hash($signature, $message_hash, $hash_name, $padding);
 #or
 my $valid = $pub->verify_hash($signature, $message_hash, $hash_name, 'pss', $saltlen);

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 is_private

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

=head2 size

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

=head2 key2hash

 my $hash = $pk->key2hash;

 # returns hash like this (or undef if no key loaded):
 {
   type => 1,   # integer: 1 .. private, 0 .. public
   size => 256, # integer: key size in bytes
   # all the rest are hex strings
   e  => "10001", #public exponent
   d  => "9ED5C3D3F866E06957CA0E9478A273C39BBDA4EEAC5B...", #private exponent
   N  => "D0A5CCCAE03DF9C2F5C4C8C0CE840D62CDE279990DC6...", #modulus
   p  => "D3EF0028FFAB508E2773C659E428A80FB0E9211346B4...", #p factor of N
   q  => "FC07E46B163CAB6A83B8E467D169534B2077DCDEECAE...", #q factor of N
   qP => "88C6D406F833DF73C8B734548E0385261AD51F4187CF...", #1/q mod p CRT param
   dP => "486F142FEF0A1F53269AC43D2EE4D263E2841B60DA36...", #d mod (p - 1) CRT param
   dQ => "4597284B2968B72C4212DB7E8F24360B987B80514DA9...", #d mod (q - 1) CRT param
 }

=head1 FUNCTIONS

=head2 rsa_encrypt

RSA based encryption. See method L</encrypt> below.

 my $ct = rsa_encrypt($pub_key_filename, $message);
 #or
 my $ct = rsa_encrypt(\$buffer_containing_pub_key, $message);
 #or
 my $ct = rsa_encrypt($pub_key, $message, $padding);
 #or
 my $ct = rsa_encrypt($pub_key, $message, 'oaep', $hash_name, $lparam);

 # $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none' (INSECURE)
 # $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $lparam (only for oaep) ..... DEFAULT is empty string

=head2 rsa_decrypt

RSA based decryption. See method L</decrypt> below.

 my $pt = rsa_decrypt($priv_key_filename, $ciphertext);
 #or
 my $pt = rsa_decrypt(\$buffer_containing_priv_key, $ciphertext);
 #or
 my $pt = rsa_decrypt($priv_key, $ciphertext, $padding);
 #or
 my $pt = rsa_decrypt($priv_key, $ciphertext, 'oaep', $hash_name, $lparam);

 # $padding .................... 'oaep' (DEFAULT), 'v1.5' or 'none' (INSECURE)
 # $hash_name (only for oaep) .. 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $lparam (only for oaep) ..... DEFAULT is empty string

=head2 rsa_sign_message

Generate RSA signature. See method L</sign_message> below.

 my $sig = rsa_sign_message($priv_key_filename, $message);
 #or
 my $sig = rsa_sign_message(\$buffer_containing_priv_key, $message);
 #or
 my $sig = rsa_sign_message($priv_key, $message, $hash_name);
 #or
 my $sig = rsa_sign_message($priv_key, $message, $hash_name, $padding);
 #or
 my $sig = rsa_sign_message($priv_key, $message, $hash_name, 'pss', $saltlen);

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 rsa_verify_message

Verify RSA signature. See method L</verify_message> below.

 rsa_verify_message($pub_key_filename, $signature, $message) or die "ERROR";
 #or
 rsa_verify_message(\$buffer_containing_pub_key, $signature, $message) or die "ERROR";
 #or
 rsa_verify_message($pub_key, $signature, $message, $hash_name) or die "ERROR";
 #or
 rsa_verify_message($pub_key, $signature, $message, $hash_name, $padding) or die "ERROR";
 #or
 rsa_verify_message($pub_key, $signature, $message, $hash_name, 'pss', $saltlen) or die "ERROR";

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 rsa_sign_hash

Generate RSA signature. See method L</sign_hash> below.

 my $sig = rsa_sign_hash($priv_key_filename, $message_hash);
 #or
 my $sig = rsa_sign_hash(\$buffer_containing_priv_key, $message_hash);
 #or
 my $sig = rsa_sign_hash($priv_key, $message_hash, $hash_name);
 #or
 my $sig = rsa_sign_hash($priv_key, $message_hash, $hash_name, $padding);
 #or
 my $sig = rsa_sign_hash($priv_key, $message_hash, $hash_name, 'pss', $saltlen);

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head2 rsa_verify_hash

Verify RSA signature. See method L</verify_hash> below.

 rsa_verify_hash($pub_key_filename, $signature, $message_hash) or die "ERROR";
 #or
 rsa_verify_hash(\$buffer_containing_pub_key, $signature, $message_hash) or die "ERROR";
 #or
 rsa_verify_hash($pub_key, $signature, $message_hash, $hash_name) or die "ERROR";
 #or
 rsa_verify_hash($pub_key, $signature, $message_hash, $hash_name, $padding) or die "ERROR";
 #or
 rsa_verify_hash($pub_key, $signature, $message_hash, $hash_name, 'pss', $saltlen) or die "ERROR";

 # $hash_name ............... 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................. 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (only for pss) .. DEFAULT is 12

=head1 OpenSSL interoperability

 ### let's have:
 # RSA private key in PEM format - rsakey.priv.pem
 # RSA public key in PEM format  - rsakey.pub.pem
 # data file to be signed or encrypted - input.data

=head2 Encrypt by OpenSSL, decrypt by Crypt::PK::RSA

Create encrypted file (from commandline):

 openssl rsautl -encrypt -inkey rsakey.pub.pem -pubin -out input.encrypted.rsa -in input.data

Decrypt file (Perl code):

  use Crypt::PK::RSA;
  use File::Slurp 'read_file';

  my $pkrsa = Crypt::PK::RSA->new("rsakey.priv.pem");
  my $encfile = read_file("input.encrypted.rsa", binmode=>':raw');
  my $plaintext = $pkrsa->decrypt($encfile, 'v1.5');
  print $plaintext;

=head2 Encrypt by Crypt::PK::RSA, decrypt by OpenSSL

Create encrypted file (Perl code):

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

  my $plaintext = 'secret message';
  my $pkrsa = Crypt::PK::RSA->new("rsakey.pub.pem");
  my $encrypted = $pkrsa->encrypt($plaintext, 'v1.5');
  write_file("input.encrypted.rsa", {binmode=>':raw'}, $encrypted);

Decrypt file (from commandline):

 openssl rsautl -decrypt -inkey rsakey.priv.pem -in input.encrypted.rsa

=head2 Sign by OpenSSL, verify by Crypt::PK::RSA

Create signature (from commandline):

 openssl dgst -sha1 -sign rsakey.priv.pem -out input.sha1-rsa.sig input.data

Verify signature (Perl code):

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

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

=head2 Sign by Crypt::PK::RSA, verify by OpenSSL

Create signature (Perl code):

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

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

Verify signature (from commandline):

 openssl dgst -sha1 -verify rsakey.pub.pem -signature input.sha1-rsa.sig input.data

=head2 Keys generated by Crypt::PK::RSA

Generate keys (Perl code):

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

 my $pkrsa = Crypt::PK::RSA->new;
 $pkrsa->generate_key(256, 65537);
 write_file("rsakey.pub.der",  {binmode=>':raw'}, $pkrsa->export_key_der('public'));
 write_file("rsakey.priv.der", {binmode=>':raw'}, $pkrsa->export_key_der('private'));
 write_file("rsakey.pub.pem",  $pkrsa->export_key_pem('public_x509'));
 write_file("rsakey.priv.pem", $pkrsa->export_key_pem('private'));
 write_file("rsakey-passwd.priv.pem", $pkrsa->export_key_pem('private', 'secret'));

Use keys by OpenSSL:

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

=head2 Keys generated by OpenSSL

Generate keys:

 openssl genrsa -out rsakey.priv.pem 1024
 openssl rsa -in rsakey.priv.pem -out rsakey.priv.der -outform der
 openssl rsa -in rsakey.priv.pem -out rsakey.pub.pem -pubout
 openssl rsa -in rsakey.priv.pem -out rsakey.pub.der -outform der -pubout
 openssl rsa -in rsakey.priv.pem -passout pass:secret -des3 -out rsakey-passwd.priv.pem

Load keys (Perl code):

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

 my $pkrsa = Crypt::PK::RSA->new;
 $pkrsa->import_key("rsakey.pub.der");
 $pkrsa->import_key("rsakey.priv.der");
 $pkrsa->import_key("rsakey.pub.pem");
 $pkrsa->import_key("rsakey.priv.pem");
 $pkrsa->import_key("rsakey-passwd.priv.pem", "secret");

=head1 SEE ALSO

=over

=item * L<https://en.wikipedia.org/wiki/RSA_%28algorithm%29|https://en.wikipedia.org/wiki/RSA_%28algorithm%29>

=back
