Crypt::PK::RSA(3)

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

SYNOPSIS
 ### OO interface

 my $message = 'hello world';
 my $private_key = Crypt::PK::RSA->new();
 $private_key->generate_key(256, 65537);

 my $public_der = $private_key->export_key_der('public');
 my $public_key = Crypt::PK::RSA->new(\$public_der);

 my $ciphertext = $public_key->encrypt($message);
 my $plaintext = $private_key->decrypt($ciphertext);

 my $signature = $private_key->sign_message($message);
 $public_key->verify_message($signature, $message) or die "ERROR";

 my $private_der = $private_key->export_key_der('private');
 my $private_pem = $private_key->export_key_pem('private');
 my $public_pem = $public_key->export_key_pem('public');

DESCRIPTION
The module provides a full featured RSA implementation.

Legacy function-style wrappers still exist in code for backwards compatibility, but they are intentionally undocumented.

METHODS

  new
  my $source = Crypt::PK::RSA->new();
  $source->generate_key(256, 65537);

  my $public_der = $source->export_key_der('public');
  my $pub = Crypt::PK::RSA->new(\$public_der);

  my $private_pem = $source->export_key_pem('private', 'secret', 'AES-256-CBC');
  my $priv = Crypt::PK::RSA->new(\$private_pem, 'secret');

Passing $filename or "\$buffer" to "new" is equivalent: both forms immediately import the key material into the new object.

  generate_key
Uses the bundled "chacha20" PRNG via libtomcrypt's "rng_make_prng". Returns the object itself (for chaining).

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

The $size and $e arguments use Perl's usual numeric-to-integer coercion before reaching the XS layer. Pass exact integers; values like 10.9 or "1e2" are coerced rather than rejected.

  import_key
Loads private or public key in DER or PEM format.

  my $source = Crypt::PK::RSA->new();
  $source->generate_key(256, 65537);

  my $public_der = $source->export_key_der('public');
  my $pub = Crypt::PK::RSA->new();
  $pub->import_key(\$public_der);

  my $private_pem = $source->export_key_pem('private', 'secret', 'AES-256-CBC');
  my $priv = Crypt::PK::RSA->new();
  $priv->import_key(\$private_pem, 'secret');

The same method also accepts filenames instead of buffers.

Loading private or public keys from a 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);

•   RSA public keys

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

•   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-----

•   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-----

•   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-----

•   PKCS#8 encrypted private keys - password protected keys (supported since: CryptX-0.062)

     -----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-----

•   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-----

•   SSH public RSA keys

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

•   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 ----

•   RSA private keys in JSON Web Key (JWK) format

    See <https://www.rfc-editor.org/rfc/rfc7517>

     {
       "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",
     }

    BEWARE: For JWK support you need to have JSON module installed.

•   RSA public keys in JSON Web Key (JWK) format

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

    BEWARE: For JWK support you need to have JSON module installed.

  export_key_der
Returns the key as a binary DER-encoded string.

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

  export_key_pem
Returns the key as a PEM-encoded string (ASCII).

 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 'public' uses header and footer lines:

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

With parameter '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)

  export_key_jwk
Since: CryptX-0.022

Returns a JSON string, or a hashref if the optional second argument is true.

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);

BEWARE: For JWK support you need to have JSON module installed.

  export_key_jwk_thumbprint
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 <https://www.rfc-editor.org/rfc/rfc7638>.

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

  encrypt
Returns the ciphertext as a binary string.

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

  decrypt
Returns the plaintext as a binary string.

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

  sign_message
Returns the signature as a binary string.

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

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

For RSASSA-PSS with SHAKE per RFC 8702 <https://www.rfc-editor.org/rfc/rfc8702> use 'SHAKE128' (output 32 bytes, $saltlen = 32) or 'SHAKE256' (output 64 bytes, $saltlen = 64); both the message hash and the internal MGF use SHAKE directly as defined by RFC 8702.

 my $sig = $pk->sign_message($message, 'SHAKE128', 'pss', 32);  # id-RSASSA-PSS-SHAKE128
 my $sig = $pk->sign_message($message, 'SHAKE256', 'pss', 64);  # id-RSASSA-PSS-SHAKE256

  verify_message
Returns 1 if the signature is valid, 0 otherwise.

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

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

  sign_hash
Returns the signature as a binary string.

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

 # $hash_name ................. [string] 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................... [string] 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (pss only) ........ [integer] DEFAULT is 12
 # $mgf_hash_name (pss only) .. [string] MGF hash function name (DEFAULT: the $hash_name value)

  verify_hash
Returns 1 if the signature is valid, 0 otherwise.

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

 # $hash_name ................. [string] 'SHA1' (DEFAULT), 'SHA256' or any other hash supported by Crypt::Digest
 # $padding ................... [string] 'pss' (DEFAULT) or 'v1.5' or 'none' (INSECURE)
 # $saltlen (pss only) ........ [integer] DEFAULT is 12
 # $mgf_hash_name (pss only) .. [string] MGF hash function name (DEFAULT: the $hash_name value)

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

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

  key2hash
Returns a hashref with the key components, or "undef" if no key is loaded.

 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
 }

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

  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 Crypt::Misc 'read_rawfile';

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

  Encrypt by Crypt::PK::RSA, decrypt by OpenSSL
Create encrypted file (Perl code):

  use Crypt::PK::RSA;
  use Crypt::Misc 'write_rawfile';

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

Decrypt file (from commandline):

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

  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 Crypt::Misc 'read_rawfile';

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

  Sign by Crypt::PK::RSA, verify by OpenSSL
Create signature (Perl code):

 use Crypt::PK::RSA;
 use Crypt::Digest 'digest_file';
 use Crypt::Misc 'write_rawfile';

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

Verify signature (from commandline):

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

  Keys generated by Crypt::PK::RSA
Generate keys (Perl code):

 use Crypt::PK::RSA;
 use Crypt::Misc 'write_rawfile';

 my $pkrsa = Crypt::PK::RSA->new;
 $pkrsa->generate_key(256, 65537);
 write_rawfile("rsakey.pub.der",  $pkrsa->export_key_der('public'));
 write_rawfile("rsakey.priv.der", $pkrsa->export_key_der('private'));
 write_rawfile("rsakey.pub.pem",  $pkrsa->export_key_pem('public_x509'));
 write_rawfile("rsakey.priv.pem", $pkrsa->export_key_pem('private'));
 write_rawfile("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

  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;

 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");

SEE ALSO

•   <https://en.wikipedia.org/wiki/RSA_%28algorithm%29>