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, 'SHA256');
 $public_key->verify_message($signature, $message, 'SHA256') 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, INSECURE), '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

BEWARE: The $hash_name default is 'SHA1' only for backward compatibility. SHA-1 is vulnerable to practical collision attacks and is not safe for signing messages whose content may be influenced by an attacker. Always pass an explicit hash name such as 'SHA256'. The same applies to "verify_message", "sign_hash" and "verify_hash".

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, INSECURE), '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, INSECURE), '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, INSECURE), '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 -sha256 -sign rsakey.priv.pem -out input.sha256-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.sha256-rsa.sig");
 my $valid = $pkrsa->verify_hash($signature, digest_file("SHA256", "input.data"), "SHA256", "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("SHA256", "input.data"), "SHA256", "v1.5");
 write_rawfile("input.sha256-rsa.sig", $signature);

Verify signature (from commandline):

 openssl dgst -sha256 -verify rsakey.pub.pem -signature input.sha256-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>