NAME

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

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";

DESCRIPTION

The module provides a full featured RSA implementation.

METHODS

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);

generate_key

Uses Yarrow-based cryptographically strong random number generator seeded with random data taken from "/dev/random" (UNIX) or "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)

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);

RSA public keys

RSA private keys

RSA private keys in password protected PEM format

PKCS#8 encoded private keys

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

RSA public key from X509 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 <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",
 }

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

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

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 '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

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://tools.ietf.org/html/rfc7638>.

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

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

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

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

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

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

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

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

 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
 }

FUNCTIONS

rsa_encrypt

RSA based encryption. See method "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

rsa_decrypt

RSA based decryption. See method "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

rsa_sign_message

Generate RSA signature. See method "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

rsa_verify_message

Verify RSA signature. See method "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

rsa_sign_hash

Generate RSA signature. See method "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

rsa_verify_hash

Verify RSA signature. See method "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

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");