Encrypt File to PKCS7 .p7m

Perl example to public-key encrypt a file creating a PKCS#7 .p7m file as output. Also demonstrates how to decrypt the .p7m to recover the original file.

 Chilkat Perl Module Downloads for Windows, Linux, and MAC OS X

use chilkat();

$crypt = new chilkat::CkCrypt2();

#  Any string argument automatically begins the 30-day trial.
$success = $crypt->UnlockComponent("30-day trial");
if ($success != 1) {
    print $crypt->lastErrorText() . "\r\n";
    exit;
}

#  Indicate the public-key encryption is to be used.
#  Do this by setting the encryption algorithm equal
#  to "PKI" (an acroynm for public-key infrastructure).
$crypt->put_CryptAlgorithm("PKI");

#  Indicate the inner symmetric encryption algorithm to be used.
#  possible values are "aes", "des", "3des", and "rc2".
#  For this example, we'll use 256-bit AES encryption.
$crypt->put_Pkcs7CryptAlg("aes");
$crypt->put_KeyLength(256);

#  To encrypt, only a certificate w/ public key is needed.
#  (The certificate w/ private key is required for decryption.)

#  The LoadFromFile method can load virtually any certificate format:
#  1. DER encoded binary X.509 (.CER)
#  2. Base-64 encoded X.509 (.CER)
#  3. Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)
#  4. PEM format
$encryptCert = new chilkat::CkCert();
$success = $encryptCert->LoadFromFile("/Users/chilkat/testData/cer/acme.cer");
if ($success != 1) {
    print $encryptCert->lastErrorText() . "\r\n";
    exit;
}

#  Tell the crypt object to use the certificate for encrypting:
$crypt->AddEncryptCert($encryptCert);

#  Encrypt a file, producing a .p7m as output.
#  The input file is unchanged, the output .p7m contains the encrypted
#  contents of the input file.
$inFile = "/Users/chilkat/testData/pdf/sample.pdf";
$outFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m";
$success = $crypt->CkEncryptFile($inFile,$outFile);
if ($success != 1) {
    print $crypt->lastErrorText() . "\r\n";
    exit;
}

#  For demonstration purposes, a different instance of the object will be used
#  for decryption.
$decrypt = new chilkat::CkCrypt2();

#  To decrypt, the certificate w/ private key is required.  A PFX (also known
#  as PKCS#12) is a common secure container for certs and private keys.
$pfxFilename = "/Users/chilkat/testData/pfx/acme.pfx";
$pfxPassword = "secret";

#  Tell the component to look in the PFX file for certs and private keys.
$success = $decrypt->AddPfxSourceFile($pfxFilename,$pfxPassword);
if ($success != 1) {
    print $decrypt->lastErrorText() . "\r\n";
    exit;
}

#  Tell the decrypt object that PKI (public key encryption) is to be used
#  for decryptiong.
$decrypt->put_CryptAlgorithm("PKI");
#  There is no need to set the Pkcs7Alg or KeyLength because this information
#  is contained within the .p7m

#  Decrypt the .p7m
$inFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m";
$outFile = "/Users/chilkat/testData/pdf/recovered.pdf";
$success = $decrypt->CkDecryptFile($inFile,$outFile);
if ($success == 0) {
    print $decrypt->lastErrorText() . "\r\n";
    exit;
}

print "Success!" . "\n";