(Xojo Plugin) Encrypt File to PKCS7 .p7m

Xojo Plugin 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Dim crypt As New Chilkat.Crypt2

// 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.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.Pkcs7CryptAlg = "aes"
crypt.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
Dim encryptCert As New Chilkat.Cert
Dim success As Boolean
success = encryptCert.LoadFromFile("/Users/chilkat/testData/cer/acme.cer")
If (success <> True) Then
    System.DebugLog(encryptCert.LastErrorText)
    Return
End If

// 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.
Dim inFile As String
inFile = "/Users/chilkat/testData/pdf/sample.pdf"
Dim outFile As String
outFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m"
success = crypt.CkEncryptFile(inFile,outFile)
If (success <> True) Then
    System.DebugLog(crypt.LastErrorText)
    Return
End If

// For demonstration purposes, a different instance of the object will be used
// for decryption.
Dim decrypt As New Chilkat.Crypt2

// 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.
Dim pfxFilename As String
pfxFilename = "/Users/chilkat/testData/pfx/acme.pfx"
Dim pfxPassword As String
pfxPassword = "secret"

// Tell the component to look in the PFX file for certs and private keys.
success = decrypt.AddPfxSourceFile(pfxFilename,pfxPassword)
If (success <> True) Then
    System.DebugLog(decrypt.LastErrorText)
    Return
End If

// Tell the decrypt object that PKI (public key encryption) is to be used
// for decryptiong.
decrypt.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 = False) Then
    System.DebugLog(decrypt.LastErrorText)
    Return
End If

System.DebugLog("Success!")