Xbase++

Encrypt a file to a PKCS7 encrypted message using multiple certificates from different users

See more Encryption Examples

Demonstrates how to encrypt a file to a PKCS7 encrypted message using multiple certificates from different users. Any one of the users can decrypt using his/her own certificate + private key.

Note: When doing public key encryption, it is the public key that is used to encrypt. The private key is required for decryption.

Xbase++

LOCAL nSuccess
LOCAL oCrypt
LOCAL oCert1
LOCAL oCert2
LOCAL oCert3
LOCAL oFileData

nSuccess := 0

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

oCrypt := CreateObject("Chilkat.Crypt2")

//  Tell the crypt object to use 3 certificates.
//  Do this by calling AddEncryptCert for each certificate.

//  Load a digital certificate. 
//  We don't need the private key for encryption.
//  Only the public key is needed (which is included in a certificate).
oCert1 := CreateObject("Chilkat.Cert")
nSuccess := oCert1:LoadFromFile("qa_data/user1/cert_user1.pem")
//  Assume success for the example, but make sure your application checks for success/failure...
oCrypt:AddEncryptCert(oCert1)

oCert2 := CreateObject("Chilkat.Cert")
nSuccess := oCert2:LoadFromFile("qa_data/user2/cert_user2.pem")
oCrypt:AddEncryptCert(oCert2)

oCert3 := CreateObject("Chilkat.Cert")
nSuccess := oCert3:LoadFromFile("qa_data/user3/cert_user3.pem")
oCrypt:AddEncryptCert(oCert3)

//  Indicate that we want PKI encryption (i.e. public-key infrastructure)
//  to produce a CMS message (Cryptographic Message Syntax/PKCS7),
//  that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
//  bulk encryption.
oCrypt:CryptAlgorithm := "pki"
oCrypt:Pkcs7CryptAlg := "aes"
oCrypt:KeyLength := 128
oCrypt:OaepHash := "sha256"
oCrypt:OaepPadding := 1

//  Load the file to be encrypted...
oFileData := CreateObject("Chilkat.BinData")
nSuccess := oFileData:LoadFile("qa_data/jpg/penguins.jpg")
//  Your app should check for success/failure..

//  Encrypt the data.  The contents of the fileData object are replaced with the PKCS7 encrypted message.
nSuccess := oCrypt:EncryptBd(oFileData)
IF (nSuccess != 1)
    ? oCrypt:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oCert2:destroy()
    oCert3:destroy()
    oFileData:destroy()
    RETURN
ENDIF

//  Save the PKCS7 encrypted message to a file..
nSuccess := oFileData:WriteFile("qa_output/pkcs7_encrypted.p7")

//  Now indicate that the PKCS7 output is to be returned in the base64 encoding.
oCrypt:EncodingMode := "base64"

? "OK."

oCrypt:destroy()
oCert1:destroy()
oCert2:destroy()
oCert3:destroy()
oFileData:destroy()