Xbase++ Requires Chilkat v11.0.0+

Decrypt S/MIME and Verify S/MIME Signatures

See more MIME Examples

_LANGUAGE_ example to decrypt S/MIME and verify S/MIME signatures. The S/MIME is unwrapped to get the original MIME prior to signing/encrypting. Xbase++

LOCAL nSuccess
LOCAL oMime
LOCAL nIsEncrypted
LOCAL nIsSigned
LOCAL oSignerCert
LOCAL oDecryptCert

nSuccess := 0

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

oMime := CreateObject("Chilkat.Mime")

//  Load an S/MIME message from a file:
nSuccess := oMime:LoadMimeFile("signedMime.txt")
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
ENDIF

//  The ContainsEncryptedParts/ContainsSignedParts methods
//  can be called to determine if the MIME is encrypted and/or signed:
nIsEncrypted := oMime:ContainsEncryptedParts()
nIsSigned := oMime:ContainsSignedParts()

//  We don't want the "unwrap extras".  You'll see what those
//  are in a few moments...
oMime:UnwrapExtras := 0

//  To verify the signature, call UnwrapSecurity.  This will
//  verify the signature(s) and decrypt the S/MIME and restore
//  the MIME to the unsigned/unencrypted state.
//  The results of what was found are present in the MIME object's
//  properties, as well as extra header fields that are added
//  to the unwrapped MIME.
nSuccess := oMime:UnwrapSecurity()
IF (nSuccess != 1)
    //  UnwrapSecurity returns 1 if all signatures were
    //  verified and all parts decrypted.
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
ENDIF

//  The mime.UnwrapExtras property controls whether or not
//  these additional fields are added to the unwrapped MIME:
//  
//  X-NumPartsSigned: 1
//  X-SignaturesValid: yes
//  X-NumPartsEncrypted: 1
//  X-Decrypted: no
//  
//  The X-NumPartsSigned/X-SignaturesValid headers are added
//  if the MIME was signed.  
//  
//  The X-NumPartsEncrypted/X-Decrypted headers are added
//  if the MIME was encrypted.
//  

//  If the MIME was signed, get the certificate used for signing.
IF (nIsSigned == 1)
    oSignerCert := CreateObject("Chilkat.Cert")

    //  The NumSignerCerts property indicates how many certificates
    //  were used for signing.  This example will assume the value is 1.
    //  To get the 1st signer cert, call LastSignerCert with an index of 0:
    nSuccess := oMime:LastSignerCert(0, oSignerCert)
    IF (nSuccess == 1)
        ? "**** Signer Cert: " + oSignerCert:SubjectCN
    ENDIF

ENDIF

//  If the MIME was encrypted, get the certificate used for decryption
IF (nIsEncrypted == 1)
    //  The NumDecryptCerts property indicates how many certificates
    //  were used for decrypting.  This example will assume the value is 1.
    //  To get the 1st decrypt cert, call LastDecryptCert with an index of 0:
    oDecryptCert := CreateObject("Chilkat.Cert")
    nSuccess := oMime:LastDecryptCert(0, oDecryptCert)
    IF (nSuccess == 1)
        ? "**** Decrypt Cert: " + oDecryptCert:SubjectCN
    ENDIF

ENDIF

//  Display the unwrapped MIME:
? oMime:GetMime()

//  Save the unwrapped MIME to a file:
nSuccess := oMime:SaveMime("unwrappedMime.txt")

oMime:destroy()
oSignerCert:destroy()
oDecryptCert:destroy()