DataFlex

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. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoMime
    Boolean iIsEncrypted
    Boolean iIsSigned
    Variant vSignerCert
    Handle hoSignerCert
    Variant vDecryptCert
    Handle hoDecryptCert
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatMime)) To hoMime
    If (Not(IsComObjectCreated(hoMime))) Begin
        Send CreateComObject of hoMime
    End

    // Load an S/MIME message from a file:
    Get ComLoadMimeFile Of hoMime "signedMime.txt" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoMime To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // The ContainsEncryptedParts/ContainsSignedParts methods
    // can be called to determine if the MIME is encrypted and/or signed:
    Get ComContainsEncryptedParts Of hoMime To iIsEncrypted
    Get ComContainsSignedParts Of hoMime To iIsSigned

    // We don't want the "unwrap extras".  You'll see what those
    // are in a few moments...
    Set ComUnwrapExtras Of hoMime To False

    // 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.
    Get ComUnwrapSecurity Of hoMime To iSuccess
    If (iSuccess <> True) Begin
        // UnwrapSecurity returns True if all signatures were
        // verified and all parts decrypted.
        Get ComLastErrorText Of hoMime To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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 (iIsSigned = True) Begin
        Get Create (RefClass(cComChilkatCert)) To hoSignerCert
        If (Not(IsComObjectCreated(hoSignerCert))) Begin
            Send CreateComObject of hoSignerCert
        End

        // 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:
        Get pvComObject of hoSignerCert to vSignerCert
        Get ComLastSignerCert Of hoMime 0 vSignerCert To iSuccess
        If (iSuccess = True) Begin
            Get ComSubjectCN Of hoSignerCert To sTemp1
            Showln "**** Signer Cert: " sTemp1
        End

    End

    // If the MIME was encrypted, get the certificate used for decryption
    If (iIsEncrypted = True) Begin
        // 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:
        Get Create (RefClass(cComChilkatCert)) To hoDecryptCert
        If (Not(IsComObjectCreated(hoDecryptCert))) Begin
            Send CreateComObject of hoDecryptCert
        End
        Get pvComObject of hoDecryptCert to vDecryptCert
        Get ComLastDecryptCert Of hoMime 0 vDecryptCert To iSuccess
        If (iSuccess = True) Begin
            Get ComSubjectCN Of hoDecryptCert To sTemp1
            Showln "**** Decrypt Cert: " sTemp1
        End

    End

    // Display the unwrapped MIME:
    Get ComGetMime Of hoMime To sTemp1
    Showln sTemp1

    // Save the unwrapped MIME to a file:
    Get ComSaveMime Of hoMime "unwrappedMime.txt" To iSuccess


End_Procedure