AutoIt
openssl smime -encrypt -des3 -in <file> <pem file>

OpenSSL SMIME encrypt file using PEM containing a certificate.
Chilkat AutoIt Downloads

AutoIt
Local $bSuccess = False

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

; Load the cert from a PEM file.

$oPem = ObjCreate("Chilkat.Pem")
; Our particular PEM was not encrypted, so we pass an empty password.
; Also, a private key is not needed for encryption.  The PEM used to test this example
; happens to have a private key, but it's not actually used.
$bSuccess = $oPem.LoadPemFile("qa_data/openssl/rsaCertAndKey.pem","")
If ($bSuccess = False) Then
    ConsoleWrite($oPem.LastErrorText & @CRLF)
    Exit
EndIf

If ($oPem.NumCerts = 0) Then
    ConsoleWrite("PEM does not contain any certificates." & @CRLF)
    Exit
EndIf

Local $oCert = $oPem.GetCert(0)
If ($oPem.LastMethodSuccess = False) Then
    ConsoleWrite($oPem.LastErrorText & @CRLF)
    Exit
EndIf

; -------------------------------------------------------------------------------------
; Duplicate this OpenSSL command:   openssl smime -encrypt -des3 -in <file> <pem file>
; -------------------------------------------------------------------------------------
$oCrypt = ObjCreate("Chilkat.Crypt2")
$bSuccess = $oCrypt.SetEncryptCert($oCert)
If ($bSuccess = False) Then
    ConsoleWrite($oCrypt.LastErrorText & @CRLF)

    Exit
EndIf

$oCrypt.CryptAlgorithm = "PKI"
$oCrypt.Pkcs7CryptAlg = "3des"
$oCrypt.KeyLength = 168

; Load the file to be encrypted.
$oBd = ObjCreate("Chilkat.BinData")
$bSuccess = $oBd.LoadFile("qa_data/openssl/hello.txt")
If ($bSuccess = False) Then
    ConsoleWrite("Failed to load the input file." & @CRLF)
    Exit
EndIf

; Encrypt.
$bSuccess = $oCrypt.EncryptBd($oBd)
If ($bSuccess = False) Then
    ConsoleWrite($oCrypt.LastErrorText & @CRLF)
    Exit
EndIf

; The openssl smime -encrypt command produces encrypte MIME such as this:

; MIME-Version: 1.0
; Content-Disposition: attachment; filename="smime.p7m"
; Content-Type: application/x-pkcs7-mime; smime-type=enveloped-data; name="smime.p7m"
; Content-Transfer-Encoding: base64
; 
; MIICzwYJKoZIhvcNAQcDoIICwDCCArwCAQAxggF8MIIBeAIBADBgMEoxCzAJBgNVBAYTAlVTMRYw
; FAYDVQQKEw1MZXQncyBFbmNyeXB0MSMwIQYDVQQDExpMZXQncyBFbmNyeXB0IEF1dGhvcml0eSBY
; MwISA9Nqgb1dH/XTDNeKzN1nR85iMA0GCSqGSIb3DQEBAQUABIIBAIQqPexjxWovgxwKV/r3HL/U
; EP9Yozvz5hBeX5VvRZjKSi4FRw5wapElPK+4FB82hiAR9Mi3c16PvPSVkJv3l78Mv5uaaOs/OmUz
; mIHFB6Z+l2E52BDmUVWJZTQ09vdWy6+NIRlg2R9Z1NkmZ4BZCJk6mHB/Yx03IaOxK8LnwieDMthM
; SvxbhJnIOISN7k7ofs+/0vTXUpdQ+tlmwyVySMGQ6VMk+z4sqZJ2stacqCPtt/aiSwJ9p0OKmihf
; 3KDJceXJtavIQeA97yz1LqPvle35mmd5sBhV9qQYdTV/KJ+YM5uEZ9BHYbvMJbADFHwKzhcEY3qA
; 7T9acmEsb7NycOIwggE1BgkqhkiG9w0BBwEwFAYIKoZIhvcNAwcECERX/ZoHweSkgIIBEMmCMx49
; zjVAnGqRaBbvzQT1hg0uQSxIJjxMxC+HSuM+eY9oSOsbrw4uIijHKH9NdOpeDsdRzg2z5EBM7AlP
; Ht9DyPW5C2deV6RPX4F8gyExz+JUXrd+3Yb3AKTdpDkTWDmNCeO0r/YSqp518+mfU5hG8e336u51
; HAM44FeknA8oThWsD/wUB1e8vzsatK4UXW/KSu/166V7z+VT86kd+IHa7t60U9Yp0ZXgcM5Pb5Ni
; 69Qc5MKPzom2801H5UR/WjCgsxOIjOj49sKisjRy79skrJzxY5ZG05T0dKn6KC3TjRpIEEeOyhCd
; Nm2Y7dcW8GLMepdhWay5vePmQxmvmhbAtBprIem14NcrYeG6D5wP

; We have the body in bd
; Construct the header and base64 body...
$oSbEncryptedMime = ObjCreate("Chilkat.StringBuilder")

$oSbEncryptedMime.AppendLine("MIME-Version: 1.0",True)
$oSbEncryptedMime.AppendLine("Content-Disposition: attachment; filename=""smime.p7m""",True)
$oSbEncryptedMime.AppendLine("Content-Type: application/x-pkcs7-mime; smime-type=enveloped-data; name=""smime.p7m""",True)
$oSbEncryptedMime.AppendLine("Content-Transfer-Encoding: base64",True)
$oSbEncryptedMime.AppendLine("",True)
$oSbEncryptedMime.AppendLine($oBd.GetEncoded("base64_mime"),True)

; Show the result.
ConsoleWrite($oSbEncryptedMime.GetAsString() & @CRLF)

; or save to a file..
$bSuccess = $oSbEncryptedMime.WriteFile("qa_output/encryptedMime.txt","utf-8",False)