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Duplicate openssl smime -decrypt -in some_file.dat.enc -binary -inform DER -inkey private.key -out some_file.dat

See more OpenSSL Examples

Demonstrates how to decrypt binary DER that was encrypted using the following openssl command:
openssl smime -encrypt -binary -aes-256-cbc -in some_file.dat -out some_file.dat.enc -outform DER cert.crt

Chilkat PowerShell Downloads

PowerShell
Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

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

# Duplicates the following openssl command:
# openssl smime -decrypt -in hello.txt.enc -binary -inform DER -inkey private.key -out hello.txt

$cert = New-Object Chilkat.Cert
$success = $cert.LoadFromFile("qa_data/openssl/EE.cer")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

$bd = New-Object Chilkat.BinData
$success = $bd.LoadFile("qa_data/openssl/EE.key")
# Assuming success..

$privKey = New-Object Chilkat.PrivateKey
$success = $privKey.LoadAnyFormat($bd,"")
if ($success -eq $false) {
    $($privKey.LastErrorText)
    exit
}

$crypt = New-Object Chilkat.Crypt2
$success = $crypt.SetDecryptCert2($cert,$privKey)
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

$crypt.CryptAlgorithm = "PKI"
$success = $crypt.CkDecryptFile("qa_data/openssl/hello.txt.enc","qa_output/hello.txt")
if ($success -eq $false) {
    $($crypt.LastErrorText)
    exit
}

$("Success.")