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CkPython

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 CkPython Downloads

CkPython
import sys
import chilkat

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 = chilkat.CkCert()
success = cert.LoadFromFile("qa_data/openssl/EE.cer")
if (success == False):
    print(cert.lastErrorText())
    sys.exit()

bd = chilkat.CkBinData()
success = bd.LoadFile("qa_data/openssl/EE.key")
# Assuming success..

privKey = chilkat.CkPrivateKey()
success = privKey.LoadAnyFormat(bd,"")
if (success == False):
    print(privKey.lastErrorText())
    sys.exit()

crypt = chilkat.CkCrypt2()
success = crypt.SetDecryptCert2(cert,privKey)
if (success == False):
    print(crypt.lastErrorText())
    sys.exit()

crypt.put_CryptAlgorithm("PKI")
success = crypt.CkDecryptFile("qa_data/openssl/hello.txt.enc","qa_output/hello.txt")
if (success == False):
    print(crypt.lastErrorText())
    sys.exit()

print("Success.")