(CkPython) RSAES-OAEP Encrypt String with AES-128 Content Encryption and SHA256

Encrypts a string using RSAES-OAEP with SHA256 and AES-128 content encryption to produce PKCS7 output (base64 encoded).

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat Python Downloads install with pip pip3 install chilkat or download... Python Module for Windows, MacOS, Linux, Alpine Linux, Solaris

import sys
import chilkat

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

# First build a string to be encrypted
sb = chilkat.CkStringBuilder()
i = 1
while i < 25 :
    sb.AppendInt(i)
    sb.Append(" the quick brown fox jumped over the lazy dog.\r\n")
    i = i + 1

print(sb.getAsString())

# The string to be encrypted looks like this:

# 1 the quick brown fox jumped over the lazy dog.
# 2 the quick brown fox jumped over the lazy dog.
# 3 the quick brown fox jumped over the lazy dog.
# 4 the quick brown fox jumped over the lazy dog.
# 5 the quick brown fox jumped over the lazy dog.
# 6 the quick brown fox jumped over the lazy dog.
# ...

# Load a digital certificate. 
# We don't need the private key for encryption.
# Only the public key is needed (which is included in a certificate).
cert = chilkat.CkCert()
success = cert.LoadFromFile("qa_data/rsaes-oaep/cert.pem")
if (success != True):
    print(cert.lastErrorText())
    sys.exit()

crypt = chilkat.CkCrypt2()

# Tell the crypt object to use the certificate.
crypt.SetEncryptCert(cert)

# Indicate that we want PKI encryption (i.e. public-key infrastructure)
# to produce a CMS message (Cryptographic Message Syntax/PKCS7),
# that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
# bulk encryption.
crypt.put_CryptAlgorithm("pki")
crypt.put_Pkcs7CryptAlg("aes")
crypt.put_KeyLength(128)
crypt.put_OaepHash("sha256")
crypt.put_OaepPadding(True)

# Also, don't forget to be specific about the character encoding (byte representation) of the
# string to be encrypted.
crypt.put_Charset("utf-8")

# Now indicate that the PKCS7 output is to be returned in the base64 encoding.
crypt.put_EncodingMode("base64")

base64Pkcs7 = crypt.encryptStringENC(sb.getAsString())
if (crypt.get_LastMethodSuccess() != True):
    print(crypt.lastErrorText())
    sys.exit()

# Show the output
print(base64Pkcs7)

# This base64 can be copy-and-pasted into the form at http://lapo.it/asn1js/
# to verify that all the chosen algorithms were indeed used.

print("OK.")