(Tcl) Create PKCS7 (CMS) EnvelopedData

Encrypt some data to a recipient by creating a PKCS7 (CMS) EnvelopedData structure. The data will be encrypted using a symmetric content-encryption algorithm (e.g., AES), and the randomly generated symmetric key will be encrypted using the recipient’s RSA public key extracted from their X.509 certificate.

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load ./chilkat.dll

set crypt [new_CkCrypt2]

# Specify the encryption to be used.
# "pki" indicates "Public Key Infrastructure" and will create a PKCS7 encrypted (enveloped-data) message.
CkCrypt2_put_CryptAlgorithm $crypt "pki"
CkCrypt2_put_Pkcs7CryptAlg $crypt "aes"
CkCrypt2_put_KeyLength $crypt 256
CkCrypt2_put_OaepHash $crypt "sha256"
CkCrypt2_put_OaepPadding $crypt 1

set cert [new_CkCert]

# Use a certificate found in the Windows certificate store.
set success [CkCert_LoadByCommonName $cert "My Certificate"]
if {$success != 1} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

# Tell the crypt object to use the certificate.
CkCrypt2_SetEncryptCert $crypt $cert

set toBeEncrypted "This string is to be encrypted."

# Get the result in multi-line BASE64 MIME format.
CkCrypt2_put_EncodingMode $crypt "base64_mime"
CkCrypt2_put_Charset $crypt "utf-8"

set result [CkCrypt2_encryptStringENC $crypt $toBeEncrypted]
if {$success != 1} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    delete_CkCert $cert
    exit
}

# -------------------------------------------------------------------------
# See the following example to decrypt what was created in this example
# Decrypt PKCS7 (CMS) EnvelopedData
# -------------------------------------------------------------------------

puts "$result"

# Sample output:

# MIICSgYJKoZIhvcNAQcDoIICOzCCAjcCAQAxggHiMIIB3gIBADCBljCBgTELMAkGA1UEBhMCSVQx
# EDAOBgNVBAgMB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8xFzAVBgNVBAoMDkFj
# dGFsaXMgUy5wLkEuMSwwKgYDVQQDDCNBY3RhbGlzIENsaWVudCBBdXRoZW50aWNhdGlvbiBDQSBH
# MwIQPCWvkSv8oQ7xRmEHJ6TzEDA8BgkqhkiG9w0BAQcwL6APMA0GCWCGSAFlAwQCAQUAoRwwGgYJ
# KoZIhvcNAQEIMA0GCWCGSAFlAwQCAQUABIIBAKqHAPQNSsQoX7B2NH7QyEOWQRsSVs8oCHXmy8f4
# MVZD2er3bvYUCIomxpwbLEAl14qjUIMynahooYGgqip7+4FqL301G+BVjZVfEhHWj+VI1dAWnWuL
# VHlvc/pbQNBWqV8rKVJsNIsuAZkdj4WSwLVKxYkYX43B8fh/g71XN2DTJu7Z/824v48KBmgpQBOT
# 2q7IcDGxNPAFN2p6eavIVGn2LvhEbf/Fszyj+GR5tMcnQP1BOLJ3s3JzUBbvj8hcZrF1Vhl9HnTU
# YQx8G/KdW1mR+Wlhl3BWoK0LYKRTbnTx2BXOs0CY1SXOAdhKr01ZYjA+xW4nGzY0lfXS9QZjh9gw
# TAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBKgQQw0xTbfmnt0zjWHo5SaQIp4AgxTVY9E/Ncqy6t+RM
# 8y4c3Av62/wB8IpPUEmtM2OeuZo=

delete_CkCrypt2 $crypt
delete_CkCert $cert