Tcl

Export a Private Key as DER into a BinData

Demonstrates the Chilkat PrivateKey.GetPkcsBd method, which exports the key as DER into a BinData. The first argument selects PKCS #1 (true) versus PKCS #8 (false), the second is the password (empty for unencrypted), and the third is the BinData that receives the bytes.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the in-memory binary export — the raw DER bytes land in a BinData ready to hash, encrypt, or hand to another API without a temporary file. One method covers several cases: the boolean picks the traditional (PKCS #1) versus modern (PKCS #8) structure, and a nonempty password produces an encrypted PKCS #8 export (with the cipher from Pkcs8EncryptAlg). Source any password securely.

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Tcl


load ./chilkat.dll

set success 0

#  Load a private key to export.
set privKey [new_CkPrivateKey]

set success [CkPrivateKey_LoadPemFile $privKey "qa_data/private.pem"]
if {$success == 0} then {
    puts [CkPrivateKey_lastErrorText $privKey]
    delete_CkPrivateKey $privKey
    exit
}

#  The key password is not hard-coded in a real application; obtain it from an interactive
#  prompt, environment variable, or a secrets vault.
set password "myKeyPassword"

#  Export the key as DER into a BinData.  The 1st argument selects PKCS #1 (1) versus PKCS #8
#  (0); the 2nd is the password (empty string for an unencrypted export); the 3rd is the
#  BinData that receives the DER bytes.
set usePkcs1 0
set bd [new_CkBinData]

set success [CkPrivateKey_GetPkcsBd $privKey $usePkcs1 $password $bd]
if {$success == 0} then {
    puts [CkPrivateKey_lastErrorText $privKey]
    delete_CkPrivateKey $privKey
    delete_CkBinData $bd
    exit
}

puts "Exported [CkBinData_get_NumBytes $bd] DER bytes."

delete_CkPrivateKey $privKey
delete_CkBinData $bd