Tcl

Export an Encrypted PKCS #8 Private Key as PEM

Demonstrates the Chilkat PrivateKey.GetPkcs8EncryptedPem method, which exports the key as password-protected PKCS #8 PEM (-----BEGIN ENCRYPTED PRIVATE KEY-----). The only argument is the password; the cipher is selected by the Pkcs8EncryptAlg property.

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 safe way to export a key for storage or transfer — the private material is encrypted under a passphrase, so a leaked file is not immediately usable. It is the format to reach for whenever a key leaves your process. Control the encryption cipher with Pkcs8EncryptAlg, and source the password securely rather than hard-coding it.

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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 as password-protected PKCS #8 PEM ("-----BEGIN ENCRYPTED PRIVATE KEY-----").  The
#  encryption cipher is selected by the Pkcs8EncryptAlg property.
set pem [CkPrivateKey_getPkcs8EncryptedPem $privKey $password]
if {[CkPrivateKey_get_LastMethodSuccess $privKey] == 0} then {
    puts [CkPrivateKey_lastErrorText $privKey]
    delete_CkPrivateKey $privKey
    exit
}

puts "$pem"

delete_CkPrivateKey $privKey