(Tcl) Convert Java KeyStore to PKCS12 / PFX

Loads a Java keystore file and saves it as a PKCS12 / PFX. A Java keystore (JKS) can contain two types of entries: (1) trusted root certificates or (2) private keys + cert chains. Usually a JKS will contain all entries of one type or another (and thus a particular JKS serves one purpose or another; meaning that a JKS containing trusted roots is used as a source for verifying pre-trusted roots, and a JKS containing private keys (and cert chains) is used as a secure, encrypted store for private keys).

A PKCS12 / PFX typically contains one or more private keys, along with each private key's certificate chain. Therefore, it typically makes sense to only write the private key entries to a PKCS12 (and the associated certificate chains). If a JKS contains trusted root certificates, it makes more sense to conver it to a PEM file (such as the CA cert bundle in PEM format from mozilla.org).

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load ./chilkat.dll

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

set jks [new_CkJavaKeyStore]

set jksPassword "myJksPassword"

# Load the Java keystore from a file.  The JKS file password is used
# to verify the keyed digest that is found at the very end of the keystore.
# It verifies that the keystore has not been modified.
set success [CkJavaKeyStore_LoadFile $jks $jksPassword "/someDir/keyStore.jks"]
if {$success != 1} then {
    puts [CkJavaKeyStore_lastErrorText $jks]
    delete_CkJavaKeyStore $jks
    exit
}

# To convert, we'll access the private key entries
# from the JKS, add each to the PKCS12, and then save the PKCS12.
set pkcs12 [new_CkPfx]

set numPrivateKeys [CkJavaKeyStore_get_NumPrivateKeys $jks]

# privKey is a CkPrivateKey

# certChain is a CkCertChain

# For each private key entry, get the private key and
# the associated certificate chain.
# Each private key is password protected.  Usually it is the same
# password as used for the keyed digest of the entire JKS.  
# However, this does not have to be.  The password is passed
# here to handle the possibility of each private key requiring
# a different password.
set i 0
while {$i < $numPrivateKeys} {
    set privKey [CkJavaKeyStore_GetPrivateKey $jks $jksPassword $i]
    puts [CkJavaKeyStore_getPrivateKeyAlias $jks $i]
    set certChain [CkJavaKeyStore_GetCertChain $jks $i]

    # Add the private key and it's associated certificate chain to the PKCS12.
    set success [CkPfx_AddPrivateKey $pkcs12 $privKey $certChain]
    if {$success != 1} then {
        puts [CkPfx_lastErrorText $pkcs12]
        delete_CkCertChain $certChain

        delete_CkPrivateKey $privKey

        delete_CkJavaKeyStore $jks
        delete_CkPfx $pkcs12
        exit
    }

    delete_CkCertChain $certChain

    delete_CkPrivateKey $privKey

    set i [expr $i + 1]
}

# Save the PKCS12 / PFX to a file.
# The password can be the same as the JKS password, or something new.
# (With the PKCS12 format, there is a single password for the entire contents
# of the file.  With the JKS format, there is flexibility in allowing each private key
# to have it's own password.)
set pkcs12Password "myNewPassword"
set success [CkPfx_ToFile $pkcs12 $pkcs12Password "/pkcs12_files/myPfx.p12"]
if {$success != 1} then {
    puts [CkPfx_lastErrorText $pkcs12]
} else {
    puts "Successfully saved to PKCS12 format."
}


delete_CkJavaKeyStore $jks
delete_CkPfx $pkcs12