B4X

Convert Java KeyStore to PKCS12 / PFX

See more Java KeyStore (JKS) Examples

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).

B4X

Dim success As Boolean = False

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

Dim jks As ChilkatJavaKeyStore
jks.Initialize

Dim jksPassword As String = "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.
success = jks.LoadFile(jksPassword, "/someDir/keyStore.jks")
If success <> True Then
    Log(jks.LastErrorText)
    Return
End If


'  To convert, we'll access the private key entries
'  from the JKS, add each to the PKCS12, and then save the PKCS12.
Dim pkcs12 As ChilkatPfx
pkcs12.Initialize

Dim numPrivateKeys As Int = jks.NumPrivateKeys
Dim i As Int

Dim privKey As ChilkatPrivateKey
Dim certChain As ChilkatCertChain

'  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.
i = 0
Do While i < numPrivateKeys
    privKey = jks.GetPrivateKey(jksPassword, i)
    Log(jks.GetPrivateKeyAlias(i))
    certChain = jks.GetCertChain(i)

    '  Add the private key and it's associated certificate chain to the PKCS12.
    success = pkcs12.AddPrivateKey(privKey, certChain)
    If success <> True Then
        Log(pkcs12.LastErrorText)


        Return
    End If




    i = i + 1
Loop

'  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.)
Dim pkcs12Password As String = "myNewPassword"
success = pkcs12.ToFile(pkcs12Password, "/pkcs12_files/myPfx.p12")
If success <> True Then
    Log(pkcs12.LastErrorText)
Else
    Log("Successfully saved to PKCS12 format.")
End If