(PowerBuilder) JWE using A256GCMKW

This example demonstrates creating a JCE with AES GCM key wrap.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
integer li_Success
string ls_Plaintext
oleobject loo_Jwe
oleobject loo_JweProtHdr
oleobject loo_Prng
string ls_AesWrappingKey
string ls_StrJwe
oleobject loo_Jwe2
string ls_OriginalPlaintext

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

ls_Plaintext = "My text to enrypt"

loo_Jwe = create oleobject
// Use "Chilkat_9_5_0.Jwe" for versions of Chilkat < 10.0.0
li_rc = loo_Jwe.ConnectToNewObject("Chilkat.Jwe")
if li_rc < 0 then
    destroy loo_Jwe
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// First build the JWE Protected Header: 

//         {
//             "alg": "A256GCMKW",
//             "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
//             "tag": "kfPduVQ3T3H6vnewt--ksw",
//             "iv": "KkYT0GX_2jHlfqN_",
//             "enc": "A128CBC-HS256"
//         }

loo_JweProtHdr = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_JweProtHdr.ConnectToNewObject("Chilkat.JsonObject")

loo_JweProtHdr.AppendString("alg","A256GCMKW")
// kid is optional
loo_JweProtHdr.AppendString("kid","18ec08e1-bfa9-4d95-b205-2b4dd1d4321d")
// tag is optional
loo_JweProtHdr.AppendString("tag","kfPduVQ3T3H6vnewt--ksw")
loo_JweProtHdr.AppendString("enc","A256GCM")
// the iv should be 16 random chars.
loo_Prng = create oleobject
// Use "Chilkat_9_5_0.Prng" for versions of Chilkat < 10.0.0
li_rc = loo_Prng.ConnectToNewObject("Chilkat.Prng")

loo_JweProtHdr.AppendString("iv",loo_Prng.RandomString(16,1,1,1))
loo_Jwe.SetProtectedHeader(loo_JweProtHdr)

Write-Debug "JWE Protected Header: " + loo_JweProtHdr.Emit()
Write-Debug "--"

// Given that we have 256-bit AES, our key should be 32 bytes.
// The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
// ascii chars directly as the key.
ls_AesWrappingKey = "2baf4f730f5e4542b428593ef9cceb0e"
loo_Jwe.SetWrappingKey(0,ls_AesWrappingKey,"ascii")

// Encrypt and return the JWE:
ls_StrJwe = loo_Jwe.Encrypt(ls_Plaintext,"utf-8")
if loo_Jwe.LastMethodSuccess <> 1 then
    Write-Debug loo_Jwe.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_Prng
    return
end if

// Show the JWE we just created:
Write-Debug ls_StrJwe

// Decrypt the JWE that was just produced.
// 1) Load the JWE.
// 2) Set the AES wrapping key.
// 3) Decrypt.
loo_Jwe2 = create oleobject
// Use "Chilkat_9_5_0.Jwe" for versions of Chilkat < 10.0.0
li_rc = loo_Jwe2.ConnectToNewObject("Chilkat.Jwe")

li_Success = loo_Jwe2.LoadJwe(ls_StrJwe)
if li_Success <> 1 then
    Write-Debug loo_Jwe2.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_Prng
    destroy loo_Jwe2
    return
end if

// Set the AES wrap key.  Important to use "ascii"
loo_Jwe2.SetWrappingKey(0,ls_AesWrappingKey,"ascii")

// Decrypt.
ls_OriginalPlaintext = loo_Jwe2.Decrypt(0,"utf-8")
if loo_Jwe2.LastMethodSuccess <> 1 then
    Write-Debug loo_Jwe2.LastErrorText
    destroy loo_Jwe
    destroy loo_JweProtHdr
    destroy loo_Prng
    destroy loo_Jwe2
    return
end if

Write-Debug "original text: "
Write-Debug ls_OriginalPlaintext


destroy loo_Jwe
destroy loo_JweProtHdr
destroy loo_Prng
destroy loo_Jwe2