(PowerBuilder) JWE using AES Key Wrap and AES_128_CBC_HMAC_SHA_256

This example duplicates the example A.3 in RFC 7516 for JSON Web Encryption (JWE).

Note: This example requires Chilkat v9.5.0.66 or greater.

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
string ls_AesWrappingKey
string ls_StrJwe
oleobject loo_Jwe2
string ls_OriginalPlaintext
oleobject loo_SbJwe

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

// Note: This example requires Chilkat v9.5.0.66 or greater.

ls_Plaintext = "Live long and prosper."

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":"A128KW","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","A128KW")
loo_JweProtHdr.AppendString("enc","A128CBC-HS256")
loo_Jwe.SetProtectedHeader(loo_JweProtHdr)

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

// The example A.3 in RFC 7516 uses the following 128-bit AES key,
// specified in JWK (JSON Web Key) format:
//      {"kty":"oct",
//       "k":"GawgguFyGrWKav7AX4VKUg"
//      }
// This is just a way of saying: The key type ("kty") is 
// a bunch of octets ("k") in base64url encoding.
// We can simply set the AES wrapping key like this:
ls_AesWrappingKey = "GawgguFyGrWKav7AX4VKUg"
loo_Jwe.SetWrappingKey(0,ls_AesWrappingKey,"base64url")

// 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
    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_Jwe2
    return
end if

// Set the AES wrap key.
loo_Jwe2.SetWrappingKey(0,ls_AesWrappingKey,"base64url")

// 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_Jwe2
    return
end if

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

// ---------------------------------------------------------------------------------
// It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.3.7
// because it was produced using the same AES Wrap key.

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

loo_SbJwe.Append("eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.")
loo_SbJwe.Append("6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ.")
loo_SbJwe.Append("AxY8DCtDaGlsbGljb3RoZQ.")
loo_SbJwe.Append("KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.")
loo_SbJwe.Append("U0m_YmjN04DJvceFICbCVQ")

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

loo_Jwe2.SetWrappingKey(0,ls_AesWrappingKey,"base64url")

// 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_Jwe2
    destroy loo_SbJwe
    return
end if

Write-Debug ls_OriginalPlaintext


destroy loo_Jwe
destroy loo_JweProtHdr
destroy loo_Jwe2
destroy loo_SbJwe