(PowerBuilder) Validate a Google ID Token

Demonstrates how to verify the signature of a Google id token.

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

integer li_rc
oleobject loo_Http
string ls_JwkStr
oleobject loo_Json
integer li_Success
oleobject loo_JsonToken
oleobject loo_SbIdToken
string ls_Sig_b64Url
string ls_HeaderPlusPayload
oleobject loo_Rsa
integer li_NumKeys
integer i
oleobject loo_JsonKey
oleobject loo_PubKey
integer li_BVerified

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

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

// First get the public key we'll be needing..
ls_JwkStr = loo_Http.QuickGetStr("https://www.googleapis.com/oauth2/v3/certs")
if loo_Http.LastMethodSuccess = 0 then
    Write-Debug loo_Http.LastErrorText
    destroy loo_Http
    return
end if

// We have the following:

//     {
//       "keys": [
// 	{
// 	  "kid": "e8732db06287515556213b80acbcfd08cfb302a9",
// 	  "n": "4RIrO30287Wsq3gqXCMkUYMVAeI3H8...w2mbMNEBQ",
// 	  "kty": "RSA",
// 	  "e": "AQAB",
// 	  "alg": "RS256",
// 	  "use": "sig"
// 	},
// 	{
// 	  "kid": "8462a71da4f6d611fc0fecf0fc4ba9c37d65e6cd",
// 	  "e": "AQAB",
// 	  "n": "xT_ngLZNmT5GBtJZeTB...Ft4gK0eoFi0d3l8bcw",
// 	  "alg": "RS256",
// 	  "use": "sig",
// 	  "kty": "RSA"
// 	}
//       ]
//     }

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

li_Success = loo_Json.Load(ls_JwkStr)

// -------------------------------------------------

// Load the following..

//  {
//   "access_token": "ya29.a0...0f",
//   "expires_in": 3599,
//   "scope": "openid https://www.googleapis.com/auth/userinfo.email",
//   "token_type": "Bearer",
//   "id_token": "eyJhb...o5nQ"
// }

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

li_Success = loo_JsonToken.LoadFile("qa_data/tokens/google_sample_id_token.json")
if li_Success = 0 then
    Write-Debug "Failed to load the JSON file..."
    destroy loo_Http
    destroy loo_Json
    destroy loo_JsonToken
    return
end if

// Get the id_token;
loo_SbIdToken = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbIdToken.ConnectToNewObject("Chilkat.StringBuilder")

li_Success = loo_SbIdToken.Append(loo_JsonToken.StringOf("id_token"))

// Get the signature in base64url format.
// The header + payload remains in sbIdToken.
ls_Sig_b64Url = loo_SbIdToken.GetAfterFinal(".",1)
ls_HeaderPlusPayload = loo_SbIdToken.GetAsString()

Write-Debug ls_Sig_b64Url
Write-Debug ls_HeaderPlusPayload

// ---------------------------------------------

// Try validating with each cert's public key.
// Hopefully one will be the key that verifies.

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

loo_Rsa.EncodingMode = "base64url"

li_NumKeys = loo_Json.SizeOfArray("keys")
i = 0
do while i < li_NumKeys
    loo_Json.I = i
    loo_JsonKey = loo_Json.ObjectOf("keys[i]")
    loo_PubKey = create oleobject
    // Use "Chilkat_9_5_0.PublicKey" for versions of Chilkat < 10.0.0
    li_rc = loo_PubKey.ConnectToNewObject("Chilkat.PublicKey")

    li_Success = loo_PubKey.LoadFromString(loo_JsonKey.Emit())
    if li_Success = 0 then
        Write-Debug loo_PubKey.LastErrorText
        destroy loo_Http
        destroy loo_Json
        destroy loo_JsonToken
        destroy loo_SbIdToken
        destroy loo_Rsa
        destroy loo_PubKey
        return
    end if

    Write-Debug string(i)
    Write-Debug loo_PubKey.GetPem(1)
    destroy loo_JsonKey

    li_Success = loo_Rsa.ImportPublicKeyObj(loo_PubKey)

    li_BVerified = loo_Rsa.VerifyStringENC(ls_HeaderPlusPayload,"sha256",ls_Sig_b64Url)
    Write-Debug "bVerified = " + string(li_BVerified)

    i = i + 1
loop

// The output is:

// 0
// -----BEGIN RSA PUBLIC KEY-----
// MIIBCgKCAQEA4RIrO30287Wsq3gqXCMkUYMVAeI3H8LVE6IXR1krdFeGnZLiGUPw
// cbkeVpXf3lmJdsStOg+jijces2DZCfPyIBiQuLYfxxmAZE6ErJ0QJFg1stwli2Pz
// 9ncYhFoqi8pXr7kEzEJBTzX4thuw56ydbGsshSEznPXoerCJOc7UI2+n0wFCWQ4Y
// LHbh/PrWt4vdadyUUUW/QpQHXQLdD8q/Qwqdj0O9zlJE7R6Elw2E9EqnHyIGu1hm
// LxhqrTru1M18SUhONYbVskV/BCEdVKs//X96849HorWQDCAgVMWfGsdMVq55FAdJ
// 680N5UmQDRynIZ4+PeNGN4S9iw2mbMNEBQIDAQAB
// -----END RSA PUBLIC KEY-----
// 
// bVerified = True
// 1
// -----BEGIN RSA PUBLIC KEY-----
// MIIBCgKCAQEAxT/ngLZNmT5GBdkLtJZjNeTB+8B5yWgrq/e5eMZ1hrZhcmLK+dSn
// IkpOPV8/OekV67EnQ7I4II2rcNJnHGrGKZziXO3XN2gtUHE+mBJC99oULSbX/QwB
// Kz7gC/IBPq9EuxTt6Oq6fPkVQ9DbRIgWJSEGBF/KRaNl3kyAlIZfpY7XgHyJTTv8
// E7yAcYKPR+36gzdl+ps0sDLKzUuAtZNq8llK0u80z6AtAUIYwWdkEhM9upy6keKI
// TasIxcsO7M6kZPINUSbh6t5VAm8FuqRmxpgg+9c9/GQSGd89InVypoVzWLQ+wOGg
// 5G4H6JqIgtj0TRFt4gK0eoFi2U0d3l8bcwIDAQAB
// -----END RSA PUBLIC KEY-----
// 
// bVerified = False


destroy loo_Http
destroy loo_Json
destroy loo_JsonToken
destroy loo_SbIdToken
destroy loo_Rsa
destroy loo_PubKey