(Visual Basic 6.0) Load ECC Public Key from JWK Format (JSON Web Key)

Demonstrates how to load an ECC public key from JWK (JSON Web Key) format.

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

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

' Note: This example requires Chilkat v9.5.0.66 or later.
Dim success As Long

' First build a JWK sample to load..
Dim json As New ChilkatJsonObject
success = json.UpdateString("kty","EC")
success = json.UpdateString("crv","P-256")
success = json.UpdateString("x","oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE")
success = json.UpdateString("y","vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU")

' The JSON contains the following:
' { 
'   "kty": "EC",
'   "crv": "P-256",
'   "x": "oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE",
'   "y": "vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU",
' }

' Note: The JSON can contain other members, such as "use", "kid", or anything else.  These will be ignored.
json.EmitCompact = 0

' Show the JWK string to be loaded:
Dim jwkStr As String
jwkStr = json.Emit()

Dim pubKey As New PublicKey
' The LoadFromString method will automatically detect the format.
success = pubKey.LoadFromString(jwkStr)
If (success <> 1) Then
    Debug.Print pubKey.LastErrorText
    Exit Sub
End If

' OK.. the JWK is loaded.  It can be used in whatever way desired...

' The key can be retrieved in any other format, such as XML or PEM..
Debug.Print pubKey.GetXml()

' XML output:
' <ECCPublicKey curve="secp256r1" 
'    x="A01532A3C0900053DE60FBEFEFCCA58793301598D308B41E6F4E364E388C2711" 
'    y="BEF432C599148C94143D4FF46C2CB73E3E6A41D7EEF23C047EA11E60667DE425">
'    MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAAAAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA///////////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSdNgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA//////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABKAVMqPAkABT3mD77+/MpYeTMBWY0wi0Hm9ONk44jCcRvvQyxZkUjJQUPU/0bCy3Pj5qQdfu8jwEfqEeYGZ95CU=
' </ECCPublicKey>

' Choose PCKS1 or PCKS8 PEM format..
Dim bPreferPkcs1 As Long
bPreferPkcs1 = 0
Debug.Print pubKey.GetPem(bPreferPkcs1)

' PEM output
' -----BEGIN PUBLIC KEY-----
' MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
' AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
' ///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
' NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
' RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
' //////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABKAVMqPAkABT3mD77+/MpYeT
' MBWY0wi0Hm9ONk44jCcRvvQyxZkUjJQUPU/0bCy3Pj5qQdfu8jwEfqEeYGZ95CU=
' -----END PUBLIC KEY-----