Visual Basic 6.0 Requires Chilkat v11.0.0+

Validate JWS Using RSASSA-PKCS1-v1_5 SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) that uses RSASSA-PKCS1-v1_5 SHA-256. Visual Basic 6.0

Dim success As Long
success = 0

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

'  This example takes a JSON signature in compact serialization format,
'  and uses an RSA public key to validate and recover the protected header and payload.

'  We only need a public key for signature validation.  This is the RSA public key
'  that is used:

'       {"kty":"RSA", 
'        "n":"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx
'             HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs
'             D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH
'             SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV
'             MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8
'             NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ", 
'        "e":"AQAB"
'       }

Dim sbPubKey As New ChilkatStringBuilder
success = sbPubKey.Append("{""kty"":""RSA"",")
success = sbPubKey.Append("""n"":""ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx")
success = sbPubKey.Append("HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs")
success = sbPubKey.Append("D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH")
success = sbPubKey.Append("SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV")
success = sbPubKey.Append("MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8")
success = sbPubKey.Append("NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ"",")
success = sbPubKey.Append("""e"":""AQAB""")
success = sbPubKey.Append("}")

Dim pubKey As New PublicKey
success = pubKey.LoadFromString(sbPubKey.GetAsString())
If (success = 0) Then
    Debug.Print pubKey.LastErrorText
    Exit Sub
End If

Dim jws As New ChilkatJws

'  Set the RSA public key:
Dim signatureIndex As Long
signatureIndex = 0
success = jws.SetPublicKey(signatureIndex,pubKey)

'  Load the JWS.
Dim sbJws As New ChilkatStringBuilder
success = sbJws.Append("eyJhbGciOiJSUzI1NiJ9")
success = sbJws.Append(".")
success = sbJws.Append("eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt")
success = sbJws.Append("cGxlLmNvbS9pc19yb290Ijp0cnVlfQ")
success = sbJws.Append(".")
success = sbJws.Append("cC4hiUPoj9Eetdgtv3hF80EGrhuB__dzERat0XF9g2VtQgr9PJbu3XOiZj5RZmh7")
success = sbJws.Append("AAuHIm4Bh-0Qc_lF5YKt_O8W2Fp5jujGbds9uJdbF9CUAr7t1dnZcAcQjbKBYNX4")
success = sbJws.Append("BAynRFdiuB--f_nZLgrnbyTyWzO75vRK5h6xBArLIARNPvkSjtQBMHlb1L07Qe7K")
success = sbJws.Append("0GarZRmB_eSN9383LcOLn6_dO--xi12jzDwusC-eOkHWEsqtFZESc6BfI7noOPqv")
success = sbJws.Append("hJ1phCnvWh6IeYI2w9QOYEUipUTI8np6LbgGY9Fs98rqVt5AXLIhWkWywlVmtVrB")
success = sbJws.Append("p0igcN_IoypGlUPQGe77Rw")

success = jws.LoadJwsSb(sbJws)
If (success = 0) Then
    Debug.Print jws.LastErrorText
    Exit Sub
End If

'  Validate the 1st (and only) signature at index 0..
Dim v As Long
v = jws.Validate(signatureIndex)
If (v < 0) Then
    '  Perhaps Chilkat was not unlocked or the trial expired..
    Debug.Print "Method call failed for some other reason."
    Debug.Print jws.LastErrorText
    Exit Sub
End If

If (v = 0) Then
    Debug.Print "Invalid signature.  The RSA key was incorrect, the JWS was invalid, or both."
    Exit Sub
End If

'  If we get here, the signature was validated..
Debug.Print "Signature validated."
Debug.Print "--"

'  Recover the original content:
Debug.Print "Recovered content:"
Debug.Print jws.GetPayload("utf-8")
Debug.Print "--"

'  Examine the protected header:

Dim joseHeader As New ChilkatJsonObject
success = jws.GetProtectedH(signatureIndex,joseHeader)
If (success = 0) Then
    Debug.Print jws.LastErrorText
    Exit Sub
End If

joseHeader.EmitCompact = 0

Debug.Print "Protected (JOSE) header:"
Debug.Print joseHeader.Emit()

'  Output:

'  	Signature validated.
'  	--
'  	Recovered content:
'  	{"iss":"joe", 
'  	 "exp":1300819380,
'  	 "http://example.com/is_root":true}
'  	--
'  	Protected (JOSE) header:
'  	{ 
'  	  "alg": "RS256"
'  	}