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Compute JWK Thumbprint for RSA and EC Public Keys

See more ECC Examples

Demonstrates how to compute a JSON Web Key thumbprint for a public key (RSA or ECC).

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

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Local $bSuccess = False

$oPubKey = ObjCreate("Chilkat.PublicKey")

; A public key can be loaded from any format (binary DER, PEM, etc.)
; This example will load the public keys from JWK format, 
; and will then compute the JWK thumbprint.

; First do it for an RSA public key...

$oSb = ObjCreate("Chilkat.StringBuilder")
$oSb.Append("{")
$oSb.Append("""kty"": ""RSA"",")
$oSb.Append("""n"": ""0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAt")
$oSb.Append("VT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMstn6")
$oSb.Append("4tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FD")
$oSb.Append("W2QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n9")
$oSb.Append("1CbOpbISD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINH")
$oSb.Append("aQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw"",")
$oSb.Append("""e"": ""AQAB"",")
$oSb.Append("""alg"": ""RS256"",")
$oSb.Append("""kid"": ""2011-04-29""")
$oSb.Append("}")

; The JWK format is automatically detected..
$bSuccess = $oPubKey.LoadFromString($oSb.GetAsString())
If ($bSuccess <> True) Then
    ConsoleWrite($oPubKey.LastErrorText & @CRLF)
    Exit
EndIf

; Get the JWK thumbprint (using SHA256)
ConsoleWrite("JWK thumbprint: " & $oPubKey.GetJwkThumbprint("SHA256") & @CRLF)

; Output:
; JWK thumbprint: NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs

; --------------------------------------------------------------
; Now let's do an EC public key:
$oSb.Clear 
$oSb.Append("{ ")
$oSb.Append("  ""kty"": ""EC"",")
$oSb.Append("  ""crv"": ""P-256"",")
$oSb.Append("  ""x"": ""tDeeYABgKEAbWicYPCEEI8sP4SRIhHKcHDW7VqrB4LA"",")
$oSb.Append("  ""y"": ""J08HOoIZ0rX2Me3bNFZUltfxIk1Hrc8FsLu8VaSxsMI""")
$oSb.Append("}")

$bSuccess = $oPubKey.LoadFromString($oSb.GetAsString())
If ($bSuccess <> True) Then
    ConsoleWrite($oPubKey.LastErrorText & @CRLF)
    Exit
EndIf

; Get the JWK thumbprint (using SHA256)
ConsoleWrite("JWK thumbprint: " & $oPubKey.GetJwkThumbprint("SHA256") & @CRLF)

; Output:
; JWK thumbprint: 8fm8079s3nu4FLV_7dVJoJ69A8XCXn7Za2mtaWCnxR4