Xbase++

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.

Xbase++

LOCAL nSuccess
LOCAL oPubKey
LOCAL oSb

nSuccess := 0

oPubKey := CreateObject("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 := CreateObject("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..
nSuccess := oPubKey:LoadFromString(oSb:GetAsString())
IF (nSuccess != 1)
    ? oPubKey:LastErrorText
    oPubKey:destroy()
    oSb:destroy()
    RETURN
ENDIF

//  Get the JWK thumbprint (using SHA256)
? "JWK thumbprint: " + oPubKey:GetJwkThumbprint("SHA256")

//  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("}")

nSuccess := oPubKey:LoadFromString(oSb:GetAsString())
IF (nSuccess != 1)
    ? oPubKey:LastErrorText
    oPubKey:destroy()
    oSb:destroy()
    RETURN
ENDIF

//  Get the JWK thumbprint (using SHA256)
? "JWK thumbprint: " + oPubKey:GetJwkThumbprint("SHA256")

//  Output:
//  JWK thumbprint: 8fm8079s3nu4FLV_7dVJoJ69A8XCXn7Za2mtaWCnxR4

oPubKey:destroy()
oSb:destroy()