Swift Requires Chilkat v11.0.0+

Verify a JWT Created by the Amazon Cognito Service

See more JSON Web Token (JWT) Examples

Demonstrates how to verify a JWT created by the Amazon Cognito Service. Swift

func chilkatTest() {
    var success: Bool = false

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

    //  The public keys for this example are at https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json
    //  Let's get them:

    let http = CkoHttp()!
    let sbJsonKeys = CkoStringBuilder()!
    success = http.quickGetSb(url: "https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json", sbContent: sbJsonKeys)
    if success == false {
        print("\(http.lastErrorText!)")
        return
    }

    let jsonKeys = CkoJsonObject()!
    jsonKeys.loadSb(sb: sbJsonKeys)
    jsonKeys.emitCompact = false
    print("\(jsonKeys.emit()!)")

    //  Here are the keys:

    //  {
    //    "keys": [
    //      {
    //        "alg": "RS256",
    //        "e": "AQAB",
    //        "kid": "1A/L5Fsb2EsEwxy5E0cmCMS1BnMe6Jl6NXiMig4iNwU=",
    //        "kty": "RSA",
    //        "n": "y0w7BJrIJYi ... jKG27z2P3OKw",
    //        "use": "sig"
    //      },
    //      {
    //        "alg": "RS256",
    //        "e": "AQAB",
    //        "kid": "mos6VTJnvDwurY3ghJg6IAPUq+dMwl6CL/iThzJOkzg=",
    //        "kty": "RSA",
    //        "n": "qbIEH-7tg6yrT ... 3Fj94ooTd0w",
    //        "use": "sig"
    //      }
    //    ]
    //  }

    //  Try the 1st key.
    let jsonKey1 = CkoJsonObject()!
    jsonKeys.objectOf2(jsonPath: "keys[0]", jsonObj: jsonKey1)

    let pubKey1 = CkoPublicKey()!
    success = pubKey1.load(fromString: jsonKey1.emit())
    if success == false {
        print("\(pubKey1.lastErrorText!)")
        return
    }

    print("Success")

    let jwt = CkoJwt()!

    //  I did not include the an actual AWS Cognito token here because our test sample used customer-provided data..
    var token: String? = "eyJ..asXg"

    //  First verify the signature.
    var sigVerified: Bool = jwt.verifyPk(token: token, key: pubKey1)
    print("verified: \(sigVerified)")

    //  Let's see if the time constraints, if any, are valid.
    //  The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
    //  If the current system time is before the "nbf" time, or after the "exp" time,
    //  then IsTimeValid will return false/0.
    //  Also, we'll allow a leeway of 60 seconds to account for any clock skew.
    //  Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
    var leeway: Int = 60
    var bTimeValid: Bool = jwt.isTimeValid(jwt: token, leeway: leeway)
    print("time constraints valid: \(bTimeValid)")

    //  Now let's recover the original claims JSON (the payload).
    var payload: String? = jwt.getPayload(token: token)
    //  The payload will likely be in compact form:
    print("\(payload!)")

    //  We can format for human viewing by loading it into Chilkat's JSON object
    //  and emit.
    let json = CkoJsonObject()!
    success = json.load(json: payload)
    json.emitCompact = false
    print("\(json.emit()!)")

    //  We can recover the original JOSE header in the same way:
    var joseHeader: String? = jwt.getHeader(token: token)
    //  The payload will likely be in compact form:
    print("\(joseHeader!)")

    //  We can format for human viewing by loading it into Chilkat's JSON object
    //  and emit.
    success = json.load(json: joseHeader)
    json.emitCompact = false
    print("\(json.emit()!)")

}