C++

Verify JWT with EdDSA / Ed25519 Signature

See more JSON Web Token (JWT) Examples

Note: This example requires Chilkat v9.5.0.84 or greater.

Demonstrates how to verify a JWT that was signed using an Ed25519 private key.

This example verifies the EdDSA signature. It also does the following:

• Checks to see if the time constraints ("nbf" and "exp") are valid.
• Recovers the original JOSE header.
• Recovers the original data.

C++

#include <CkPublicKey.h>
#include <CkJwt.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates how to verify a JWT with an EdDSA/Ed25519 Signature
    //  *** Requires Chilkat v9.5.0.84 or greater.

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

    //  Use this Ed25519 public key for verification

    const char *jsonPubKey = "{\"kty\": \"OKP\",\"alg\": \"EdDSA\",\"crv\": \"Ed25519\",\"x\": \"11qYAYKxCrfVS_7TyWQHOg7hcvPapiMlrwIaaPcHURo\"}";

    CkPublicKey pubKey;
    success = pubKey.LoadFromString(jsonPubKey);
    if (success == false) {
        std::cout << pubKey.lastErrorText() << "\r\n";
        return;
    }

    CkJwt jwt;
    const char *token = "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg";

    //  First verify the signature.
    bool sigVerified = jwt.VerifyJwtPk(token,pubKey);
    std::cout << "verified: " << sigVerified << "\r\n";

    if (sigVerified == false) {
        std::cout << jwt.lastErrorText() << "\r\n";
        return;
    }

    //  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.
    int leeway = 60;
    bool bTimeValid = jwt.IsTimeValid(token,leeway);
    std::cout << "time constraints valid: " << bTimeValid << "\r\n";

    //  Recover the original data (the payload).
    const char *payload = jwt.getPayload(token);
    std::cout << payload << "\r\n";

    //  Recover the original JOSE header in the same way:
    const char *joseHeader = jwt.getHeader(token);
    std::cout << joseHeader << "\r\n";
    }