(Lianja) Verify JWT with EdDSA / Ed25519 Signature

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.

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// 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

lcJsonPubKey = '{"kty": "OKP","alg": "EdDSA","crv": "Ed25519","x": "11qYAYKxCrfVS_7TyWQHOg7hcvPapiMlrwIaaPcHURo"}'

loPubKey = createobject("CkPublicKey")
llSuccess = loPubKey.LoadFromString(lcJsonPubKey)
if (llSuccess = .F.) then
    ? loPubKey.LastErrorText
    release loPubKey
    return
endif

loJwt = createobject("CkJwt")
lcToken = "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg"

// First verify the signature.
llSigVerified = loJwt.VerifyJwtPk(lcToken,loPubKey)
? "verified: " + str(llSigVerified)

if (llSigVerified = .F.) then
    ? loJwt.LastErrorText
    release loPubKey
    release loJwt
    return
endif

// 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.
lnLeeway = 60
llBTimeValid = loJwt.IsTimeValid(lcToken,lnLeeway)
? "time constraints valid: " + str(llBTimeValid)

// Recover the original data (the payload).
lcPayload = loJwt.GetPayload(lcToken)
? lcPayload

// Recover the original JOSE header in the same way:
lcJoseHeader = loJwt.GetHeader(lcToken)
? lcJoseHeader


release loPubKey
release loJwt