(SQL Server) Validate JWS Using HMAC SHA-256

Validates a JSON Web Signature (JWS) using HMAC SHA-256.

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

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

    -- This example takes a JSON signature in compact serialization format,
    -- and uses a MAC key to validate and recover the protected header and payload.

    DECLARE @jws int
    -- Use "Chilkat_9_5_0.Jws" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Jws', @jws OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Set the HMAC key:
    DECLARE @hmacKey nvarchar(4000)
    SELECT @hmacKey = 'AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow'
    DECLARE @signatureIndex int
    SELECT @signatureIndex = 0
    DECLARE @success int
    EXEC sp_OAMethod @jws, 'SetMacKey', @success OUT, @signatureIndex, @hmacKey, 'base64url'

    -- Load the JWS.
    DECLARE @jwsCompact nvarchar(4000)
    SELECT @jwsCompact = 'eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk'
    DECLARE @success int
    EXEC sp_OAMethod @jws, 'LoadJws', @success OUT, @jwsCompact

    -- Validate the 1st (and only) signature at index 0..
    DECLARE @v int
    EXEC sp_OAMethod @jws, 'Validate', @v OUT, @signatureIndex
    IF @v < 0
      BEGIN
        -- Perhaps Chilkat was not unlocked or the trial expired..

        PRINT 'Method call failed for some other reason.'
        EXEC sp_OAGetProperty @jws, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @jws
        RETURN
      END
    IF @v = 0
      BEGIN

        PRINT 'Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.'
        EXEC @hr = sp_OADestroy @jws
        RETURN
      END

    -- If we get here, the signature was validated..

    PRINT 'Signature validated.'

    -- Recover the original content:

    PRINT 'Recovered content:'
    EXEC sp_OAMethod @jws, 'GetPayload', @sTmp0 OUT, 'utf-8'
    PRINT @sTmp0

    -- Examine the protected header:
    DECLARE @joseHeader int
    EXEC sp_OAMethod @jws, 'GetProtectedHeader', @joseHeader OUT, @signatureIndex
    EXEC sp_OAGetProperty @jws, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN

        PRINT 'No protected header found at the given index.'
        EXEC @hr = sp_OADestroy @jws
        RETURN
      END
    EXEC sp_OASetProperty @joseHeader, 'EmitCompact', 0


    PRINT 'Protected (JOSE) header:'
    EXEC sp_OAMethod @joseHeader, 'Emit', @sTmp0 OUT
    PRINT @sTmp0
    EXEC @hr = sp_OADestroy @joseHeader

    -- Output:

    -- 	Signature validated.
    -- 	Recovered content:
    -- 	{"iss":"joe",
    -- 	 "exp":1300819380,
    -- 	 "http://example.com/is_root":true}
    -- 	Protected (JOSE) header:
    -- 	{ 
    -- 	  "typ": "JWT",
    -- 	  "alg": "HS256"
    -- 	}

    EXEC @hr = sp_OADestroy @jws


END
GO