SQL Server

JWE using "dir" Direct use of Shared Symmetric Key

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

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

SQL Server

-- 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)
    DECLARE @success int
    SELECT @success = 0

    -- 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.

    DECLARE @plaintext nvarchar(4000)
    SELECT @plaintext = 'Live long and prosper.'

    DECLARE @jwe int
    EXEC @hr = sp_OACreate 'Chilkat.Jwe', @jwe OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- First build the JWE Protected Header..
    DECLARE @jweProtHdr int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @jweProtHdr OUT

    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'alg', 'dir'
    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'enc', 'A128GCM'

    -- Don't forget to actually provide the protected header to the JWE object:
    EXEC sp_OAMethod @jwe, 'SetProtectedHeader', @success OUT, @jweProtHdr

    -- The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
    -- Given that the "alg" = "dir", we are to directly specify the AES GCM key.
    -- (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

    -- Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

    -- The SetWrappingKey method is also used for "dir" direct keys.
    -- However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
    -- which is specified by calling SetWrappingKey with an index of 0.

    DECLARE @recipientIndex int
    SELECT @recipientIndex = 0
    EXEC sp_OAMethod @jwe, 'SetWrappingKey', @success OUT, @recipientIndex, '000102030405060708090A0B0C0D0E0F', 'hex'

    -- Encrypt and return the JWE:
    DECLARE @strJwe nvarchar(4000)
    EXEC sp_OAMethod @jwe, 'Encrypt', @strJwe OUT, @plaintext, 'utf-8'
    EXEC sp_OAGetProperty @jwe, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @jwe, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @jwe
        EXEC @hr = sp_OADestroy @jweProtHdr
        RETURN
      END

    -- Show the JWE we just created:

    PRINT @strJwe

    -- Decrypt the JWE.
    DECLARE @jwe2 int
    EXEC @hr = sp_OACreate 'Chilkat.Jwe', @jwe2 OUT

    EXEC sp_OAMethod @jwe2, 'LoadJwe', @success OUT, @strJwe
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @jwe2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @jwe
        EXEC @hr = sp_OADestroy @jweProtHdr
        EXEC @hr = sp_OADestroy @jwe2
        RETURN
      END
    EXEC sp_OAMethod @jwe2, 'SetWrappingKey', @success OUT, 0, '000102030405060708090A0B0C0D0E0F', 'hex'

    -- Decrypt.
    DECLARE @originalPlaintext nvarchar(4000)
    EXEC sp_OAMethod @jwe2, 'Decrypt', @originalPlaintext OUT, 0, 'utf-8'
    EXEC sp_OAGetProperty @jwe2, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @jwe2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @jwe
        EXEC @hr = sp_OADestroy @jweProtHdr
        EXEC @hr = sp_OADestroy @jwe2
        RETURN
      END


    PRINT 'original text: '

    PRINT @originalPlaintext

    -- Sample output:
    -- eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
    -- original text: 
    -- Live long and prosper.

    EXEC @hr = sp_OADestroy @jwe
    EXEC @hr = sp_OADestroy @jweProtHdr
    EXEC @hr = sp_OADestroy @jwe2


END
GO