SQL Server

JWE using A256GCMKW

See more JSON Web Encryption (JWE) Examples

This example demonstrates creating a JCE with AES GCM key wrap. 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.

    DECLARE @plaintext nvarchar(4000)
    SELECT @plaintext = 'My text to enrypt'

    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: 

    --         {
    --             "alg": "A256GCMKW",
    --             "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
    --             "tag": "kfPduVQ3T3H6vnewt--ksw",
    --             "iv": "KkYT0GX_2jHlfqN_",
    --             "enc": "A128CBC-HS256"
    --         }

    DECLARE @jweProtHdr int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @jweProtHdr OUT

    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'alg', 'A256GCMKW'
    -- kid is optional
    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'kid', '18ec08e1-bfa9-4d95-b205-2b4dd1d4321d'
    -- tag is optional
    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'tag', 'kfPduVQ3T3H6vnewt--ksw'
    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'enc', 'A256GCM'
    -- the iv should be 16 random chars.
    DECLARE @prng int
    EXEC @hr = sp_OACreate 'Chilkat.Prng', @prng OUT

    EXEC sp_OAMethod @prng, 'RandomString', @sTmp0 OUT, 16, 1, 1, 1
    EXEC sp_OAMethod @jweProtHdr, 'AppendString', @success OUT, 'iv', @sTmp0
    EXEC sp_OAMethod @jwe, 'SetProtectedHeader', @success OUT, @jweProtHdr


    EXEC sp_OAMethod @jweProtHdr, 'Emit', @sTmp0 OUT
    PRINT 'JWE Protected Header: ' + @sTmp0

    PRINT '--'

    -- Given that we have 256-bit AES, our key should be 32 bytes.
    -- The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
    -- ascii chars directly as the key.
    DECLARE @aesWrappingKey nvarchar(4000)
    SELECT @aesWrappingKey = '2baf4f730f5e4542b428593ef9cceb0e'
    EXEC sp_OAMethod @jwe, 'SetWrappingKey', @success OUT, 0, @aesWrappingKey, 'ascii'

    -- 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
        EXEC @hr = sp_OADestroy @prng
        RETURN
      END

    -- Show the JWE we just created:

    PRINT @strJwe

    -- Decrypt the JWE that was just produced.
    -- 1) Load the JWE.
    -- 2) Set the AES wrapping key.
    -- 3) Decrypt.
    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 @prng
        EXEC @hr = sp_OADestroy @jwe2
        RETURN
      END
    -- Set the AES wrap key.  Important to use "ascii"
    EXEC sp_OAMethod @jwe2, 'SetWrappingKey', @success OUT, 0, @aesWrappingKey, 'ascii'

    -- 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 @prng
        EXEC @hr = sp_OADestroy @jwe2
        RETURN
      END


    PRINT 'original text: '

    PRINT @originalPlaintext

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


END
GO