How to generate a short token with laravel passport?

Question

I am using laravel passport with password grant mode , i found it generated access token is very long , like this :

{
    "token_type": "Bearer",
    "expires_in": 31536000,
    "access_token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6IjRmOTlkNDI2ZmIxN2I5OGVmNzExYzMyOGQ2YzMwODBhOGY4OGVjYWI4Yjg3Zjg2MmFkNWFlNGI5MzdiYjg0MGQ3MDk2NWI2OWY4NDk3MTE0In0.eyJhdWQiOiIyIiwianRpIjoiNGY5OWQ0MjZmYjE3Yjk4ZWY3MTFjMzI4ZDZjMzA4MGE4Zjg4ZWNhYjhiODdmODYyYWQ1YWU0YjkzN2JiODQwZDcwOTY1YjY5Zjg0OTcxMTQiLCJpYXQiOjE0ODk0NDAzODEsIm5iZiI6MTQ4OTQ0MDM4MSwiZXhwIjoxNTIwOTc2MzgxLCJzdWIiOiIyIiwic2NvcGVzIjpbXX0.XEY0vMoUt6Z9cWMkELQhfcaC2uab8odQLmIVTh8YWULSYOPuw4vpTDFurgU2vflM8-5PYuIIOnw8-8CQVZvetkYLpp2r0GqdNPIcCwlZNh9zRFLLigJ1vm4GKsbGozoDieR9FBpvQ2K9gFM0V4kwjSwx74fdlC1imC1rZ8qRYy5e1zctrMSrVcGcT5F4PTm4DdTN50IRcsOIJK9T6Wgec-iYmey0-xKg0UQroCF6rZUtC0VlH8XwhW_1QfrCl7dkKIcEbWi4pgzDpwrLMZgLAQpPktCP2G9SujC99e7M_L3C8Y647enwUQSTKtp6xNyTyyHSqS0NAxU4U0TFTICMPH5D_L_WaTeBCLS3MdwM3cmTQdkjdXjljjurHld3yEvVemo7oAr2Wb_HOC1uFET0ndeVGI1ZhgM-AuUBy1dJrV4a0iyUIiVtO12LadFIK2m9h0YQlawN1me_HQy6FxdBQuMJ3WIuR3Mwp79RHkoYKFQGvfxTTK8N0emZzmLl5rODp6n7I1UKDb_g7weHdmFP2paTJCApikIXidYA-QXa1i2qMfCwB7gF_kqBvrOyL29wFFRBc_ACRA-0I8iEhZ18vF7htKkPgWoYyPzBKHjVJ4vrxV_VxbGcszIC5byAJKcmpcXEOnFXkFV7NF-tOb___hw9THTjYQmznM1OS__U8zA",
    "refresh_token": "RXFyjx21XaLKgkOXa5zZyVbhRqXDsRZbfsFZmxst4Un0+VWtl0xTn/jIOPzApdqFFoTBCH08Ytjxf6SlcEOIUuHhN5+V7wuun/nFCuKIoC2T1xg9Ny2KkzRq0IF+bSBgtZ5QXfu+ILkCSZ/uh39rRxpoO4aqcnJp2Bvj5wuVcFra2nnPCu/Rfs+AN7MA5H8WgzfLmsIFsh3/rtzU4KboFR0rQE4MrDecrJCmCjvAJS52LLdFhDnNi/KdjhxBXY7jpgXZF+HOLAribGPn9COoC7B9zGoYHA3zaOMopsJ+NaRTHsuf2VbXlrQ4eXME5XVB4+TpgU8LGipK1jv5Ndhfu/VJaxgRk94VEuAcYu4vWUEdNl5Y4sRPDSlIpwjnXxdiiAUuNnvbrUaRD/qStJmmzQiWe7M07qVTHp4PNrVOVhjZkIsFMWoMsRHWtDu0eRbde3tBOhIWUCwxndp9Ma9DlSwuq6jmhv/mi62QboYjgZrWJAqLSIeP13mRyH0kNR4LCauCpiXgaPPTywBBfYpEIn34DQeo9QQfvnnut9ky8hRgniQjhGbvgeyIOS7WgmDR0Wmbt0jwLY5MWl5WuyhAJztQPnt0sTLxWzey0ZCRC5DWMSzt/g8cTL7cfjCxPYYdLCsAYE6eXTEaA3zZLre2GnBJwwE0+3bIRctQDH9zYRE="
}

I know a long token will be safer, but over one thousand characters seems a bit scary. In my impression, JWT is commonly very small, but here, this generated token is so long, so big .

I want to generate a shorter token , what is good way to do it?

If laravel passport is able to specify lenght of token?

Answer 1

If you feel need to shorten the token length, maybe you should regenerate the key pair files with this command:

php artisan  passport:keys  --length=512 --force

Answer 2

The length of the JWT depends on 2 things: your payload size and the encryption algorithm used. Laravel appears to be using public/private key hashing (RS256) for their JWTs, which requires longer key lengths than say using HS256 algorithm. You can see it if you go to https://jwt.io/ and paste in your token.

If you want to use Laravel Passport then there is no easy way around this length requirement. You can either create libs with methods that override the Passport method used to set the hashing algorithm (not recommended that you go down this rabbit hole), or you can just not use Passport and instead implement your own JWT token authentication system, or you can just live with the long tokens.

Answer 3

Using Passport version less than "^7.0.0" the JTI (id of token saved in oauth_access_tokens table) is in the header as well as in the body of the JWT. Upgrading to version "^8.0.0" can reduce the JWT token with another 100 bytes or so because they removed the JTI from the header.

So combining the upgrade to version 8 and the answer by Sreng-s, my JWT is down to 340 bytes. It's better than the 1070 bytes I started out with but it's still really big considering it's being sent with every request.

Any further improvements would be very much appreciated.