Passport: Cannot install laravel/passport 6.0.6 on laravel 5.6, php 7.1

[anhducbkhn]

My environment:
PHP: 7.1.17
This is composer.json file:
"require": { "php": "^7.1.3", "fideloper/proxy": "^4.0", "laravel/framework": "5.6.*", "laravel/tinker": "^1.0" }, "require-dev": { "filp/whoops": "^2.0", "fzaninotto/faker": "^1.4", "mockery/mockery": "^1.0", "nunomaduro/collision": "^2.0", "phpunit/phpunit": "^7.0" },
when i run command composer require laravel/passport got error:

````
Problem 1
- Conclusion: don't install laravel/passport v6.0.6
- Conclusion: don't install laravel/passport v6.0.5
- Conclusion: don't install laravel/passport v6.0.4
- Conclusion: don't install laravel/passport v6.0.3
- Conclusion: don't install laravel/passport v6.0.2
- Conclusion: don't install laravel/passport v6.0.1
- Conclusion: don't install laravel/passport v6.0.0
- Conclusion: don't install laravel/passport 6.0.x-dev
- Conclusion: remove paragonie/random_compat v9.99.99
- Installation request for laravel/passport ^6.0 -> satisfiable by laravel/passport[6.0.x-dev, v6.0.0, v6.0.1, v6.0.2, v6.0.3, v6.0.4, v6.0.5, v6.0.6].
- Conclusion: don't install paragonie/random_compat v9.99.99
- laravel/passport 6.0.x-dev requires league/oauth2-server ^7.0 -> satisfiable by league/oauth2-server[7.0.0, 7.1.0, 7.1.1, 7.2.0].
- league/oauth2-server 7.1.0 requires defuse/php-encryption ^2.1 -> satisfiable by defuse/php-encryption[v2.1.0, v2.2.0].
- league/oauth2-server 7.1.1 requires defuse/php-encryption ^2.1 -> satisfiable by defuse/php-encryption[v2.1.0, v2.2.0].
- league/oauth2-server 7.2.0 requires defuse/php-encryption ^2.1 -> satisfiable by defuse/php-encryption[v2.1.0, v2.2.0].
- league/oauth2-server 7.0.0 requires paragonie/random_compat ^2.0 -> satisfiable by paragonie/random_compat[v2.0.0, v2.0.1, v2.0.10, v2.0.11, v2.0.12, v2.0.13, v2.0.14, v2.0.15, v2.0.16, v2.0.17, v2.0.2, v2.0.3, v2.0.4, v2.0.5, v2.0.6, v2.0.7, v2.0.8, v2.0.9].
- defuse/php-encryption v2.1.0 requires paragonie/random_compat ~2.0 -> satisfiable by paragonie/random_compat[v2.0.0, v2.0.1, v2.0.10, v2.0.11, v2.0.12, v2.0.13, v2.0.14, v2.0.15, v2.0.16, v2.0.17, v2.0.2, v2.0.3, v2.0.4, v2.0.5, v2.0.6, v2.0.7, v2.0.8, v2.0.9].
- defuse/php-encryption v2.2.0 requires paragonie/random_compat ~2.0 -> satisfiable by paragonie/random_compat[v2.0.0, v2.0.1, v2.0.10, v2.0.11, v2.0.12, v2.0.13, v2.0.14, v2.0.15, v2.0.16, v2.0.17, v2.0.2, v2.0.3, v2.0.4, v2.0.5, v2.0.6, v2.0.7, v2.0.8, v2.0.9].
- Can only install one of: paragonie/random_compat[v2.0.0, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.1, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.10, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.11, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.12, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.13, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.14, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.15, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.16, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.17, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.2, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.3, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.4, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.5, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.6, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.7, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.8, v9.99.99].
- Can only install one of: paragonie/random_compat[v2.0.9, v9.99.99].
- Installation request for paragonie/random_compat (locked at v9.99.99) -> satisfiable by paragonie/random_compat[v9.99.99].

````
What should I do?

[peppermintology]

@anhducbkhn I've experienced the same issue on a fresh install of Laravel 5.6 and PHP 7.2. I managed to get Passport installed by manually adding "laravel/passport": "^6.0", to my composer.json file and running composer update.

[anhducbkhn]

@peppermintology it worked thanks