rfc:improve_hash_hkdf_pramater
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rfc:improve_hash_hkdf_pramater [2017/02/05 03:48] – yohgaki | rfc:improve_hash_hkdf_pramater [2017/02/05 06:30] – yohgaki | ||
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=== Per user data encryption === | === Per user data encryption === | ||
- | - Get the secret password hash generated by hash_password() for the user (ikm) | + | - Get the secret password hash generated by hash_password() for the user. $ikm |
- | - Get application secret salt stored in secure place. e.g. $_ENV (salt) | + | - Get application secret salt stored in secure place. e.g. $_ENV $salt |
- | - Generate HKDF hash value with 1 and 2 (hash_hkdf(' | + | - Generate HKDF hash value with 1 and 2. < |
- Encrypt the user data with the key from 3 | - Encrypt the user data with the key from 3 | ||
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See also **Security Note** section blow. The same technique can be used for per user encryption key. | See also **Security Note** section blow. The same technique can be used for per user encryption key. | ||
- | Other way to encrypt per user: | + | Other way to encrypt per user |
- | - Get system shared secret encryption | + | - Get system shared secret encryption key from secure place. |
- | - Get user ID which is unique in the system | + | - Get user ID which is unique in the system. $info |
- | - Generate HKDF hash value 1 and 2. (hash_hkdf(' | + | - Generate HKDF hash value 1 and 2. < |
- | Note that both method uses " | + | |
+ | Note that both method uses " | ||
There are many usages other than these two. Users can choose appropriate method for their needs. | There are many usages other than these two. Users can choose appropriate method for their needs. | ||
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Setting up CSRF token | Setting up CSRF token | ||
- | - Get expiration timestamp | + | - Get expiration timestamp. ($salt) |
- | - Generate HKDF value with 1 and session ID | + | - Generate HKDF value with 1 and session ID ($ikm). |
- | - Send key from 2 and timestamp from 1 to browser as CSRF token | + | - Send key from 2 and timestamp from 1 to browser as CSRF token. |
Verifying CSRF token | Verifying CSRF token | ||
- | - Get HKDF key and timestamp(salt) value from request | + | - Get HKDF key and timestamp($salt) value from request. |
- | - Check if timestamp is not expired | + | - Check if timestamp is not expired. |
- | - Generate HKDF value session ID and timestamp(salt) | + | - Generate HKDF value from session ID($ikm) |
- | - Compare HKDF value sent by browser and server generated HKDF value if it matches | + | - Compare HKDF value sent by browser and server generated HKDF value if it matches. |
Secure CSRF token expiration can be defined with this method regardless of session ID lifetime. i.e. You can set short CSRF token expiration securely. | Secure CSRF token expiration can be defined with this method regardless of session ID lifetime. i.e. You can set short CSRF token expiration securely. | ||
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https:// | https:// | ||
- | Therefore, use of session ID as CSRF token key source is not recommended. You are better to use separate key for CSRF token generation in $_SESSION. e.g. $_SESSION[' | + | Therefore, use of session ID as CSRF token key source is not recommended. You are better to use separate key for CSRF token generation in $_SESSION. e.g. $_SESSION[' |
==Use of info parameter== | ==Use of info parameter== | ||
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===== Proposal ===== | ===== Proposal ===== | ||
- | Internet RFC clearly recommends " | + | Internet RFC clearly recommends " |
- | Change hash_hkdf() from | + | Change hash_hkdf() |
< | < | ||
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From user perspective, | From user perspective, | ||
- | Unlike " | + | Unlike " |
- | Typical PHP applications that need HKDF can use (or should use) salt for security reasons as examples above. Users should consider if salt can be used or not. If use of salt is impossible, then it should set to be empty. | + | Typical PHP applications that need HKDF can use (or should use) salt for security reasons as examples above. Users should consider if salt can be used or not. If use of salt is impossible, then it should set to be empty. |
===== Discussions ===== | ===== Discussions ===== |
rfc/improve_hash_hkdf_pramater.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1