Name : perl-Session-Storage-Secure
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Version : 1.0.0
| Vendor : obs://build_opensuse_org/devel:languages:perl
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Release : 1.1
| Date : 2021-03-24 04:11:30
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Group : Unspecified
| Source RPM : perl-Session-Storage-Secure-1.0.0-1.1.src.rpm
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Size : 0.06 MB
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Packager : (none)
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Summary : Encrypted, expiring, compressed, serialized session data with integrity
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Description :
This module implements a secure way to encode session data. It is primarily intended for storing session data in browser cookies, but could be used with other backend storage where security of stored session data is important.
Features include:
* Data serialization and compression using Sereal
* Data encryption using AES with a unique derived key per encoded session
* Enforced expiration timestamp (optional)
* Integrity protected with a message authentication code (MAC)
The storage protocol used in this module is based heavily on at http://www.cse.msu.edu/~alexliu/publications/Cookie/Cookie_COMNET.pdf by Alex Liu and others. Liu proposes a session cookie value as follows:
user|expiration|E(data,k)|HMAC(user|expiration|data|ssl-key,k)
where
| denotes concatenation with a separator character E(p,q) is a symmetric encryption of p with key q HMAC(p,q) is a keyed message hash of p with key q k is HMAC(user|expiration, sk) sk is a secret key shared by all servers ssl-key is an SSL session key
Because SSL session keys are not readily available (and SSL termination may happen prior to the application server), we omit \'ssl-key\'. This weakens protection against replay attacks if an attacker can break the SSL session key and intercept messages.
Using \'user\' and \'expiration\' to generate the encryption and MAC keys was a method proposed to ensure unique keys to defeat volume attacks against the secret key. Rather than rely on those for uniqueness (with the unfortunate side effect of revealing user names and prohibiting anonymous sessions), we replace \'user\' with a cryptographically-strong random salt value.
The original proposal also calculates a MAC based on unencrypted data. We instead calculate the MAC based on the encrypted data. This avoids an extra step decrypting invalid messages. Because the salt is already encoded into the key, we omit it from the MAC input.
Therefore, the session storage protocol used by this module is as follows:
salt|expiration|E(data,k)|HMAC(expiration|E(data,k),k)
where
| denotes concatenation with a separator character E(p,q) is a symmetric encryption of p with key q HMAC(p,q) is a keyed message hash of p with key q k is HMAC(salt, sk) sk is a secret key shared by all servers
The salt value is generated using Math::Random::ISAAC::XS, seeded from Crypt::URandom.
The HMAC algorithm is \'hmac_sha256\' from Digest::SHA. Encryption is done by Crypt::CBC using Crypt::Rijndael (AES). The ciphertext and MAC\'s in the cookie are Base64 encoded by MIME::Base64 by default.
During session retrieval, if the MAC does not authenticate or if the expiration is set and in the past, the session will be discarded.
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RPM found in directory: /packages/linux-pbone/ftp5.gwdg.de/pub/opensuse/repositories/devel:/languages:/perl/openSUSE_Tumbleweed/noarch |