perl-Tie-EncryptedHash -- Hashes (and objects based on hashes) with encrypting fields<hr>
<a href="http://search.cpan.org/dist/Tie-EncryptedHash/">http://search.cpan.org/dist/Tie-EncryptedHash/</a><hr>
Tie::EncryptedHash augments Perl hash semantics to build secure,
encrypting containers of data. Tie::EncryptedHash introduces special
hash fields that are coupled with encrypt/decrypt routines to encrypt
assignments at STORE() and decrypt retrievals at FETCH(). By design,
encrypting fields are associated with keys that begin in single
underscore. The remaining keyspace is used for accessing normal hash
fields, which are retained without modification.

While the password is set, a Tie::EncryptedHash behaves exactly like a
standard Perl hash. This is its transparent mode of access. Encrypting
and normal fields are identical in this mode. When password is
deleted, encrypting fields are accessible only as ciphertext. This is
Tie::EncryptedHash's opaque mode of access, optimized for serialization.

Encryption is done with Crypt::CBC(3), which encrypts in the cipher
block chaining mode with Blowfish, DES or IDEA. Tie::EncryptedHash uses
Blowfish by default, but can be instructed to employ any cipher supported
by Crypt::CBC(3).
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