Open Profile Compression
The supported compression method is the gzip deflate algorithm (RFC1951). The gzip utility and the
compression library that implements the same algorithm (zlib) are available from Internet sites.
To identify compression, the phone expects the compressed file to contain a gzip compatible header. Invocation
of the gzip utility on the original Open profile generates the header. The phone inspects the downloaded file
header to determine the file format.
For example, if profile.xml is a valid profile, the file profile.xml.gz is also accepted. Either of the following
commands can generate this profile type:
•
>gzip profile.xml
Replaces original file with compressed file.
•
>cat profile.xml | gzip > profile.xml.gz
Leaves original file in place, produces new compressed file.
A tutorial on compression is provided in the Compress an Open Profile with Gzip, on page 58 section.
Related Topics
Compress an Open Profile with Gzip, on page 58
Open Profile Encryption with AES
Symmetric key encryption can be used to encrypt an Open configuration profile, whether the file is compressed
or not. The supported encryption algorithm is the American Encryption Standard (AES), using 256-bit keys,
applied in cipher block chaining mode.
Compression must precede encryption for the phone to recognize a compressed and encrypted Open format
profile. Encrypt a Profile with OpenSSL, on page 59 provides a tutorial on encryption.
Note
The OpenSSL encryption tool, available for download from various Internet sites, can perform the encryption.
Support for 256-bit AES encryption may require recompilation of the tool to enable the AES code. The
firmware has been tested against version openssl-0.9.7c.
For an encrypted file, the profile expects the file to have the same format as generated by the following
command:
# example encryption key = SecretPhrase1234
openssl enc –e –aes-256-cbc –k SecretPhrase1234 –in profile.xml –out profile.cfg
# analogous invocation for a compressed xml file
openssl enc –e –aes-256-cbc –k SecretPhrase1234 –in profile.xml.gz –out profile.cfg
A lowercase -k precedes the secret key, which can be any plain text phrase, and which is used to generate a
random 64-bit salt. With the secret specified by the -k argument, the encryption tool derives a random 128-bit
initial vector and the actual 256-bit encryption key.
Cisco IP Phone 6800 Series Multiplatform Phones Provisioning Guide
16
Provisioning Scripts
Open Profile Compression
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