This patch allows the user to choose the strength of the
passphrase mangling during the process in which the key is
produced from the passphrase. It only affects symmetric
encryption.
Unmodified code that calls openpgp.SymmetricallyEncrypt() will
continue to get the now-default count of 65536. Otherwise, a
count in the range [1024, 65011712] may be configured. Illegal
values in and outside this range will silently be rounded up
to legal values within the said range.
The test to s2k.Serialize() has been modified to test a
variety of non-default counts with all the valid hashes and
ensure that the decoding component of s2k can parse and
decrypt the result.
Additional testing has been done with GPG to ensure that the
latter can parse and decrypt files encrypted/encoded with
various counts.
LGTM=agl
R=golang-codereviews, agl
CC=golang-codereviews
https://golang.org/cl/176080043
This patch implements the facilities needed to compress data before
encryption as allowed (and recommended) by RFC 4880. The new
functionality is then used to add support for compressing data during
symmetric encryption (openpgp.SymmetricallyEncrypt()).
For now, compression defaults to off. Also, only the ZIP and ZLIB
compression schemes are supported by this patch.
Resulting output tested/verified using GPG.
https://gist.github.com/marete/6189760 is a small program that can be
used to test that the output of various compression/encryption settings
can be read by GPG or other RFC 4880 programs.
Upon review, I will follow this patch with 2 others: a) Add support for compression during public key encryption (openpgp.Encrypt()) b) Enable
compression by default (subject to the restrictions of the "Compression Preferences" section in RFC 4880).
R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/12685044
Clear signed messages are often seen in email and are formatted so
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special tools.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5604043