Re: decrypt.rb
Aki, I just used the "EC key" instructions from the Dovecot MailCrypt wiki: https://wiki.dovecot.org/Plugins/MailCrypt " In order to generate an EC key, you must first choose a curve from the output of this command: > openssl ecparam -list_curves If you choose the curve prime256v1, generate and EC key with the command: > openssl ecparam -name prime256v1 -genkey | openssl pkey -out ecprivkey.pem Then generate a public key out of your private EC key > openssl pkey -in ecprivkey.pem -pubout -out ecpubkey.pem " -Dave I'm going on a limb and guess that there is something strange happening with ruby and openssl versions here. The main point of the script is to show how the data can be decrypted, and can be used for small-scale data recovery as well. Aki Copy that. I would agree that it seems to be something weird between OpenSSL and Ruby in this case. Since I'm able to get it to work in my specific instance, and since it doesn't seem systemic outside of my situation, I'd say -- specific problem solved! :) Thanks for your help. -Dave
Re: decrypt.rb
> On 11 April 2019 17:44 David Salisbury via dovecot > wrote: > > > On 4/11/2019 1:50 AM, Aki Tuomi wrote: > > > >> ... > >> So, not being an expert at encryption, what are the ramifications of > >> those digests being read as different values in the two different > >> places?? I do notice that the get_pubid_priv() function is internal to > >> the decrypt.rb script and calls several OpenSSL functions. > >> > >> -Dave > > Hmm... can you show me how you made the keypair for encryption? Maybe there > > is some difference? > > > > Aki > > > > Aki, I just used the "EC key" instructions from the Dovecot MailCrypt wiki: > https://wiki.dovecot.org/Plugins/MailCrypt > > " > In order to generate an EC key, you must first choose a curve from the > output of this command: > > openssl ecparam -list_curves > > If you choose the curve prime256v1, generate and EC key with the command: > > openssl ecparam -name prime256v1 -genkey | openssl pkey -out > ecprivkey.pem > > Then generate a public key out of your private EC key > > openssl pkey -in ecprivkey.pem -pubout -out ecpubkey.pem > " > > -Dave I'm going on a limb and guess that there is something strange happening with ruby and openssl versions here. The main point of the script is to show how the data can be decrypted, and can be used for small-scale data recovery as well. Aki
Re: decrypt.rb
On 4/11/2019 1:50 AM, Aki Tuomi wrote: ... So, not being an expert at encryption, what are the ramifications of those digests being read as different values in the two different places?? I do notice that the get_pubid_priv() function is internal to the decrypt.rb script and calls several OpenSSL functions. -Dave Hmm... can you show me how you made the keypair for encryption? Maybe there is some difference? Aki Aki, I just used the "EC key" instructions from the Dovecot MailCrypt wiki: https://wiki.dovecot.org/Plugins/MailCrypt " In order to generate an EC key, you must first choose a curve from the output of this command: > openssl ecparam -list_curves If you choose the curve prime256v1, generate and EC key with the command: > openssl ecparam -name prime256v1 -genkey | openssl pkey -out ecprivkey.pem Then generate a public key out of your private EC key > openssl pkey -in ecprivkey.pem -pubout -out ecpubkey.pem " -Dave
Re: decrypt.rb
> On 11 April 2019 00:49 David Salisbury via dovecot
> wrote:
>
>
> >>>
> >> Yes. I gave it a try here, and it seems to work. Does it give any extra
> >> information if you include -i flag?
> >>
> >> Aki
> >>
> >
> > Yes, I had tried that, and it doesn't give much extra information, at
> > least to my eye, that seems to help my issue. Above the previous
> > output it outputs the Version, Flags, Header length, Cipher algo, and
> > Digest algo, and then the Key derivation Rounds. Then it does the
> > previous output and exits as before.
> >
> > I tried using pry to debug through the script a little, and strace as
> > well, but have not found anything pointing me in the direction of a
> > solution or what may be causing it not to work for me yet. Will keep
> > looking.
> >
> > Out of curiosity, what version of ruby were you using to run the
> > script? My ruby version is 2.5.1p57.
> >
> > -Dave
>
> So, I found that in decrypt.rb there is a point where this section is
> reached:
>
> [code]
> unless our_key == nil
> # decrypt data!
> [/code]
>
> While testing I discovered that, for me, our_key was apparently equal to
> nil because the code was never even making it into that block. There
> was a block right above that that was setting our_key to nil if a
> certain condition happened, but I could tell that condition wasn't
> happening as the accompanying error message wasn't printing. Looking
> farther up, I found:
>
> [code]
> our_key = key if key[:digest] == options[:key_digest]
> [/code]
>
> I printed the values of key[:digest] and options[:key_digest], and they
> are in fact different. Since our_key is nil by default, our_key was
> just remaining nil, hence no decryption for me.
>
> The key[:digest] variable is filled a little above that part of the code:
>
> [code]
> (key[:type],key[:digest]) = options[:input].read(33).unpack('Ca*')
> [/code]
>
> and options[:key_digest] is filled as the private key option is passed in:
>
> [code]
> opts.on("-k","--key KEY", "Private key to decrypt file") do |k|
> options[:key] = OpenSSL::PKey.read(File.open(k))
> options[:key_digest] = get_pubid_priv(options[:key])
> end
> [/code]
>
> It's apparently using the key from the command line to get the key
> digest with the get_pubid_priv() function, and for some reason that
> value is coming back as different than the key digest that is
> ascertained by the "options[:input].read" line.
>
> Out of curiosity, and since I know I'm using the correct key, I
> commented out the if statement in the our_key line so as not to make the
> comparison between the digests:
>
> [code]
> our_key = key #if key[:digest] == options[:key_digest]
> [/code]
>
> and then it worked! The script successfully decrypted the message!
>
> So, not being an expert at encryption, what are the ramifications of
> those digests being read as different values in the two different
> places?? I do notice that the get_pubid_priv() function is internal to
> the decrypt.rb script and calls several OpenSSL functions.
>
> -Dave
Hmm... can you show me how you made the keypair for encryption? Maybe there is
some difference?
Aki
Re: decrypt.rb
Yes. I gave it a try here, and it seems to work. Does it give any extra
information if you include -i flag?
Aki
Yes, I had tried that, and it doesn't give much extra information, at
least to my eye, that seems to help my issue. Above the previous
output it outputs the Version, Flags, Header length, Cipher algo, and
Digest algo, and then the Key derivation Rounds. Then it does the
previous output and exits as before.
I tried using pry to debug through the script a little, and strace as
well, but have not found anything pointing me in the direction of a
solution or what may be causing it not to work for me yet. Will keep
looking.
Out of curiosity, what version of ruby were you using to run the
script? My ruby version is 2.5.1p57.
-Dave
So, I found that in decrypt.rb there is a point where this section is
reached:
[code]
unless our_key == nil
# decrypt data!
[/code]
While testing I discovered that, for me, our_key was apparently equal to
nil because the code was never even making it into that block. There
was a block right above that that was setting our_key to nil if a
certain condition happened, but I could tell that condition wasn't
happening as the accompanying error message wasn't printing. Looking
farther up, I found:
[code]
our_key = key if key[:digest] == options[:key_digest]
[/code]
I printed the values of key[:digest] and options[:key_digest], and they
are in fact different. Since our_key is nil by default, our_key was
just remaining nil, hence no decryption for me.
The key[:digest] variable is filled a little above that part of the code:
[code]
(key[:type],key[:digest]) = options[:input].read(33).unpack('Ca*')
[/code]
and options[:key_digest] is filled as the private key option is passed in:
[code]
opts.on("-k","--key KEY", "Private key to decrypt file") do |k|
options[:key] = OpenSSL::PKey.read(File.open(k))
options[:key_digest] = get_pubid_priv(options[:key])
end
[/code]
It's apparently using the key from the command line to get the key
digest with the get_pubid_priv() function, and for some reason that
value is coming back as different than the key digest that is
ascertained by the "options[:input].read" line.
Out of curiosity, and since I know I'm using the correct key, I
commented out the if statement in the our_key line so as not to make the
comparison between the digests:
[code]
our_key = key #if key[:digest] == options[:key_digest]
[/code]
and then it worked! The script successfully decrypted the message!
So, not being an expert at encryption, what are the ramifications of
those digests being read as different values in the two different
places?? I do notice that the get_pubid_priv() function is internal to
the decrypt.rb script and calls several OpenSSL functions.
-Dave
Re: decrypt.rb
On 4/10/2019 1:32 AM, Aki Tuomi wrote:
On 9.4.2019 18.15, Dave wrote:
I've tried specifying an output file as well, per the script's
command line options,
but the output file is 0 bytes. Does anyone have any suggestions?
I *think* I'm
using it the way it's intended to be used, but maybe I'm not?!
-Dave
Hi!
Maybe the key you tried was not used to encrypt the file?
Aki
Aki, it's the same key I've used in the config for the mail_crypt
plugin in 90-plugin.conf:
plugin {
mail_crypt_global_private_key = <[PATH_TO_PRIVATE_KEY]
mail_crypt_global_public_key = <[PATH_TO_PUBLIC_KEY]
mail_crypt_save_version = 2
}
That's the private key that's encrypting all of the messages
successfully, so that's the one I would use with script, correct?
-Dave
Yes. I gave it a try here, and it seems to work. Does it give any extra
information if you include -i flag?
Aki
Yes, I had tried that, and it doesn't give much extra information, at
least to my eye, that seems to help my issue. Above the previous output
it outputs the Version, Flags, Header length, Cipher algo, and Digest
algo, and then the Key derivation Rounds. Then it does the previous
output and exits as before.
I tried using pry to debug through the script a little, and strace as
well, but have not found anything pointing me in the direction of a
solution or what may be causing it not to work for me yet. Will keep
looking.
Out of curiosity, what version of ruby were you using to run the
script? My ruby version is 2.5.1p57.
-Dave
Re: decrypt.rb
On 9.4.2019 18.15, Dave wrote:
> >> I've tried specifying an output file as well, per the script's
> command line options,
> >> but the output file is 0 bytes. Does anyone have any suggestions?
> I *think* I'm
> >> using it the way it's intended to be used, but maybe I'm not?!
> >> -Dave
> >
> > Hi!
> > Maybe the key you tried was not used to encrypt the file?
> > Aki
>
> Aki, it's the same key I've used in the config for the mail_crypt
> plugin in 90-plugin.conf:
>
> plugin {
> mail_crypt_global_private_key = <[PATH_TO_PRIVATE_KEY]
> mail_crypt_global_public_key = <[PATH_TO_PUBLIC_KEY]
> mail_crypt_save_version = 2
> }
>
> That's the private key that's encrypting all of the messages
> successfully, so that's the one I would use with script, correct?
> -Dave
>
Yes. I gave it a try here, and it seems to work. Does it give any extra
information if you include -i flag?
Aki
Re: decrypt.rb
>> I've tried specifying an output file as well, per the script's
command line options,
>> but the output file is 0 bytes. Does anyone have any suggestions?
I *think* I'm
>> using it the way it's intended to be used, but maybe I'm not?!
>> -Dave
>
> Hi!
> Maybe the key you tried was not used to encrypt the file?
> Aki
Aki, it's the same key I've used in the config for the mail_crypt plugin
in 90-plugin.conf:
plugin {
mail_crypt_global_private_key = <[PATH_TO_PRIVATE_KEY]
mail_crypt_global_public_key = <[PATH_TO_PUBLIC_KEY]
mail_crypt_save_version = 2
}
That's the private key that's encrypting all of the messages
successfully, so that's the one I would use with script, correct?
-Dave
Re: decrypt.rb
On 9.4.2019 2.33, Dave via dovecot wrote: > Per the Dovecot site here: > https://wiki.dovecot.org/Plugins/MailCrypt > ... the "decrypt.rb" ruby script can be used to decrypt a > Dovecot-encrypted message file from the command line. The script sort > of runs successfully for me, in the sense that it doesn't error out, > but it doesn't show the decrypted message. > > I've called it like so: > decrypt.rb -k -f ./encrypted_message > > But when I do it just displays the info below and exits (I've subbed > tags for the actual data): > > --[OUTPUT]--- > > Key(s) (total: 1) > - Key type : EC > - Key digest: > - Peer key : > - Encrypted : > - Kd hash : > > --- > > I've tried specifying an output file as well, per the script's command > line options, but the output file is 0 bytes. Does anyone have any > suggestions? I *think* I'm using it the way it's intended to be used, > but maybe I'm not?! > > -Dave > Hi! Maybe the key you tried was not used to encrypt the file? Aki
