Encrypted data bags created with ruby 1.8.7 can be unreadable from ruby 1.9.3

First use rvm to install ruby-1.8.7-p370 and ruby-1.9.3-p194

Create a data bag source file as follows (make sure "foo" has the \n):

Generate a key:
openssl rand -base64 512 | tr -d '\r\n' > key

rvm use 1.8.7
knife data bag create test
knife data bag from file test test.json --secret-file key

Then switch to 1.9.3:
rvm use 1.9.3
knife data bag show test test --secret-file key -Fj
Output is:

Suspect that the issue is with the YAML Psych backend which is not able to decode YAML generated by 1.8.7.

$ rvm use 1.8.7
$ irb
1.8.7 :001 > require 'yaml'
1.8.7 :002 > YAML.dump("foo\n")
=> "--- |\nfoo\n\n"
1.8.7 :003 > quit
$ rvm use 1.9.3
$ irb
1.9.3p194 :001 > require 'yaml'
1.9.3p194 :002 > YAML.load("--- |\nfoo\n\n")
=> ""