Take the 2-minute tour ×  It appears that only Partial
Homomorphic Encryption(P.H.E.) is practical for modern day
(2011) use. However I'm having difficulty locating libraries
(FOSS or otherwise) that enable me to leverage this technology.
El Gamal is an example of an algorithm that does PHE, but the
wiki page doesn't clearly explain what blind math operations are
supported and how to implement them.  Potential Use Cases  A PHE
is something that can be used abstract to offload mathematic
operations to a 3rd without that party ever knowing what the
underlying value is. e.g. x+y=z can be performed and it will
have a valid encrypted result, but all 3 values are never known
in unencrypted format to the third party. This is beneficial to
protecting stock market analysis data, PII, or anything
considered proprietary or confidential.   So, what encryption
algorithms exist and what libraries exist that allow me to
operate on the encrypted data? Samples of operations I'm
interested in include    • Addition and Subtrac