SHA-512 is a variant within the Secure Hash Algorithms family of cryptographic hash functions. It was published as a Federal Information Processing Standard (FIPS) by the National Institute of Standards and Technology (NIST).
OPTIZMO has now added support for the storage and distribution of SHA-512 hashed email addresses in response to widespread adoption of this standard by the technology industry.
Like MD5, the SHA-512 is a one-way encoding, meaning that you cannot recover the original string from the hash. However, the SHA-512 hash algorithm addresses many of the shortfalls of MD5 such as collision resistance and lookup tables. It produces a 128 character hash - four times larger than the hash produced by the MD5 algorithm (32 characters).
When you download an Opt-Out List hashed using SHA-512, you must hash your local recipient email list in SHA-512 prior to comparing it against the Opt-Out List. As MD5 and SHA-512 are vastly different, any comparisons between the two will yield invalid results.
Example for verifying your SHA-512 algorithm
Output SHA-512 Hash
Output MD5 Hash