What is a "passphrase?"

Introduction > What is a "passphrase?"

A passphrase, as the name suggests,  is like a password but can be a collection of words and can include spaces and punctuation characters.  Temprecord uses passphrase for two different purposes:

•As a key used to calculate a digest to include with Temprecord data files.  A digest, or "hash", is used to protect datafiles against tampering or damage.  This digest is calculated using the passphrase key you supply and the data in the file to produce a unique collection of characters that can only be produced with that combination of passphrase and data in the file.  A typical digest stored in the file might be:
 
  35ACEA2AC2B8D664411A8CD605EC101A1F7896EF5AAA824DA9C986FA12B8DC5D
 
If any part of the data in the file is changed, or the digest in the file is changed, then a new digest calculated using the data in the file and the same key will not agree with the digest in the file.

•To protect loggers against unauthorized modification.  Knowledge of the passphrase is required to reuse and program the loggers if a passphrase is assigned. Previous versions of Temprecord loggers could be protected with "passwords", although strictly speaking these were more like "PIN numbers", as they could only be numeric.  We now allow loggers to be protected with "passphrases".
 
The passphrase is not stored in the logger, rather the passphrase is used as a key to produce a hash digest and the digest is stored in the logger.
 

There are a few important facts to remember about passphrases:

•Case is significant, that is to say a passphrase of "Fred" is different from "fred".  It is for this reason that the Temprecord software will issue a specific warning if you enter an incorrect passphrase and you also have "Caps Lock" turned on.

• A passphrase can include spaces, but leading and trailing spaces are ignored.

•Characters past 32 are ignored.

•Only characters from the ASCII 7-bit character set are permitted.

•It is not possible (apart from a lucky guess) for anyone else (including Temprecord) to determine what passphrase has been used to protect a logger.  

Finally, anywhere in this help text you see the word "password", we mean "passphrase".