Function: fhash

Syntax

fhash (<file> {,<password> {,<algorithm>}})

Type

string

Returns

A derived fingerprint (hash value) for a file.

Various algorithms are available for computing hash values, and the fingerprint may be encrypted via a supplied password.

Fingerprints are text strings of hexadecimal numeric sequences. Different algorithms generate different fingerprint string lengths.

Parameters

• <file>
  The name of the file for which a fingerprint (hash value) is to be derived. The file must exist.

• <password>
  A password to encrypt the hash value. If this omitted, or null, no encryption is performed.

• <algorithm>
  The hashing algorithm to be used. This is a numeric parameter with a value from the following table. If omitted, the value 3 (SHA1/160) is assumed.

Value	Algorithm	Value String Length	Details
0	CRC16	4	Cyclic Redundancy Check (2-byte)
1	CRC32	8	Cyclic Redundancy Check (4-byte)
2	MD5	32	Message Digest
3*	SHA1/160	40	Secure Hash Algorithm (160-bit)
4	SHA2/256	64	Secure Hash Algorithm (256-bit)
5	SHA2/384	96	Secure Hash Algorithm (384-bit)
6	SHA2/512	128	Secure Hash Algorithm (512-bit)

* - the default algorithm

Examples

The following would return a 32-character password-encrypted string MD5 value.

string myhash = fhash(myfile,'toblerone',2)