Sample code

This program creates a simple XML document with the string to hash as text of the root node called ROOT.

Then uses the security.Digest API to compute a XML digital signature for the content of the root node, or in other words the string you wish to hash, using a XPath expression.

And finally, retrieves the hash value from the signature and returns it.

The computed hash value is encoded in Base64, so you may have additional conversion to do.

IMPORT SECURITY

MAIN

  DEFINE result STRING

  IF NUM_ARGS() != 2 THEN
    DISPLAY "Usage: ComputeHash <string> <hashcode>"
    DISPLAY "  string: the string to digest"
    DISPLAY "  hashcode: SHA1, SHA512, SHA384, SHA256, SHA224, MD5"
  ELSE
    LET result = ComputeHash(ARG_VAL(1), ARG_VAL(2))
    IF result IS NOT NULL THEN
      DISPLAY "Hash value is: ",result
    ELSE
      DISPLAY "Error"
    END IF
  END IF

END MAIN

FUNCTION ComputeHash(toDigest, algo)

  DEFINE toDigest, algo, result STRING
  DEFINE dgst security.Digest

  TRY
    LET dgst = security.Digest.CreateDigest(algo)
    CALL dgst.AddStringData(toDigest)
    LET result = dgst.DoBase64Digest()
  CATCH
    DISPLAY "ERROR : ", STATUS, " - ", SQLCA.SQLERRM
    EXIT PROGRAM(-1)
  END TRY

  RETURN result
END FUNCTION

Example of usage:

$ fglrun ComputeHash "Hello, world !!!" SHA1

$ Hash value is: Ck1VqNd45QIvq3AZd8XYQLvEhtA=