HASH

A one-way hash function (HASH) takes a variable-length input string and converts it into a fixed-length (usually smaller) output called a hash value. The hash value serves as a unique identifier for the input data, similar to a fingerprint. You can use the hash value to verify whether the data has been altered.

Since it is easy to compute a hash value from input data but difficult to generate the original data from the hash value, one-way hash functions are effective in ensuring data integrity.

Syntax

DBMS_CRYPTO.Hash (
   src IN RAW,
   typ IN PLS_INTEGER)
 RETURN RAW;

DBMS_CRYPTO.Hash (
   src IN BLOB,
   typ IN PLS_INTEGER)
 RETURN RAW;

DBMS_CRYPTO.Hash (
   src IN CLOB CHARACTER SET ANY_CS,
   typ IN PLS_INTEGER)
 RETURN RAW;

Parameters

Considerations

We recommend that you use SHA-1 or SHA-2, which are more resistant to brute-force attacks than MD4 or MD5. If you must use the Message Digest algorithm, MD5 provides higher security than MD4.