What is CICS BIF DIGEST command used for?

CICS BIF DIGEST is used to generate data digests and compute hash values, providing cryptographic capabilities, data integrity checking, and hash computation for CICS applications.

What types of digest algorithms are available?

Digest types include MD5 digest (hash, checksum, fingerprint, validation), SHA digest (SHA-1, SHA-256, SHA-512), CRC digest (CRC-32, CRC-16), and custom digest algorithms.

How do I handle errors with CICS BIF DIGEST?

Always check the response code and implement appropriate error handling, including validation of digest requests, retry mechanisms for failed operations, and fallback procedures for digest errors.

What is the purpose of data digest generation?

Digest generation enables data integrity checking, tamper detection, corruption detection, security applications, password hashing, digital signatures, and authentication in CICS applications.

When should I use CICS BIF DIGEST?

Use this command when you need to generate hash values, check data integrity, create digital fingerprints, implement security features, or validate data authenticity in CICS applications.

CICS BIF DIGEST - Data Digest and Hashing

CICS BIF DIGEST provides data digest and hashing capabilities for programs and transactions. It enables programs to generate data digests, compute hash values, and handle data digest operations in CICS environments.

What is CICS BIF DIGEST?

CICS BIF DIGEST is a Built-In Function (BIF) that allows programs to generate data digests and compute hash values. It provides cryptographic capabilities, data integrity checking, and hash computation for CICS applications.

Command Syntax

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EXEC CICS BIF DIGEST
    FROM(data-area)
    LENGTH(data-length)
    INTO(digest-area)
    DIGESTLENGTH(digest-length)
    [ALGORITHM(algorithm-name)]
    [RESP(response-code)]
END-EXEC

Parameters

Required Parameters

FROM(data-area) - Data area containing data to digest
LENGTH(data-length) - Length of data to digest
INTO(digest-area) - Area to receive digest value
DIGESTLENGTH(digest-length) - Length of digest area

Optional Parameters

ALGORITHM(algorithm-name) - Digest algorithm to use
RESP(response-code) - Response code variable

Digest Types

MD5 Digest

MD5 hash algorithm

• MD5 HASH - Generate MD5 hash
• MD5 CHECKSUM - Compute MD5 checksum
• MD5 FINGERPRINT - Create MD5 fingerprint
• MD5 VALIDATION - Validate MD5 hash

SHA Digest

SHA hash algorithms

• SHA-1 HASH - Generate SHA-1 hash
• SHA-256 HASH - Generate SHA-256 hash
• SHA-512 HASH - Generate SHA-512 hash
• SHA VALIDATION - Validate SHA hash

CRC Digest

CRC checksum algorithms

• CRC-32 CHECKSUM - Compute CRC-32 checksum
• CRC-16 CHECKSUM - Compute CRC-16 checksum
• CRC VALIDATION - Validate CRC checksum
• CRC ERROR DETECTION - Detect CRC errors

Custom Digest

Custom hash algorithms

• CUSTOM HASH - Generate custom hash
• CUSTOM CHECKSUM - Compute custom checksum
• CUSTOM FINGERPRINT - Create custom fingerprint
• CUSTOM VALIDATION - Validate custom hash

Programming Examples

Basic Data Digest

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. DIGEST01.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  INPUT-DATA      PIC X(100) VALUE 'Hello World'.
       01  DATA-LENGTH     PIC S9(8) COMP VALUE 100.
       01  DIGEST-AREA     PIC X(32).
       01  DIGEST-LENGTH   PIC S9(8) COMP VALUE 32.
       01  RESPONSE-CODE   PIC S9(8) COMP.
       01  DIGEST-NEEDED  PIC X(1) VALUE 'Y'.
       
       PROCEDURE DIVISION.
           IF DIGEST-NEEDED = 'Y'
               DISPLAY 'Generating data digest...'
               
               EXEC CICS BIF DIGEST
                   FROM(INPUT-DATA)
                   LENGTH(DATA-LENGTH)
                   INTO(DIGEST-AREA)
                   DIGESTLENGTH(DIGEST-LENGTH)
                   RESP(RESPONSE-CODE)
               END-EXEC
               
               IF RESPONSE-CODE = DFHRESP(NORMAL)
                   DISPLAY 'Digest generated successfully'
                   DISPLAY 'Input data: ' INPUT-DATA(1:DATA-LENGTH)
                   DISPLAY 'Digest: ' DIGEST-AREA(1:DIGEST-LENGTH)
               ELSE
                   DISPLAY 'Failed to generate digest'
               END-IF
           ELSE
               DISPLAY 'No digest needed'
           END-IF
           
           EXEC CICS RETURN END-EXEC.

Advanced Digest Generation

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. DIGEST02.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  INPUT-DATA      PIC X(200) VALUE 'Sample data for digest'.
       01  DATA-LENGTH     PIC S9(8) COMP VALUE 200.
       01  MD5-DIGEST      PIC X(16).
       01  SHA256-DIGEST   PIC X(32).
       01  CRC32-DIGEST    PIC X(4).
       01  DIGEST-LENGTH   PIC S9(8) COMP VALUE 32.
       01  RESPONSE-CODE   PIC S9(8) COMP.
       01  ALGORITHM-TYPE PIC X(10).
       01  DIGEST-COUNT   PIC S9(2) COMP VALUE 0.
       
       PROCEDURE DIVISION.
           PERFORM GENERATE-MD5-DIGEST
           PERFORM GENERATE-SHA256-DIGEST
           PERFORM GENERATE-CRC32-DIGEST
           
           EXEC CICS RETURN END-EXEC.
       
       GENERATE-MD5-DIGEST.
           MOVE 'MD5' TO ALGORITHM-TYPE
           MOVE 16 TO DIGEST-LENGTH
           
           EXEC CICS BIF DIGEST
               FROM(INPUT-DATA)
               LENGTH(DATA-LENGTH)
               INTO(MD5-DIGEST)
               DIGESTLENGTH(DIGEST-LENGTH)
               ALGORITHM(ALGORITHM-TYPE)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               ADD 1 TO DIGEST-COUNT
               DISPLAY 'MD5 Digest: ' MD5-DIGEST(1:DIGEST-LENGTH)
           END-IF.
       
       GENERATE-SHA256-DIGEST.
           MOVE 'SHA256' TO ALGORITHM-TYPE
           MOVE 32 TO DIGEST-LENGTH
           
           EXEC CICS BIF DIGEST
               FROM(INPUT-DATA)
               LENGTH(DATA-LENGTH)
               INTO(SHA256-DIGEST)
               DIGESTLENGTH(DIGEST-LENGTH)
               ALGORITHM(ALGORITHM-TYPE)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               ADD 1 TO DIGEST-COUNT
               DISPLAY 'SHA256 Digest: ' SHA256-DIGEST(1:DIGEST-LENGTH)
           END-IF.
       
       GENERATE-CRC32-DIGEST.
           MOVE 'CRC32' TO ALGORITHM-TYPE
           MOVE 4 TO DIGEST-LENGTH
           
           EXEC CICS BIF DIGEST
               FROM(INPUT-DATA)
               LENGTH(DATA-LENGTH)
               INTO(CRC32-DIGEST)
               DIGESTLENGTH(DIGEST-LENGTH)
               ALGORITHM(ALGORITHM-TYPE)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           IF RESPONSE-CODE = DFHRESP(NORMAL)
               ADD 1 TO DIGEST-COUNT
               DISPLAY 'CRC32 Digest: ' CRC32-DIGEST(1:DIGEST-LENGTH)
           END-IF.
       
       DISPLAY-RESULTS.
           DISPLAY 'Total digests generated: ' DIGEST-COUNT.

Error Handling with Digest Generation

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. DIGEST03.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  INPUT-DATA      PIC X(50) VALUE 'Test data for digest'.
       01  DATA-LENGTH     PIC S9(8) COMP VALUE 50.
       01  DIGEST-AREA     PIC X(32).
       01  DIGEST-LENGTH   PIC S9(8) COMP VALUE 32.
       01  RESPONSE-CODE   PIC S9(8) COMP.
       01  RETRY-COUNT    PIC S9(2) COMP VALUE 0.
       01  MAX-RETRIES    PIC S9(2) COMP VALUE 3.
       
       PROCEDURE DIVISION.
           PERFORM DIGEST-WITH-ERROR-HANDLING
           
           EXEC CICS RETURN END-EXEC.
       
       DIGEST-WITH-ERROR-HANDLING.
           PERFORM GENERATE-DIGEST
           
           IF RESPONSE-CODE NOT = DFHRESP(NORMAL)
               AND RETRY-COUNT < MAX-RETRIES
               ADD 1 TO RETRY-COUNT
               DISPLAY 'Retry ' RETRY-COUNT ' generating digest'
               PERFORM DIGEST-WITH-ERROR-HANDLING
           END-IF.
       
       GENERATE-DIGEST.
           EXEC CICS BIF DIGEST
               FROM(INPUT-DATA)
               LENGTH(DATA-LENGTH)
               INTO(DIGEST-AREA)
               DIGESTLENGTH(DIGEST-LENGTH)
               RESP(RESPONSE-CODE)
           END-EXEC
           
           EVALUATE RESPONSE-CODE
               WHEN DFHRESP(NORMAL)
                   DISPLAY 'Digest generated successfully'
               WHEN DFHRESP(INVREQ)
                   DISPLAY 'Invalid digest request'
               WHEN DFHRESP(LENGERR)
                   DISPLAY 'Data length error'
               WHEN DFHRESP(ALGORITHMERR)
                   DISPLAY 'Algorithm error'
               WHEN DFHRESP(DIGESTERR)
                   DISPLAY 'Digest generation error'
               WHEN OTHER
                   DISPLAY 'Unexpected error occurred'
           END-EVALUATE.

Digest Management

Digest Generation

• Hash Computation - Compute hash values
• Checksum Generation - Generate checksums
• Fingerprint Creation - Create data fingerprints
• Digest Validation - Validate digest values

Data Integrity

• Integrity Checking - Check data integrity
• Tamper Detection - Detect data tampering
• Corruption Detection - Detect data corruption
• Validation Verification - Verify data validation

Security Applications

• Password Hashing - Hash passwords securely
• Digital Signatures - Create digital signatures
• Authentication - Authenticate data
• Encryption Support - Support encryption operations

Error Recovery

• Error Detection - Detect digest errors
• Error Recovery - Recover from digest errors
• Retry Mechanisms - Implement retry logic
• Fallback Procedures - Use fallback procedures

Error Handling

Common Response Codes

DFHRESP(NORMAL) - Digest generated successfully
DFHRESP(INVREQ) - Invalid digest request
DFHRESP(LENGERR) - Data length error
DFHRESP(ALGORITHMERR) - Algorithm error
DFHRESP(DIGESTERR) - Digest generation error
DFHRESP(NOTAUTH) - Not authorized to generate digest

Performance Considerations

Digest Efficiency

• Optimize digest operations - Use efficient digest algorithms
• Minimize digest overhead - Reduce digest processing overhead
• Use appropriate algorithms - Choose appropriate digest methods
• Monitor digest frequency - Track digest occurrence patterns

System Impact

• Monitor system impact - Track how digests affect the system
• Optimize digest handling - Ensure efficient digest processing
• Manage resource usage - Monitor resource consumption
• Track performance metrics - Monitor digest handling performance

Best Practices

Digest Generation Best Practices

• Use appropriate digest algorithms for your needs
• Implement proper error handling for digest operations
• Validate digest results after generation
• Use secure algorithms for sensitive data
• Monitor digest generation performance
• Maintain digest audit trails
• Handle digest errors gracefully

Explain It Like I'm 5 Years Old

Think of CICS BIF DIGEST like making a fingerprint:

• Your Hand: "Put your hand on the paper" - Input data
• Make Fingerprint: "Press your hand down to make a fingerprint" - Generate digest
• Unique Pattern: "Your fingerprint is unique and special" - Unique hash
• Check It: "You can use it to prove it's really you" - Verify identity
• Keep It Safe: "Keep your fingerprint safe" - Secure the digest

Exercises

Exercise 1: Basic Digest Generation

Create a program that generates MD5 and SHA-256 digests for sample data.

Exercise 2: Advanced Digest Operations

Write a program that generates different types of digests and compares them.

Exercise 3: Error Handling

Implement comprehensive error handling for digest generation failures.

CICS BIF DIGEST - Data Digest and Hashing

What is CICS BIF DIGEST?

Command Syntax

Parameters

Required Parameters

Optional Parameters

Digest Types

MD5 Digest

SHA Digest

CRC Digest

Custom Digest

Programming Examples

Basic Data Digest

Advanced Digest Generation

Error Handling with Digest Generation

Digest Management

Digest Generation

Data Integrity

Security Applications

Error Recovery

Error Handling

Common Response Codes

Performance Considerations

Digest Efficiency

System Impact

Best Practices

Digest Generation Best Practices

Explain It Like I'm 5 Years Old

Exercises

Exercise 1: Basic Digest Generation

Exercise 2: Advanced Digest Operations

Exercise 3: Error Handling

Related Concepts

Cryptography

Data Integrity

Hash Functions

Built-In Functions

Error Handling

Related Pages