# RXS_Crypt()

This subprocedure performs cryptographic operations like hashing and encryption. Currently supported operations are:

* MD5
* SHA1
* SHA256
* SHA384
* SHA512

## Subprocedure Prototype

### IBM i 7.1+

| Field | Description |
|---|---|
| `     D RXS_Crypt...      D                 PR                  Extproc('RXS_Crypt') Opdesc      D                                     Like(RXS_Var16Mv_t)      D                                     Rtnparm` | Returns the output of the specified hashing/crytographic operation is returned. |
| `     D   Input                             Like(RXS_Var16Mv_t) Const      D                                     Options(*Varsize)` | Field to hold the input of the selected hashing/crytographic operation. You can pass a field smaller than 16M without any additional effort. |
| `     D   DS                                Like(RXS_Var64K_t)      D                                     Options(*Varsize)` | Holds settings which control how RXS_Crypt operates. This parm can accomodate a number of possible data structures, listed below. |


### IBM i 6.1

| Field | Description |
|---|---|
| `     D RXS_Crypt...      D                 PR                  Extproc('RXS_Crypt') Opdesc` |  |
| `     D   Output                            Like(RXS_Var16Mv_t)      D                                     Options(*Varsize)` | Field to hold the output of the selected hashing/crytographic operation. Note that if you pass a field smaller than 16M, you will need to specify the length of the Output in the subfield OutputLength. |
| `     D   Input                             Like(RXS_Var16Mv_t) Const      D                                     Options(*Varsize)` | Field to hold the input of the selected hashing/crytographic operation. You can pass a field smaller than 16M without any additional effort. |
| `     D   DS                                Like(RXS_Var64K_t)      D                                     Options(*Varsize)` | Holds settings which control how RXS_Crypt operates. This parm can accomodate a number of possible data structures, listed below. |


## Example Code

### IBM i 7.1+

#### Example 1: MD5 Hash of Character Field
```rpgle
      *--------------------------------------------------------------
      * This example code calculates an MD5 hash from a character field.
      *--------------------------------------------------------------
     H DFTACTGRP(*NO) BNDDIR('RXSBND') ACTGRP(*CALLER)

      /copy QRPGLECPY,RXSCB

     D HashMD5DS       DS                  LikeDS(RXS_MD5CryptDS_t)
     D Data            S                   Like(RXS_Var1Kv_t)
     D Hash            S                   Like(RXS_Var1Kv_t)
      /free
        Data = 'Hello World';

        RXS_ResetDS( HashMD5DS : RXS_DS_TYPE_MD5CRYPT );
        Hash = RXS_Crypt( Data : HashMD5DS );

        RXS_JobLog( 'Hash: %s' : Hash ); // Output: Hash: B10A8DB164E0754105B7A99BE72E3FE5

        *INLR = *ON;
      /end-free
```

### IBM i 6.1

#### Example 1: MD5 Hash of Character Field
```rpgle
      *--------------------------------------------------------------
      * This example code calculates an MD5 hash from a character field.
      *--------------------------------------------------------------
     H DFTACTGRP(*NO) BNDDIR('RXSBND') ACTGRP(*CALLER)

      /define RXSV6R1
      /copy QRPGLECPY,RXSCB

     D HashMD5DS       DS                  LikeDS(RXS_MD5CryptDS_t)
     D Data            S                   Like(RXS_Var1Kv_t)
     D Hash            S                   Like(RXS_Var1Kv_t)
      /free
        Data = 'Hello World';

        RXS_ResetDS( HashMD5DS : RXS_DS_TYPE_MD5CRYPT );
        RXS_Crypt( Hash : Data : HashMD5DS );

        RXS_JobLog( 'Hash: %s' : Hash ); // Output: Hash: B10A8DB164E0754105B7A99BE72E3FE5

        *INLR = *ON;
      /end-free
```

## Data Structures

### RXS_MD5CryptDS_t

| Field | Description |
|---|---|
| `     D RXS_MD5CryptDS_t...      D                 DS                  Qualified Template Inz` |  |
| `     D   ReturnedErrorInfo...      D                                     LikeDS(RXS_ReturnedErrorInfoDS_t) Inz` |  |
| `     D   OnErrorMessageType...      D                               10I 0` |  |
| `     D   InputStmf                         Like(RXS_Var1Kv_t)` | Optional IFS stream file to use as input data for hash operation. |
| `     D   InputCcsid                  10I 0 Inz(RXS_CCSID_JOB)` | CCSID of input data. Used when the input data is of a different CCSID of the job CCSID. Not necessary if using InputStmf. |
| `     D   EncryptAsCcsid...      D                               10I 0 Inz(RXS_CCSID_ISO88591)` | CCSID to convert the input data into before hashing. Note that this is typically going to be RXS_CCSID_ISO88591 or RXS_CCSID_UTF8. |
| `     D   InputPointer...      D                                 *` | **Internal use only** |
| `     D   InputLength                 10I 0` | **Internal use only** |
| `     D   OutputPointer...      D                                 *` | **Internal use only** |
| `     D   OutputLength                10I 0` | **Internal use only** |
| `     D   Reserved                  2048A` | **Internal use only** |


### RXS_SHACryptDS_t

| Field | Description |
|---|---|
| `     D RXS_SHACryptDS_t...      D                 DS                  Qualified Template Inz` |  |
| `     D   ReturnedErrorInfo...      D                                     LikeDS(RXS_ReturnedErrorInfoDS_t) Inz` |  |
| `     D   OnErrorMessageType...      D                               10I 0` |  |
| `     D   Algorithm                    4P 3` | Determines which SHA algorithm/block size to use when hashing. **Valid Values:** `RXS_CRYPT_SHA1_ALGORITHM`, `RXS_CRYPT_SHA256_ALGORITHM`, `RXS_CRYPT_SHA384_ALGORITHM`, `RXS_CRYPT_SHA512_ALGORITHM` |
| `     D   InputStmf                         Like(RXS_Var1Kv_t)` | Optional IFS stream file to use as input data for hash operation. |
| `     D   InputCcsid                  10I 0 Inz(RXS_CCSID_JOB)` | CCSID of input data. Used when the input data is of a different CCSID of the job CCSID. Not necessary if using InputStmf. |
| `     D   EncryptAsCcsid...      D                               10I 0 Inz(RXS_CCSID_ISO88591)` | CCSID to convert the input data into before hashing. Note that this is typically going to be RXS_CCSID_ISO88591 or RXS_CCSID_UTF8. |
| `     D   InputPointer...      D                                 *` | **Internal use only** |
| `     D   InputLength                 10I 0` | **Internal use only** |
| `     D   OutputPointer...      D                                 *` | **Internal use only** |
| `     D   OutputLength                10I 0` | **Internal use only** |
| `     D   Reserved                  2049A` | **Internal use only** |