Example in ILE RPG: Reading encrypted data from a file
See Scenario: Key Management and File Encryption Using the Cryptographic Services APIs for a description of this scenario.
Note: By using the code examples, you agree to the terms of the Code license and disclaimer information.
* Sample RPG program: bill_cus
*
* COPYRIGHT 5722-SS1, 5761-SS1 (c) IBM Corp 2004, 2008
*
* This material contains programming source code for your
* consideration. These examples have not been thoroughly
* tested under all conditions. IBM, therefore, cannot
* guarantee or imply reliability, serviceability, or function
* of these programs. All programs contained herein are
* provided to you "AS IS". THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* EXPRESSLY DISCLAIMED. IBM provides no program services for
* these programs and files.
*
* Description: This is a sample program to demonstrate use
* of the Cryptographic Services APIs. APIs demonstrated in
* this program are:
* Create Algorithm Context
* Create Key Context
* Decrypt Data
* Destroy Key Context
* Destroy Algorithm Context
*
* Function: For each record in the Customer Data file (CUSDTA),
* check the accounts receivable balance. If there is a balance
* decrypt the customers data and call bill_cus to create a bill.
* The customer data is encrypted with a file key kept in the
* Customer Processing Information file (CUSPI).
*
* Refer to the IBM® i Information Center for a full
* description of this scenario.
*
* Use the following command to compile this program:
* CRTRPGMOD MODULE(MY_LIB/BILL_CUS) SRCFILE(MY_LIB/QRPGLESRC)
*
H nomain bnddir('QC2LE')
Fcuspi uf e disk usropn
Fcusdta uf a e disk prefix(C) usropn
* System includes
D/Copy QSYSINC/QRPGLESRC,QUSEC
D/Copy QSYSINC/QRPGLESRC,QC3CCI
* Prototypes
DBill_Cus pr 10i 0 extproc('Bill_Cus')
DCreate_Bill pr 10i 0 extproc('Create_Bill')
D cusDta 1 const
D balance 10 2 value
DCrtAlgCtx pr extproc('Qc3CreateAlgorithmContext')
D algD 1 const
D algFormat 8 const
D AESctx 8
D errCod 1
DCrtKeyCtx pr extproc('Qc3CreateKeyContext')
D key 1 const
D keySize 10i 0 const
D keyFormat 1 const
D keyType 10i 0 const
D keyForm 1 const
D keyEncKey 8 const options(*omit)
D keyEncAlg 8 const options(*omit)
D keyTkn 8
D errCod 1
DDestroyKeyCtx pr extproc('Qc3DestroyKeyContext')
D keyTkn 8 const
D errCod 1
DDestroyAlgCtx pr extproc('Qc3DestroyAlgorithmContext')
D AESTkn 8 const
D errCod 1
DDecryptData pr extproc('Qc3DecryptData')
D encData 1 const
D encDataSize 10i 0 const
D algDesc 1 const
D algDescFmt 8 const
D keyDesc 1 const
D keyDescFmt 8 const
D csp 1 const
D cspDevNam 10 const options(*omit)
D clrDta 1
D clrLenPrv 10i 0 const
D clrLenRtn 10i 0
D errCod 1
DPrint pr 10i 0 extproc('printf')
D charString 1 const options(*nopass)
PBill_Cus b export
DBill_Cus pi 10i 0
* Local variable
D csp s 1 inz('0')
D error s 10i 0 inz(-1)
D ok s 10i 0 inz(0)
D rtn s 10i 0
D rtnLen s 10i 0
D plainLen s 10i 0
D cipherLen s 10i 0
D kekTkn s 8
D AESctx s 8
D KEKctx s 8
D FKctx s 8
D keySize s 10i 0
D keyType s 10i 0
D keyFormat s 1
D keyForm s 1
D inCusInfo s 80
D inCusNum s 8 0
D ECUSDTA s 80
C eval QUSBPRV = 0
* Create an AES algorithm context for the key-encrypting key (KEK)
C eval QC3D0200 = *loval
C eval QC3BCA = 22
C eval QC3BL = 16
C eval QC3MODE = '1'
C eval QC3PO = '0'
C callp CrtAlgCtx( QC3D0200 :'ALGD0200'
C :AESctx :QUSEC)
* Create a key context for the key-encrypting key (KEK)
C eval keySize = %size(QC3D040000)
C eval keyFormat = '0'
C eval keyType = 22
C eval keyForm = '0'
C eval QC3D040000 = *loval
C eval QC3KS00 = 'CUSKEYFILEMY_LIB'
C eval QC3RL = 'CUSDTAKEK'
C callp CrtKeyCtx( QC3D040000 :keySize :'4'
C :keyType :keyForm :*OMIT
C :*OMIT :KEKctx :QUSEC)
C
* Open CUSPI file
C open(e) cuspi
C if %error = '1'
C callp Print('Open of Customer Processing -
C Information File (CUSPI) failed')
C return error
C endif
* Read first (only) record to get encrypted file key
C read(e) cuspirec
C if %eof = '1'
C callp Print('Customer Processing Information -
C (CUSPI) record missing')
C close cuspi
C return error
C endif
C close cuspi
* Create a key context for the file key
C eval keySize = %size(KEY)
C eval keyFormat = '0'
C eval keyType = 22
C eval keyForm = '1'
C callp CrtKeyCtx( KEY :keySize :keyFormat
C :keyType :keyForm :KEKctx
C :AESctx :FKctx :QUSEC)
* Wipe out the encrypted file key value from program storage
C eval Key = *loval
* Open CUSDTA
C open(e) cusdta
C if %error = '1'
C callp Print('Open of CUSDTA file failed')
C close cuspi
C return error
C endif
* Read each record of CUSDTA
C read(e) cusdtarec
C dow %eof <> '1'
* If accounts receivable balance > 0, decrypt customer data and
* create a bill
C if CARBAL > 0
* Decrypt customer information
C eval QC3IV = CIV
C eval plainLen = %size(CCUSDTA)
C eval cipherLen = %size(ECUSDTA)
C callp DecryptData( CCUSDTA :cipherLen
C :QC3D0200 :'ALGD0200'
C :FKctx :'KEYD0100'
C :csp :*OMIT
C :ECUSDTA :plainLen
C :rtnLen :QUSEC)
C callp Create_Bill( ECUSDTA :CARBAL)
C endif
C read(e) cusdtarec
C enddo
* Cleanup
C eval ecusdta = *loval
C callp DestroyKeyCtx( FKctx :QUSEC)
C callp DestroyKeyCtx( KEKctx :QUSEC)
C callp DestroyAlgCtx( AESctx :QUSEC)
C close cusdta
C return ok
P e
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