| 1 | PRCHES11 ;WISC/RHD/AKS-ESIG MAINTENANCE ROUTINE ; 1/4/93  11:04 AM
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| 2 | V ;;5.1;IFCAP;;Oct 20, 2000
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| 3 |  ;Per VHA Directive 10-93-142, this routine should not be modified.
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| 4 |  ;ROUTINE FOR MAINTAINING FIELD 3 (ELECTRONIC SIGNATURE), FILE 443
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| 5 | DECODE(LEVEL0) ;Extrinsic Function to return hashed esig to readable form.
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| 6 |  ;returns "" if unsuccessful
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| 7 |  NEW RECORD,RECORD1,RECORD12,VERSION,PERSON,SIG,CHECKSUM
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| 8 |  S RECORD=$G(^PRC(443,LEVEL0,0)) I RECORD="" Q ""
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| 9 |  S VERSION=$P(RECORD,"^",14)
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| 10 |  S PERSON=+$P(RECORD,"^",2)
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| 11 |  I VERSION'="",VERSION'=1 Q ""
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| 12 |  S SIG=$P(RECORD,"^",3)
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| 13 | D1 ;decode e signature for version 1
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| 14 |  S CHECKSUM=$$SUM^PRCUESIG(LEVEL0_"^"_$$STRING(RECORD))
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| 15 |  Q $$DECODE^PRCUESIG(SIG,PERSON,CHECKSUM)
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| 16 | ENCODE(LEVEL0,USERNUM,Y) ;Encode esig for version 1 only
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| 17 |  NEW RECORD,SIGBLOCK,CHECKSUM,OLDUSER
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| 18 |  S USERNUM=+USERNUM
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| 19 |  I USERNUM=0 S Y=-3 Q  ;-3 no user number
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| 20 |  S SIGBLOCK=$P($G(^VA(200,USERNUM,20)),"^",2)
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| 21 |  I SIGBLOCK="" S Y=-2 Q  ;-2 no signature block
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| 22 |  S RECORD=$G(^PRC(443,LEVEL0,0))
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| 23 |  I RECORD="" S Y=-1 Q  ;-1 no record
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| 24 |  I $P(RECORD,"^",3)'="" S Y=-4 Q  ;-4 cannot re-sign record
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| 25 |  S OLDUSER=+$P(RECORD,"^",2)
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| 26 |  I OLDUSER=0 S $P(RECORD,"^",2)=USERNUM
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| 27 |  I OLDUSER>0 S USERNUM=OLDUSER
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| 28 |  S:$P(RECORD,"^",4)="" $P(RECORD,"^",4)=$$NOW^PRCUESIG
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| 29 |  S CHECKSUM=$$SUM^PRCUESIG(LEVEL0_"^"_$$STRING(RECORD))
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| 30 |  S $P(RECORD,"^",3)=$$ENCODE^PRCUESIG(SIGBLOCK,USERNUM,CHECKSUM)
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| 31 |  S $P(RECORD,"^",14)=1,$P(RECORD,"^",13)=$$SUM^PRCUESIG(SIGBLOCK)
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| 32 |  S ^PRC(443,LEVEL0,0)=RECORD
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| 33 |  S Y=1 Q
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| 34 | REMOVE(LEVEL0) ;Entry point to remove esig
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| 35 |  NEW I,RECORD
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| 36 |  S RECORD=$G(^PRC(443,LEVEL0,0))
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| 37 |  F I=2,3,4,13 S $P(RECORD,"^",I)=""
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| 38 |  S ^PRC(443,LEVEL0,0)=RECORD
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| 39 |  Q
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| 40 | VERIFY(LEVEL0)      ;extrinsic function to verify version 1 signature.  Returns 1 if valid, 0 if not valid
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| 41 |  NEW RECORD,VERSION,SIGBLOCK
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| 42 |  S RECORD=$G(^PRC(443,LEVEL0,0))
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| 43 |  S VERSION=$P(RECORD,"^",14),SIGBLOCK=$P(RECORD,"^",13)
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| 44 |  I VERSION_SIGBLOCK="" Q 1
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| 45 |  Q ($$SUM^PRCUESIG($$DECODE(LEVEL0))=SIGBLOCK)
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| 46 | STRING(X)          ;Build String of critical fields
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| 47 |  Q $P(X,"^")_"^"_$P(X,"^",4)_"^"_$P(X,"^",9)
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