VistA-FOIAVistA/r/IFCAP-PRC-PRX--PRCA--PRCN/PRCHES11.m

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Mathematica

PRCHES11 ;WISC/RHD/AKS-ESIG MAINTENANCE ROUTINE ; 1/4/93 11:04 AM
V ;;5.1;IFCAP;;Oct 20, 2000
;Per VHA Directive 10-93-142, this routine should not be modified.
;ROUTINE FOR MAINTAINING FIELD 3 (ELECTRONIC SIGNATURE), FILE 443
DECODE(LEVEL0) ;Extrinsic Function to return hashed esig to readable form.
;returns "" if unsuccessful
NEW RECORD,RECORD1,RECORD12,VERSION,PERSON,SIG,CHECKSUM
S RECORD=$G(^PRC(443,LEVEL0,0)) I RECORD="" Q ""
S VERSION=$P(RECORD,"^",14)
S PERSON=+$P(RECORD,"^",2)
I VERSION'="",VERSION'=1 Q ""
S SIG=$P(RECORD,"^",3)
D1 ;decode e signature for version 1
S CHECKSUM=$$SUM^PRCUESIG(LEVEL0_"^"_$$STRING(RECORD))
Q $$DECODE^PRCUESIG(SIG,PERSON,CHECKSUM)
ENCODE(LEVEL0,USERNUM,Y) ;Encode esig for version 1 only
NEW RECORD,SIGBLOCK,CHECKSUM,OLDUSER
S USERNUM=+USERNUM
I USERNUM=0 S Y=-3 Q ;-3 no user number
S SIGBLOCK=$P($G(^VA(200,USERNUM,20)),"^",2)
I SIGBLOCK="" S Y=-2 Q ;-2 no signature block
S RECORD=$G(^PRC(443,LEVEL0,0))
I RECORD="" S Y=-1 Q ;-1 no record
I $P(RECORD,"^",3)'="" S Y=-4 Q ;-4 cannot re-sign record
S OLDUSER=+$P(RECORD,"^",2)
I OLDUSER=0 S $P(RECORD,"^",2)=USERNUM
I OLDUSER>0 S USERNUM=OLDUSER
S:$P(RECORD,"^",4)="" $P(RECORD,"^",4)=$$NOW^PRCUESIG
S CHECKSUM=$$SUM^PRCUESIG(LEVEL0_"^"_$$STRING(RECORD))
S $P(RECORD,"^",3)=$$ENCODE^PRCUESIG(SIGBLOCK,USERNUM,CHECKSUM)
S $P(RECORD,"^",14)=1,$P(RECORD,"^",13)=$$SUM^PRCUESIG(SIGBLOCK)
S ^PRC(443,LEVEL0,0)=RECORD
S Y=1 Q
REMOVE(LEVEL0) ;Entry point to remove esig
NEW I,RECORD
S RECORD=$G(^PRC(443,LEVEL0,0))
F I=2,3,4,13 S $P(RECORD,"^",I)=""
S ^PRC(443,LEVEL0,0)=RECORD
Q
VERIFY(LEVEL0) ;extrinsic function to verify version 1 signature. Returns 1 if valid, 0 if not valid
NEW RECORD,VERSION,SIGBLOCK
S RECORD=$G(^PRC(443,LEVEL0,0))
S VERSION=$P(RECORD,"^",14),SIGBLOCK=$P(RECORD,"^",13)
I VERSION_SIGBLOCK="" Q 1
Q ($$SUM^PRCUESIG($$DECODE(LEVEL0))=SIGBLOCK)
STRING(X) ;Build String of critical fields
Q $P(X,"^")_"^"_$P(X,"^",4)_"^"_$P(X,"^",9)