Problem:
The SHA1 is a standard hashing algorithm that given a sting of bytes will produce a hash code for the string. Any changes to the string would result in a very different hash code so it can be used to ensure a message has not been tampered with.
How you use this algorithm in .Net COBOL ?
Resolution:
The .Net Framework contains an implementation the SHA1 algorithm. You can use these classes from COBOL.
An example project that does this is attached to this RPI.
The program code is:-
$set sourceformat"variable"
program-id. HashIt as "SHA1Hash.Hashit".
environment division.
configuration section.
repository.
class cSHA1Managed as "System.Security.Cryptography.SHA1Managed"
class cStringBuilder as "System.Text.StringBuilder"
.
data division.
working-storage section.
01 mymessage pic x(22) value "This is a TEST String.".
01 mySHA1 cSHA1Managed.
01 myByteArray binary-char unsigned occurs any. *> Byte Array
01 myHash binary-char unsigned occurs any. *> Byte Array
01 ws-byte binary-char unsigned. *> Byte
01 strBuilder cStringBuilder.
01 array-len binary-long.
procedure division.
***** Create a SHA1 Hashing Instance
set mySHA1 to cSHA1Managed::"New"()
set myByteArray to mymessage
set myHash to mySHA1::"ComputeHash"(myByteArray)
***** Now output a hex representation of the SHA1 Hash
perform create-hex-string
display "Message=" mymessage
display "SHA1 Hash Code=" strBuilder
goback.
create-hex-string section.
******************************************
* Create Hex String from Byte[]
******************************************
set strBuilder to cStringBuilder::"New"()
set array-len to myHash::"Length"
move length of myHash to array-len
perform varying ws-byte through myHash
invoke strBuilder::"Append"(String::"Format"("{0,2:x}", ws-byte)::"Replace"(" " , "0"))
end-perform
.
end program HashIt.
