saving and reading encrypted crypto files

hlo

Member
Licensed User
working on a medical database and needing to encrypt some data in it. used crypto but found I had trouble figuring out how to save a retrieve encrypted data. here is what i came up with. may not be the best way, but it works.

'Crypto is a Crypto object, Bit is a Bitwise object, Bin is a Binaryfile object
Sub Globals
Dim string(0) As Byte, secret(0) As Byte, s3(0) As Byte,string2(0) As Byte
s4=""
x=0
length=0
'used lots of variables so no chance of cross over of data for demo
PassPhrase = "password" 'not recomended - best to save password as an encrypted file to compare with what is typed in
txtString="begin- a text file to encrypt -end" 'just a file to encrypt than decrypt
End Sub

Sub App_Start
FileClose(c2) 'i always close my files 1st to be sure
FileClose(c1)
Bit.New1
Crypto.New1
encryptx 'encrypt and save routine
decryptx 're-read then decrypt routine
AppClose
End Sub

Sub Encryptx
string() = Bit.StringToBytes(txtString,0,StrLength(txtString)) 'convert the string to bytes
secret() = Crypto.Encrypt(PassPhrase, string()) 'crypto routine
x=ArrayLen(secret()) 'get length of array to save
FileOpen(c1,"test.txt",cRandom)
bin.New1(c1,True)
bin.WriteInt16(x) 'save length of array
bin.WriteBytes(secret()) 'save encrypted data as bytes
FileClose(c1)
Msgbox("done encrypt")
End Sub

Sub decryptx
FileOpen(c2,"test.txt",cRandom)
bin.New1(c2,True)
x2=bin.ReadInt16 'read in array size
Dim s3(x2) As byte 'reset dim to proper size - believe it or not, this makes a difference
length = bin.ReadBytes(s3(), x2) 'read in string for x2 bytes - length variable not used
FileClose(c2)
string2()=crypto.Decrypt(PassPhrase,s3()) 'crypto routine
txtString=bit.BytesToString(string(),0,ArrayLen(string2())) 'turn back to string
Msgbox("decrypted file "&txtstring)
End Sub

hope it helps some one.
 

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