Xojo Plugin

Example: Hash Text in Chunks

Shows how to generate a final hash, like SHA-256, for a large text by processing it in chunks. Xojo Plugin

Dim success As Boolean
success = False

Dim crypt As New Chilkat.Crypt2
crypt.HashAlgorithm = "sha256"
crypt.Charset = "utf-8"

Dim bd As New Chilkat.BinData

Dim s As String
s = "The quick brown fox jumped over the lazy dog." + EndOfLine.Windows

// Accumulate the text in a StringBuilder.  We'll demonstrate hashing the text in chunks,
// and then also hashing the entire text at once to show the results are the same.

success = bd.AppendString(s,"utf-8")
success = crypt.HashBeginString(s)

Dim i As Int32
i = 0
While i < 200
    success = bd.AppendString(s,"utf-8")
    success = crypt.HashMoreString(s)
    i = i + 1
Wend

// Get the hash in base64 format.
crypt.EncodingMode = "base64"

Dim encodedHash As String
encodedHash = crypt.HashFinalENC()
System.DebugLog("Hash computed in chunks: " + encodedHash)

// Let's alternatively compute the hash of the entire amount of data at once,
// to show the hash computation is the same:
encodedHash = crypt.HashBdENC(bd)
System.DebugLog("Hash computed in 1 step: " + encodedHash)

// Output:

// Hash computed in chunks: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
// Hash computed in 1 step: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=