Description
ASCON was recently selected as the best of the 57 proposals submitted to NIST Lightweight Cryptography competition. The whole program lasted for four years, having started in 2019. ASCON is a family of functions for Authenticated encryption (AEAD) and hashing (fixed or variable output length).
Usage
For online hashing (input source is read/received in chunks) use CryptoAsconHashInit, CryptoAsconHashUpdate and CryptoAsconHashFinalize procedures and for offline (in-memory) operations can use the more convenient helpers CryptoAsconHashByteArray and CryptoAsconHashText procedures.
For authenticated encryption/verified decryption use offline CryptoAsconEncrypt and CryptoAsconDecrypt which operate in-place on the input buffer and return/expect the authentication tag detached in a separate byte-array.
Source
mdAscon.bas
cheers,
</wqw>
ASCON was recently selected as the best of the 57 proposals submitted to NIST Lightweight Cryptography competition. The whole program lasted for four years, having started in 2019. ASCON is a family of functions for Authenticated encryption (AEAD) and hashing (fixed or variable output length).
Usage
For online hashing (input source is read/received in chunks) use CryptoAsconHashInit, CryptoAsconHashUpdate and CryptoAsconHashFinalize procedures and for offline (in-memory) operations can use the more convenient helpers CryptoAsconHashByteArray and CryptoAsconHashText procedures.
For authenticated encryption/verified decryption use offline CryptoAsconEncrypt and CryptoAsconDecrypt which operate in-place on the input buffer and return/expect the authentication tag detached in a separate byte-array.
Source
mdAscon.bas
Code:
'--- mdAscon.bas
Option Explicit
DefObj A-Z
#Const HasPtrSafe = (VBA7 <> 0)
#Const HasOperators = (TWINBASIC <> 0)
#If HasPtrSafe Then
Private Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As LongPtr)
Private Declare PtrSafe Function ArrPtr Lib "vbe7" Alias "VarPtr" (Ptr() As Any) As LongPtr
Private Declare PtrSafe Function VariantChangeType Lib "oleaut32" (Dest As Variant, Src As Variant, ByVal wFlags As Integer, ByVal vt As VbVarType) As Long
Private Declare PtrSafe Function WideCharToMultiByte Lib "kernel32" (ByVal CodePage As Long, ByVal dwFlags As Long, ByVal lpWideCharStr As LongPtr, ByVal cchWideChar As Long, lpMultiByteStr As Any, ByVal cchMultiByte As Long, ByVal lpDefaultChar As Long, ByVal lpUsedDefaultChar As Long) As Long
#Else
Private Enum LongPtr
[_]
End Enum
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As LongPtr)
Private Declare Function ArrPtr Lib "msvbvm60" Alias "VarPtr" (Ptr() As Any) As LongPtr
Private Declare Function VariantChangeType Lib "oleaut32" (Dest As Variant, Src As Variant, ByVal wFlags As Integer, ByVal vt As VbVarType) As Long
Private Declare Function WideCharToMultiByte Lib "kernel32" (ByVal CodePage As Long, ByVal dwFlags As Long, ByVal lpWideCharStr As LongPtr, ByVal cchWideChar As Long, lpMultiByteStr As Any, ByVal cchMultiByte As Long, ByVal lpDefaultChar As Long, ByVal lpUsedDefaultChar As Long) As Long
#End If
Private Const LNG_KEYSZ As Long = 16
Private Const LNG_LONGKEYSZ As Long = 20
Private Const LNG_NONCESZ As Long = 16
Private Const LNG_TAGSZ As Long = 16
Private Const LNG_ROUNDS As Long = 12
Private Const LNG_STATESZ As Long = 40
Private Type SAFEARRAY1D
cDims As Integer
fFeatures As Integer
cbElements As Long
cLocks As Long
pvData As LongPtr
cElements As Long
lLbound As Long
End Type
Public Type CryptoAsconContext
Words(0 To LNG_STATESZ \ 8 - 1) As Currency
Absorbed As Long
RoundsItermediate As Long
RoundsFinal As Long
Rate As Long
Bytes() As Byte
PeekArray As SAFEARRAY1D
End Type
#If Not HasOperators Then
#If HasPtrSafe Then
Private LNG_POW2(0 To 63) As LongLong
Private LNG_SIGN_BIT As LongLong ' 2 ^ 63
#Else
Private LNG_POW2(0 To 63) As Variant
Private LNG_SIGN_BIT As Variant
#End If
#If HasPtrSafe Then
Private Function RotR64(ByVal lX As LongLong, ByVal lN As Long) As LongLong
#Else
Private Function RotR64(lX As Variant, ByVal lN As Long) As Variant
#End If
'--- RotR64 = RShift64(X, n) Or LShift64(X, 64 - n)
Debug.Assert lN <> 0
RotR64 = ((lX And (-1 Xor LNG_SIGN_BIT)) \ LNG_POW2(lN) Or -(lX < 0) * LNG_POW2(63 - lN)) Or _
((lX And (LNG_POW2(lN - 1) - 1)) * LNG_POW2(64 - lN) Or -((lX And LNG_POW2(lN - 1)) <> 0) * LNG_SIGN_BIT)
End Function
#If Not HasPtrSafe Then
Private Function CLngLng(vValue As Variant) As Variant
Const VT_I8 As Long = &H14
Call VariantChangeType(CLngLng, vValue, 0, VT_I8)
End Function
Private Function ToLngLng(ByVal cValue As Currency) As Variant
Const VT_I8 As Long = &H14
Static B(0 To 1) As Long
Dim lIdx As Long
Call CopyMemory(B(0), cValue, 8)
lIdx = B(0)
B(0) = BSwap32(B(1))
B(1) = BSwap32(lIdx)
Call VariantChangeType(ToLngLng, ToLngLng, 0, VT_I8)
#If LargeAddressAware Then
Call CopyMemory(ByVal (VarPtr(ToLngLng) Xor &H80000000) + 8 Xor &H80000000, B(0), 8)
#Else
Call CopyMemory(ByVal VarPtr(ToLngLng) + 8, B(0), 8)
#End If
End Function
Private Function FromLngLng(lValue As Variant) As Currency
Static B(0 To 1) As Long
Dim lIdx As Long
#If LargeAddressAware Then
Call CopyMemory(B(0), ByVal (VarPtr(lValue) Xor &H80000000) + 8 Xor &H80000000, 8)
#Else
Call CopyMemory(B(0), ByVal VarPtr(lValue) + 8, 8)
#End If
lIdx = B(0)
B(0) = BSwap32(B(1))
B(1) = BSwap32(lIdx)
Call CopyMemory(FromLngLng, B(0), 8)
End Function
#Else
Private Function ToLngLng(ByVal cValue As Currency) As LongLong
Const VT_I8 As Long = &H14
Static B(0 To 1) As Long
Dim lIdx As Long
Call CopyMemory(B(0), cValue, 8)
lIdx = B(0)
B(0) = BSwap32(B(1))
B(1) = BSwap32(lIdx)
Call CopyMemory(ToLngLng, B(0), 8)
End Function
Private Function FromLngLng(ByVal lValue As LongLong) As Currency
Static B(0 To 1) As Long
Dim lIdx As Long
Call CopyMemory(B(0), lValue, 8)
lIdx = B(0)
B(0) = BSwap32(B(1))
B(1) = BSwap32(lIdx)
Call CopyMemory(FromLngLng, B(0), 8)
End Function
#End If
Private Function BSwap32(ByVal lX As Long) As Long
BSwap32 = (lX And &H7F) * &H1000000 Or (lX And &HFF00&) * &H100 Or (lX And &HFF0000) \ &H100 Or _
(lX And &HFF000000) \ &H1000000 And &HFF Or -((lX And &H80) <> 0) * &H80000000
End Function
Private Sub pvPermute(uCtx As CryptoAsconContext, ByVal lRounds As Long)
#If HasPtrSafe Then
Dim S0 As LongLong
Dim S1 As LongLong
Dim S2 As LongLong
Dim S3 As LongLong
Dim S4 As LongLong
Dim lTemp As LongLong
#Else
Dim S0 As Variant
Dim S1 As Variant
Dim S2 As Variant
Dim S3 As Variant
Dim S4 As Variant
Dim lTemp As Variant
#End If
Dim lIdx As Long
With uCtx
S0 = ToLngLng(.Words(0))
S1 = ToLngLng(.Words(1))
S2 = ToLngLng(.Words(2))
S3 = ToLngLng(.Words(3))
S4 = ToLngLng(.Words(4))
For lIdx = LNG_ROUNDS - lRounds To LNG_ROUNDS - 1
'--- round constant
S2 = S2 Xor (&HF0 - lIdx * 15)
'--- s-box layer
S0 = S0 Xor S4
S4 = S4 Xor S3
S2 = S2 Xor S1
lTemp = S0 And Not S4
S0 = S0 Xor (S2 And Not S1)
S2 = S2 Xor (S4 And Not S3)
S4 = S4 Xor (S1 And Not S0)
S1 = S1 Xor (S3 And Not S2)
S3 = S3 Xor lTemp
S1 = S1 Xor S0
S0 = S0 Xor S4
S3 = S3 Xor S2
S2 = Not S2
'--- linear layer
S0 = S0 Xor RotR64(S0, 19) Xor RotR64(S0, 28)
S1 = S1 Xor RotR64(S1, 61) Xor RotR64(S1, 39)
S2 = S2 Xor RotR64(S2, 1) Xor RotR64(S2, 6)
S3 = S3 Xor RotR64(S3, 10) Xor RotR64(S3, 17)
S4 = S4 Xor RotR64(S4, 7) Xor RotR64(S4, 41)
#If DebugPermutation Then
.Words(0) = FromLngLng(S0)
.Words(1) = FromLngLng(S1)
.Words(2) = FromLngLng(S2)
.Words(3) = FromLngLng(S3)
.Words(4) = FromLngLng(S4)
Debug.Print ToHex(uCtx.Bytes)
#End If
Next
.Words(0) = FromLngLng(S0)
.Words(1) = FromLngLng(S1)
.Words(2) = FromLngLng(S2)
.Words(3) = FromLngLng(S3)
.Words(4) = FromLngLng(S4)
End With
End Sub
#Else
Private Type ArrayLongLong5
Item(0 To 4) As LongLong
End Type
Private Function BSwap32(ByVal lX As Long) As Long
lX = ((lX << 8) And &HFF00FF00) Or ((lX >> 8) And &HFF00FF)
Return (lX << 16) Or (lX >> 16)
End Function
Private Sub pvAssign(uArray As ArrayLongLong5, S0 As LongLong, S1 As LongLong, S2 As LongLong, S3 As LongLong, S4 As LongLong)
With uArray
S0 = .Item(0)
S1 = .Item(1)
S2 = .Item(2)
S3 = .Item(3)
S4 = .Item(4)
End With
End Sub
Private Sub pvUnassign(uArray As ArrayLongLong5, S0 As LongLong, S1 As LongLong, S2 As LongLong, S3 As LongLong, S4 As LongLong)
With uArray
.Item(0) = S0
.Item(1) = S1
.Item(2) = S2
.Item(3) = S3
.Item(4) = S4
End With
End Sub
'[ IntegerOverflowChecks (False) ]
Private Sub pvPermute(uCtx As CryptoAsconContext, ByVal lRounds As Long)
Static B(0 To 9) As Long
Static C(0 To 9) As Long
Dim S0 As LongLong
Dim S1 As LongLong
Dim S2 As LongLong
Dim S3 As LongLong
Dim S4 As LongLong
Dim lTemp As LongLong
Dim lIdx As Long
With uCtx
Call CopyMemory(B(0), .Bytes(0), LNG_STATESZ)
C(0) = BSwap32(B(1))
C(1) = BSwap32(B(0))
C(2) = BSwap32(B(3))
C(3) = BSwap32(B(2))
C(4) = BSwap32(B(5))
C(5) = BSwap32(B(4))
C(6) = BSwap32(B(7))
C(7) = BSwap32(B(6))
C(8) = BSwap32(B(9))
C(9) = BSwap32(B(8))
pvAssign VarPtr(C(0)), S0, S1, S2, S3, S4
For lIdx = LNG_ROUNDS - lRounds To LNG_ROUNDS - 1
'--- round constant
S2 = S2 Xor (&HF0 - lIdx * 15)
'--- s-box layer
S0 = S0 Xor S4
S4 = S4 Xor S3
S2 = S2 Xor S1
lTemp = S0 And Not S4
S0 = S0 Xor (S2 And Not S1)
S2 = S2 Xor (S4 And Not S3)
S4 = S4 Xor (S1 And Not S0)
S1 = S1 Xor (S3 And Not S2)
S3 = S3 Xor lTemp
S1 = S1 Xor S0
S0 = S0 Xor S4
S3 = S3 Xor S2
S2 = Not S2
'--- linear layer
lTemp = S0 Xor (S0 >> 9 Or S0 << 55)
S0 = S0 Xor (lTemp >> 19 Or lTemp << 45)
lTemp = S1 Xor (S1 >> 22 Or S1 << 42)
S1 = S1 Xor (lTemp >> 39 Or lTemp << 25)
lTemp = S2 Xor (S2 >> 5 Or S2 << 59)
S2 = S2 Xor (lTemp >> 1 Or lTemp << 63)
lTemp = S3 Xor (S3 >> 7 Or S3 << 57)
S3 = S3 Xor (lTemp >> 10 Or lTemp << 54)
lTemp = S4 Xor (S4 >> 34 Or S4 << 30)
S4 = S4 Xor (lTemp >> 7 Or lTemp << 57)
Next
pvUnassign VarPtr(C(0)), S0, S1, S2, S3, S4
B(0) = BSwap32(C(1))
B(1) = BSwap32(C(0))
B(2) = BSwap32(C(3))
B(3) = BSwap32(C(2))
B(4) = BSwap32(C(5))
B(5) = BSwap32(C(4))
B(6) = BSwap32(C(7))
B(7) = BSwap32(C(6))
B(8) = BSwap32(C(9))
B(9) = BSwap32(C(8))
Call CopyMemory(.Bytes(0), B(0), LNG_STATESZ)
End With
End Sub
#End If
Private Sub pvInit(uCtx As CryptoAsconContext)
Const FADF_AUTO As Long = 1
Dim lIdx As Long
#If Not HasOperators Then
If LNG_POW2(0) = 0 Then
LNG_POW2(0) = CLngLng(1)
For lIdx = 1 To 63
LNG_POW2(lIdx) = CVar(LNG_POW2(lIdx - 1)) * 2
Next
LNG_SIGN_BIT = LNG_POW2(63)
End If
#End If
With uCtx
If .PeekArray.cDims = 0 Then
With .PeekArray
.cDims = 1
.fFeatures = FADF_AUTO
.cbElements = 1
.cLocks = 1
.pvData = VarPtr(uCtx.Words(0))
.cElements = LNG_STATESZ
End With
Dim pDummy As LongPtr
Call CopyMemory(ByVal ArrPtr(.Bytes), VarPtr(.PeekArray), LenB(pDummy))
End If
End With
End Sub
Private Sub pvInitHash(uCtx As CryptoAsconContext, Optional AsconVariant As String)
Dim sState As Variant
Dim vElem As Variant
Dim lIdx As Long
pvInit uCtx
With uCtx
.Absorbed = 0
Select Case LCase$(AsconVariant)
Case "ascon-hash", vbNullString
.RoundsItermediate = LNG_ROUNDS
sState = "446318142388178.635 14863613160486.9771 712324061313542.0084 -166521396747559.9293 467505948832861.778"
Case "ascon-hasha"
.RoundsItermediate = 8
sState = "-647381232885581.2351 -634115870784097.1149 549226995250965.9182 902277108517712.4566 -867907184661769.5071"
Case "ascon-xof"
.RoundsItermediate = LNG_ROUNDS
sState = "164502388182400.9909 231616784492634.5515 173919820479251.3382 89321191666631.817 -529072205218721.0161"
Case "ascon-xofa"
.RoundsItermediate = 8
sState = "364579992601713.466 362688130062775.4445 296372296757763.8391 656682645757712.1828 458221163737440.5544"
Case Else
Err.Raise vbObjectError, , "Invalid variant for Ascon hash (" & AsconVariant & ")"
End Select
.Rate = 8
.RoundsFinal = LNG_ROUNDS
'--- init state
lIdx = 0
For Each vElem In Split(sState)
.Words(lIdx) = vElem
lIdx = lIdx + 1
Next
End With
End Sub
Private Sub pvInitAead(uCtx As CryptoAsconContext, baKey() As Byte, Nonce As Variant, AssociatedData As Variant, AsconVariant As String)
Dim baNonce() As Byte
Dim baAad() As Byte
Dim lIdx As Long
Dim lSize As Long
pvInit uCtx
If IsMissing(Nonce) Then
baNonce = vbNullString
Else
baNonce = Nonce
End If
ReDim Preserve baNonce(0 To LNG_NONCESZ - 1) As Byte
If IsMissing(AssociatedData) Then
baAad = vbNullString
Else
baAad = AssociatedData
End If
With uCtx
.Absorbed = 0
Select Case LCase$(AsconVariant)
Case "ascon-128", vbNullString
.RoundsItermediate = LNG_ROUNDS \ 2
.Rate = 8
.Words(0) = 10146.624@
Debug.Assert UBound(baKey) + 1 = LNG_KEYSZ
ReDim Preserve baKey(0 To LNG_KEYSZ - 1) As Byte
Case "ascon-128a"
.RoundsItermediate = 8
.Rate = 16
.Words(0) = 13503.7056@
Debug.Assert UBound(baKey) + 1 = LNG_KEYSZ
ReDim Preserve baKey(0 To LNG_KEYSZ - 1) As Byte
Case "ascon-80pq"
.RoundsItermediate = LNG_ROUNDS \ 2
.Rate = 8
.Words(0) = 10146.6272@
Debug.Assert UBound(baKey) + 1 = LNG_LONGKEYSZ
ReDim Preserve baKey(0 To LNG_LONGKEYSZ - 1) As Byte
Case Else
Err.Raise vbObjectError, , "Invalid variant for Ascon AEAD (" & AsconVariant & ")"
End Select
.RoundsFinal = LNG_ROUNDS
'--- init state
For lIdx = 1 To UBound(.Words)
.Words(lIdx) = 0
Next
lSize = UBound(baKey) + 1
Call CopyMemory(.Bytes(LNG_STATESZ - LNG_NONCESZ - lSize), baKey(0), lSize)
Call CopyMemory(.Bytes(LNG_STATESZ - LNG_NONCESZ), baNonce(0), LNG_NONCESZ)
pvPermute uCtx, .RoundsFinal
lSize = LNG_STATESZ - UBound(baKey) - 1
For lIdx = 0 To UBound(baKey)
.Bytes(lSize + lIdx) = .Bytes(lSize + lIdx) Xor baKey(lIdx)
Next
'--- process associated data
If UBound(baAad) >= 0 Then
pvUpdate uCtx, baAad, 0, UBound(baAad) + 1
.Bytes(.Absorbed) = .Bytes(.Absorbed) Xor &H80
pvPermute uCtx, .RoundsItermediate
.Absorbed = 0
End If
'--- separator
.Bytes(LNG_STATESZ - 1) = .Bytes(LNG_STATESZ - 1) Xor 1
End With
End Sub
Private Sub pvUpdate(uCtx As CryptoAsconContext, baInput() As Byte, ByVal Pos As Long, ByVal Size As Long, Optional ByVal Encrypt As Boolean, Optional ByVal Decrypt As Boolean)
Dim lIdx As Long
Dim lTemp As Long
If Size < 0 Then
Size = UBound(baInput) + 1 - Pos
End If
With uCtx
For lIdx = 0 To Size - 1
If Decrypt Then
lTemp = .Bytes(.Absorbed) Xor baInput(Pos + lIdx)
.Bytes(.Absorbed) = baInput(Pos + lIdx)
baInput(Pos + lIdx) = lTemp
Else
.Bytes(.Absorbed) = .Bytes(.Absorbed) Xor baInput(Pos + lIdx)
End If
If .Absorbed = .Rate - 1 Then
pvPermute uCtx, .RoundsItermediate
If Encrypt Then
Call CopyMemory(baInput(Pos + lIdx - .Absorbed), .Bytes(0), .Rate)
End If
.Absorbed = 0
Else
.Absorbed = .Absorbed + 1
End If
Next
If Encrypt Then
If .Absorbed > 0 Then
Call CopyMemory(baInput(Pos + lIdx - .Absorbed), .Bytes(0), .Absorbed)
End If
End If
End With
End Sub
Private Sub pvFinalize(uCtx As CryptoAsconContext, baKey() As Byte, baTag() As Byte)
Dim lIdx As Long
Dim lSize As Long
With uCtx
.Bytes(.Absorbed) = .Bytes(.Absorbed) Xor &H80
lSize = .Rate
For lIdx = 0 To UBound(baKey)
.Bytes(lSize + lIdx) = .Bytes(lSize + lIdx) Xor baKey(lIdx)
Next
pvPermute uCtx, .RoundsFinal
lSize = LNG_STATESZ - UBound(baKey) - 1
For lIdx = 0 To UBound(baKey)
.Bytes(lSize + lIdx) = .Bytes(lSize + lIdx) Xor baKey(lIdx)
Next
ReDim baTag(0 To LNG_TAGSZ - 1) As Byte
Call CopyMemory(baTag(0), .Bytes(LNG_STATESZ - LNG_TAGSZ), LNG_TAGSZ)
End With
End Sub
Public Sub CryptoAsconHashInit(uCtx As CryptoAsconContext, Optional AsconVariant As String)
pvInitHash uCtx, AsconVariant
End Sub
Public Sub CryptoAsconHashUpdate(uCtx As CryptoAsconContext, baInput() As Byte, Optional ByVal Pos As Long, Optional ByVal Size As Long = -1)
pvUpdate uCtx, baInput, Pos, Size
End Sub
Public Sub CryptoAsconHashFinalize(uCtx As CryptoAsconContext, baOutput() As Byte, Optional ByVal OutSize As Long)
Dim lIdx As Long
Dim uEmpty As CryptoAsconContext
With uCtx
.Bytes(.Absorbed) = .Bytes(.Absorbed) Xor &H80
pvPermute uCtx, .RoundsFinal
.Absorbed = 0
If OutSize = 0 Then
OutSize = 32
End If
ReDim baOutput(0 To OutSize - 1) As Byte
For lIdx = 0 To UBound(baOutput)
baOutput(lIdx) = .Bytes(.Absorbed)
If .Absorbed = .Rate - 1 Then
pvPermute uCtx, .RoundsItermediate
.Absorbed = 0
Else
.Absorbed = .Absorbed + 1
End If
Next
Dim pDummy As LongPtr
Call CopyMemory(ByVal ArrPtr(.Bytes), pDummy, LenB(pDummy))
End With
uCtx = uEmpty
End Sub
Public Function CryptoAsconHashByteArray(baInput() As Byte, Optional ByVal Pos As Long, Optional ByVal Size As Long = -1, Optional AsconVariant As String) As Byte()
Dim uCtx As CryptoAsconContext
CryptoAsconHashInit uCtx, AsconVariant
CryptoAsconHashUpdate uCtx, baInput, Pos, Size
CryptoAsconHashFinalize uCtx, CryptoAsconHashByteArray
End Function
Private Function ToUtf8Array(sText As String) As Byte()
Const CP_UTF8 As Long = 65001
Dim baRetVal() As Byte
Dim lSize As Long
ReDim baRetVal(0 To 4 * Len(sText)) As Byte
lSize = WideCharToMultiByte(CP_UTF8, 0, StrPtr(sText), Len(sText), baRetVal(0), UBound(baRetVal) + 1, 0, 0)
If lSize > 0 Then
ReDim Preserve baRetVal(0 To lSize - 1) As Byte
Else
baRetVal = vbNullString
End If
ToUtf8Array = baRetVal
End Function
Private Function ToHex(baData() As Byte) As String
Dim lIdx As Long
Dim sByte As String
ToHex = String$(UBound(baData) * 2 + 2, 48)
For lIdx = 0 To UBound(baData)
sByte = LCase$(Hex$(baData(lIdx)))
Mid$(ToHex, lIdx * 2 + 3 - Len(sByte)) = sByte
Next
End Function
Public Function CryptoAsconHashText(sText As String, Optional AsconVariant As String) As String
CryptoAsconHashText = ToHex(CryptoAsconHashByteArray(ToUtf8Array(sText), AsconVariant:=AsconVariant))
End Function
Public Sub CryptoAsconEncrypt(baKey() As Byte, baTag() As Byte, _
baInput() As Byte, Optional ByVal Pos As Long, Optional ByVal Size As Long = -1, _
Optional Nonce As Variant, Optional AssociatedData As Variant, Optional AsconVariant As String)
Dim uCtx As CryptoAsconContext
pvInitAead uCtx, baKey, Nonce, AssociatedData, AsconVariant
pvUpdate uCtx, baInput, Pos, Size, Encrypt:=True
pvFinalize uCtx, baKey, baTag
End Sub
Public Function CryptoAsconDecrypt(baKey() As Byte, baTag() As Byte, _
baInput() As Byte, Optional ByVal Pos As Long, Optional ByVal Size As Long = -1, _
Optional Nonce As Variant, Optional AssociatedData As Variant, Optional AsconVariant As String) As Boolean
Dim uCtx As CryptoAsconContext
Dim baTemp() As Byte
pvInitAead uCtx, baKey, Nonce, AssociatedData, AsconVariant
pvUpdate uCtx, baInput, Pos, Size, Decrypt:=True
pvFinalize uCtx, baKey, baTemp
If UBound(baTemp) = UBound(baTag) Then
CryptoAsconDecrypt = (InStrB(baTemp, baTag) = 1)
End If
End Function</wqw>