Option Explicit
Private Const C_SHA256 As Long = 1
Private Const C_SHA384 As Long = 2
Private Const C_SHA512 As Long = 3
'--------------------------------------------------------------
'　SHA256算出関数
'--------------------------------------------------------------
Public Function GetSHA256(ハッシュ値算出範囲 As Range) As Variant
    Application.Volatile
    GetSHA256 = ComputeSHA(C_SHA256, ハッシュ値算出範囲)

End Function
'--------------------------------------------------------------
'　SHA384算出関数
'--------------------------------------------------------------
Public Function GetSHA384(ハッシュ値算出範囲 As Range) As Variant
    Application.Volatile
    GetSHA384 = ComputeSHA(C_SHA384, ハッシュ値算出範囲)

End Function
'--------------------------------------------------------------
'　SHA2512算出関数
'--------------------------------------------------------------
Public Function GetSHA512(ハッシュ値算出範囲 As Range) As Variant
    Application.Volatile
    GetSHA512 = ComputeSHA(C_SHA512, ハッシュ値算出範囲)

End Function

Private Function ComputeSHA(lngType As Long, r As Range) As Variant

    Dim host As New CLRHost
    Call host.Initialize(False)
    host.CLRLoadAssembly ("System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")
    
    Dim str As String
    'Rangeの文字列結合（ワークシート関数のConcatを流用）
    str = Application.WorksheetFunction.Concat(r)
    
    'バイト読み込み
    Dim code() As Byte
    Dim objUTF8 As mscorlib.Object
    Set objUTF8 = host.ToObject(host.CLRCreateObject("System.Text.UTF8Encoding"))
    code = host.CLRInvokeMethod(objUTF8, "GetBytes", str)
    Set objUTF8 = Nothing
    
    'ハッシュ値計算
    Dim hashValue() As Byte
    Dim objSHA As mscorlib.Object
    Select Case lngType
        Case C_SHA256
            Set objSHA = host.ToObject(host.CLRCreateObject("System.Security.Cryptography.SHA256Managed"))
        Case C_SHA384
            Set objSHA = host.ToObject(host.CLRCreateObject("System.Security.Cryptography.SHA384Managed"))
        Case C_SHA512
            Set objSHA = host.ToObject(host.CLRCreateObject("System.Security.Cryptography.SHA512Managed"))
    End Select
    hashValue = host.CLRInvokeMethod(objSHA, "ComputeHash", code)
    Set objSHA = Nothing
    
    '16進数へ変換
    Dim description As String
    
    description = ""
    
    Dim i As Long
    For i = LBound(hashValue()) To UBound(hashValue())
        description = description & Right("0" & Hex(hashValue(i)), 2)
    Next i

    'return
    ComputeSHA = LCase(description)

    Set host = Nothing
End Function