Delphi Firemonkey LockBox3 AES-CBC, PC and Android result are different?

  

I need a AES library for devolop Firemonkey Moblie App. I tested ElAES and LockBox3, everything works fine complie to PC, But on FMX Android both library return wrong ciphertext.

Test Data (AES128CBC PKCS5Padding):

plainText: ‘plainText’ – edtPlaintext.Text
key: ‘0000000000000000’ – edtKey.Text
IV: ‘0000000000000000’ – edtIV.Text
cipherText: hex – ‘DD0A2A20616162697B8B4DF53483F1D2’,
base64 – ‘3QoqIGFhYml7i031NIPx0g==’

Test Code:

This is test code reley on LockBox3, related: https://github.com/TurboPack/LockBox3, function ‘EncryptMemory’ return unfixed ciphertext each time on Android, something need to notice?

uses uTPLb_Codec, uTPLb_CryptographicLibrary, uTPLb_Constants, uTPLb_StreamUtils;

type
TCustomPadder = class(TObject)
private
FIV: TBytes;
public
constructor Create(const AIV: TBytes);
procedure OnSetIV(Value: TMemoryStream);
end;

constructor TCustomPadder.Create(const AIV: TBytes);
begin
FIV := AIV
end;

procedure TCustomPadder.OnSetIV(Value: TMemoryStream);
begin
Value.Size := Length(FIV);
Value.Position := 0;
Value.WriteBuffer(FIV, Length(FIV))
end;

function NewCodec(key: TBytes): TCodec;
var
codec: TCodec;
cryptographicLibrary: TCryptographicLibrary;
keyStream: TStream;
padder: TCustomPadder;
begin
cryptographicLibrary := TCryptographicLibrary.Create(nil);
// basic
codec := TCodec.Create(nil);
codec.BlockCipherId := Format(AES_ProgId, [128]);
codec.ChainModeId := CBC_ProgId;
codec.CryptoLibrary := cryptographicLibrary;
codec.StreamCipherId := BlockCipher_ProgId;
// extend
padder := TCustomPadder.Create(bytesof(‘0000000000000000’));
keyStream := TMemoryStream.Create;
keyStream.WriteBuffer(key, Length(key));
keyStream.Position := 0;
codec.OnSetIV := padder.OnSetIV;
codec.InitFromStream(keyStream);
result := codec;
end;

function PKCS5Padding(ciphertext: string; blocksize: integer): string;
var
builder: TStringBuilder;
padding: integer;
i: integer;
begin
builder := TStringBuilder.Create(ciphertext);
padding := blocksize – (builder.Length mod blocksize);
for i := 1 to padding do
begin
builder.Append(Char(padding));
end;
result := builder.ToString;
builder.DisposeOf;
end;

function BytesToHexStr(bytes: TBytes): string;
var
i: integer;
begin
result := ”;
for i := 0 to Length(bytes) – 1 do
result := result + bytes[i].ToHexString(2);
end;

procedure TformAEST.btnEncryptClick(Sender: TObject);
var
codec: TCodec;
plainBytes, cipherBytes: TBytes;
cipherMemory: TStream;
cipherBytesLen: integer;
begin

cipherMemory := TMemoryStream.Create;

plainBytes := bytesof(PKCS5Padding(edtPlaintext.Text, 16));

codec := NewCodec(bytesof(edtKey.Text));
codec.Begin_EncryptMemory(cipherMemory);
codec.EncryptMemory(plainBytes, Length(plainBytes));
codec.End_EncryptMemory;

cipherMemory.Position := 8;
cipherBytesLen := cipherMemory.Size – 8;
SetLength(cipherBytes, cipherBytesLen);
cipherMemory.ReadBuffer(cipherBytes, cipherBytesLen);
edtCiphertext.Text := BytesToHexStr(cipherBytes);
end;

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