Decryption of API Data in BC365 [SAAS]

ishyampandey

Hello Everyone,

I am getting encrypted value with key from API and I need to decrypt the data using that key in bc365 SAAS.
Encryption algo is SHA256. Thanks

ftornero

Hello @ishyampandey,

After a little more digging looks like AES256 is a subset of the Rijndael block cipher and this one it's implemented in the codeunit "Rijndael Cryptography", so I created an app to test this and after some tests with an online tool the combination that works is "Cypher Mode = ECB" and "Padding Mode = PKCS7".

table 50100 EncDec
{
    fields
    {
        field(1; PK; Code[10])
        {

        }
        field(2; Clave; Text[50])
        {
        }
        field(3; Texto2Encrypt; Text[100])
        {

        }
        field(4; Texto2Decrypt; Text[100])
        {

        }
        field(5; Salt; Text[100])
        {

        }
        field(6; Result; Text[100])
        {

        }
        field(7; CypherMode; Option)
        {
            OptionMembers = ECB,CBC,CFB,CTS,OFB;
        }
        field(8; PaddingMode; Option)
        {
            OptionMembers = PKCS7,ANSIX923,ISO10126,Zeros,None;
        }
    }
    keys
    {
        key(Key1; PK)
        {

        }
    }
}

page 50100 Encrypt_Decrypt
{
    PageType = Card;
    SourceTable = EncDec;
    UsageCategory = Administration;
    ApplicationArea = All;
    ModifyAllowed = true;
    DeleteAllowed = false;
    InsertAllowed = false;

    layout
    {
        area(Content)
        {
            field(Clave; Rec.Clave)
            {
                ApplicationArea = All;
                Caption = 'Key';
                trigger OnValidate()
                begin
                    Rijndael.InitRijndaelProvider(Rec.Clave, 128, Format(Rec.CypherMode), Format(Rec.PaddingMode));
                end;
            }
            field(CypherMode; Rec.CypherMode)
            {
                ApplicationArea = All;
                trigger OnValidate()
                begin
                    Rijndael.SetCipherMode(Format(Rec.CypherMode));
                end;
            }
            field(PaddingMode; Rec.PaddingMode)
            {
                ApplicationArea = All;
                trigger OnValidate()
                begin
                    Rijndael.SetPaddingMode(Format(Rec.PaddingMode));
                end;
            }
            field(Texto2Encrypt; Rec.Texto2Encrypt)
            {
                ApplicationArea = All;
                Caption = 'Text2Encrypt';
            }
            field(Texto2Decrypt; Rec.Texto2Decrypt)
            {
                ApplicationArea = All;
                Caption = 'Text2Decrypt';
            }
            field(Result; Rec.Result)
            {
                ApplicationArea = All;
                Editable = false;
            }
        }
    }
    actions
    {
        area(Processing)
        {
            action(Encrypt)
            {
                ApplicationArea = All;
                Promoted = true;
                PromotedCategory = Process;
                PromotedIsBig = true;
                Image = EncryptionKeys;

                trigger OnAction()
                begin
                    if (Rec.Clave <> '') and (Rec.Texto2Encrypt <> '') then begin
                        Rec.Result := Rijndael.Encrypt(Rec.Texto2Encrypt);
                        Rec.Texto2Decrypt := Rec.Result;
                    end;
                end;
            }
            action(Decrypt)
            {
                ApplicationArea = All;
                Promoted = true;
                PromotedCategory = Process;
                PromotedIsBig = true;
                Image = Description;

                trigger OnAction()
                begin
                    if (Rec.Clave <> '') and (Rec.Texto2Decrypt <> '') then begin
                        Rec.Result := Rijndael.Decrypt(Rec.Texto2Decrypt);
                        Rec.Texto2Encrypt := Rec.Result;
                    end;
                end;
            }
        }
    }

    trigger OnOpenPage();
    begin
        Rec.Reset();
        if not Rec.Get() then begin
            Rec.Init();
            Rec.Insert();
        end;
        if Rec.Clave <> '' then
            Rijndael.InitRijndaelProvider(Rec.Clave, 128, Format(Rec.CypherMode), Format(Rec.PaddingMode));
    end;

    var

        Rijndael: Codeunit "Rijndael Cryptography";
}

In this link you can test your results.

https://encode-decode.com/aes-256-ecb-encrypt-online/

Regards

ftornero

Hello @ishyampandey

You can take a look to the Cryptography Management codeunt

https://github.com/microsoft/ALAppExtensions/tree/master/Modules/System/Cryptography Management/src

Regards.

ishyampandey

Hi @ftornero

Thanks for your help.
I am not able to find Cryptography Management CU in Cloud version.
Decrypt function is there but i am not able to use it because it have only single string parameter is asking. I don't know where to use the key to decrypt the value.
In your shared CU i can see there are few function available which are asking for key and value both.
Can you help me bit more regarding this its highly appreciated. Thanks

ftornero

Hello @ishyampandey,

Could you elaborate a little more what is the encrypted data that you get, the key that you have, etc., because you can not decrypt a SHA256 hash.

Regards

ishyampandey

Hi @ftornero, I am getting account no. (KnLoHfEvogSHn4qQ2ar2vj==)
and Key (S@h@y@o@p@t@e@p@I@n@d@e@y@a@2020)
I have to decrypt account no using key.

ftornero

Hello @ishyampandey,

Ok, and what more information the API documentation give to you to decrypt the account no.

Regards

ishyampandey

Hi @ftornero ,
Only encrypted account and key that's it.

ftornero

Hello @ishyampandey,

In your first post you said that encryption algorithm was SHA256, so I assume that there is something more that the API documentation explain.

Regards

ishyampandey

Hi @ftornero,

Yes client said that algo is SHA-256 but they are providing this much only.
Key and encrypted value.
Thanks

ftornero

Hello @ishyampandey,

Then theres is something that is missing because SHA256 can be decrypted because is a hash, to encrypt/decrypt you need something like RSA o PGP.

You need to ask for more information to the API owner.

Regards

ishyampandey

Hi @ftornero,
Thanks, I asked to client and in reply they Said
We are using SHA256 (AES256) algorithm for encryption.
I will update you further about this. Thank you very much
If you have any suggestion regarding new method of encryption which can be easily decrypt please let me know.

ftornero

Hello @ishyampandey,

If the algorithm is AES256 then you need to use an Azure Function o something similar to send the encrypted value and the key and get the decrypted value back, because BC in SaaS don't have the function to do that.

Regards.

ftornero

Hello @ishyampandey,

After a little more digging looks like AES256 is a subset of the Rijndael block cipher and this one it's implemented in the codeunit "Rijndael Cryptography", so I created an app to test this and after some tests with an online tool the combination that works is "Cypher Mode = ECB" and "Padding Mode = PKCS7".

table 50100 EncDec
{
    fields
    {
        field(1; PK; Code[10])
        {

        }
        field(2; Clave; Text[50])
        {
        }
        field(3; Texto2Encrypt; Text[100])
        {

        }
        field(4; Texto2Decrypt; Text[100])
        {

        }
        field(5; Salt; Text[100])
        {

        }
        field(6; Result; Text[100])
        {

        }
        field(7; CypherMode; Option)
        {
            OptionMembers = ECB,CBC,CFB,CTS,OFB;
        }
        field(8; PaddingMode; Option)
        {
            OptionMembers = PKCS7,ANSIX923,ISO10126,Zeros,None;
        }
    }
    keys
    {
        key(Key1; PK)
        {

        }
    }
}

page 50100 Encrypt_Decrypt
{
    PageType = Card;
    SourceTable = EncDec;
    UsageCategory = Administration;
    ApplicationArea = All;
    ModifyAllowed = true;
    DeleteAllowed = false;
    InsertAllowed = false;

    layout
    {
        area(Content)
        {
            field(Clave; Rec.Clave)
            {
                ApplicationArea = All;
                Caption = 'Key';
                trigger OnValidate()
                begin
                    Rijndael.InitRijndaelProvider(Rec.Clave, 128, Format(Rec.CypherMode), Format(Rec.PaddingMode));
                end;
            }
            field(CypherMode; Rec.CypherMode)
            {
                ApplicationArea = All;
                trigger OnValidate()
                begin
                    Rijndael.SetCipherMode(Format(Rec.CypherMode));
                end;
            }
            field(PaddingMode; Rec.PaddingMode)
            {
                ApplicationArea = All;
                trigger OnValidate()
                begin
                    Rijndael.SetPaddingMode(Format(Rec.PaddingMode));
                end;
            }
            field(Texto2Encrypt; Rec.Texto2Encrypt)
            {
                ApplicationArea = All;
                Caption = 'Text2Encrypt';
            }
            field(Texto2Decrypt; Rec.Texto2Decrypt)
            {
                ApplicationArea = All;
                Caption = 'Text2Decrypt';
            }
            field(Result; Rec.Result)
            {
                ApplicationArea = All;
                Editable = false;
            }
        }
    }
    actions
    {
        area(Processing)
        {
            action(Encrypt)
            {
                ApplicationArea = All;
                Promoted = true;
                PromotedCategory = Process;
                PromotedIsBig = true;
                Image = EncryptionKeys;

                trigger OnAction()
                begin
                    if (Rec.Clave <> '') and (Rec.Texto2Encrypt <> '') then begin
                        Rec.Result := Rijndael.Encrypt(Rec.Texto2Encrypt);
                        Rec.Texto2Decrypt := Rec.Result;
                    end;
                end;
            }
            action(Decrypt)
            {
                ApplicationArea = All;
                Promoted = true;
                PromotedCategory = Process;
                PromotedIsBig = true;
                Image = Description;

                trigger OnAction()
                begin
                    if (Rec.Clave <> '') and (Rec.Texto2Decrypt <> '') then begin
                        Rec.Result := Rijndael.Decrypt(Rec.Texto2Decrypt);
                        Rec.Texto2Encrypt := Rec.Result;
                    end;
                end;
            }
        }
    }

    trigger OnOpenPage();
    begin
        Rec.Reset();
        if not Rec.Get() then begin
            Rec.Init();
            Rec.Insert();
        end;
        if Rec.Clave <> '' then
            Rijndael.InitRijndaelProvider(Rec.Clave, 128, Format(Rec.CypherMode), Format(Rec.PaddingMode));
    end;

    var

        Rijndael: Codeunit "Rijndael Cryptography";
}

In this link you can test your results.

https://encode-decode.com/aes-256-ecb-encrypt-online/

Regards

ishyampandey

@ftornero Hi,

Thank you very much, Let me try this by creating an extension. I will update my status.

ishyampandey

@ftornero Hi,
Your solution worked well and I got something good to learn from you. Thank you