Decryption of API Data in BC365 [SAAS]

ishyampandey · 2020-12-29

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 · 2021-01-02

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 · 2020-12-29

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 · 2020-12-30

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 · 2020-12-30

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 · 2020-12-30

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 · 2020-12-30

Hello @ishyampandey,

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

Regards

ishyampandey · 2020-12-30

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

ftornero · 2020-12-30

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 · 2020-12-30

Hi @ftornero,

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

ftornero · 2020-12-30

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 · 2020-12-30

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 · 2020-12-30

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 · 2021-01-02

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 · 2021-01-03

@ftornero Hi,

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

ishyampandey · 2021-01-11

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

Decryption of API Data in BC365 [SAAS]

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