Ttdfjt

I did migration Magento 1 to Magento 2.3.0 all is good but when I create customer form both of side (front and admin) I got the error related to decrypt even I can not edit the customer when I click on save same error has occurred.

error is :

Fatal error: Uncaught TypeError: Return value of
MagentoFrameworkEncryptionAdapterSodiumChachaIetf::decrypt() must
be of the type string, boolean returned in
public_html/vendor/magento/framework/Encryption/Adapter/SodiumChachaIetf.php:68
Stack trace: #0
public_html/vendor/magento/framework/Encryption/Encryptor.php(358):
MagentoFrameworkEncryptionAdapterSodiumChachaIetf->decrypt('"x10x88x8ExB5x851;HxB1x12xE1aaP...')

#1 /public_html/vendor/dotmailer/dotmailer-magento2-extension/Helper/Data.php(744):
MagentoFrameworkEncryptionEncryptor->decrypt('IhCIjrWFMTtIsRL...')

#2 /public_html/vendor/dotmailer/dotmailer-magento2-extension/Helper/Data.php(203):
DotdigitalgroupEmailHelperData->getApiPassword(Object(MagentoStoreModelWebsiteInterceptor))

#3 public_html/vendor/dotmailer/dotmailer-magento2-extens
in
/public_html/vendor/magento/framework/Encryption/Adapter/SodiumChachaIetf.php on line 68

Go to this file:

vendor/magento/framework/Encryption/Adapter/SodiumChachaIetf.php

And Update Below Code:

$plainText = sodium_crypto_aead_chacha20poly1305_ietf_decrypt(
 $payload,
 $nonce,
 $nonce,
 $this->key
 );
 if ($plainText == false)
 
 return "";
 
 return $plainText;

Looks like you are using the wrong crypt key.

You should keep the key from your previews configuration:

app/etc/local.xml [Magento 1.x]

<?xml version="1.0"?>
<config>
 <global>
 <install>
 <date>date</date>
 </install>
 <crypt>
 <key>123456_same_old_key_7890</key>
 </crypt>
[...]

And replace the new one in the new project:

app/etc/env.php [Magento 2.x]

<?php
[...],
'crypt' => [
 'key' => '123456_same_old_key_7890'
],
[...]

Source: https://github.com/magento/magento2/issues/19590

Go to this file:

vendor/magento/framework/Encryption/Adapter/SodiumChachaIetf.php

And update below code:

 public function decrypt(string $data): string
 
 $nonce = mb_substr($data, 0, SODIUM_CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES, '8bit');
 $payload = mb_substr($data, SODIUM_CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES, null, '8bit');

 $plainText = sodium_crypto_aead_chacha20poly1305_ietf_decrypt(
 $payload,
 $nonce,
 $nonce,
 $this->key
 );

 return (string) $plainText;
 

Just change the function return type:
From

return $plainText

to

return (string) $plainText