echo @openssl_encrypt('Hello, world!', 'AES-256-CBC', 'monday', 0, 'tuesday');

vjhI+ms245e1Pb6SkDsmMQ==

Function AES_256_CBC_Decrypt(base64, key, iv)
	Set aes = CreateObject("System.Security.Cryptography.RijndaelManaged")
	Set utf8 = CreateObject("System.Text.UTF8Encoding")
	Set b64Dec = CreateObject("System.Security.Cryptography.FromBase64Transform")

	aes.key = utf8.GetBytes_4(Left(key & String(32, Chr(0)), 32))
	aes.iv = utf8.GetBytes_4(Left(iv & String(16, Chr(0)), 16))
	base64Bytes = utf8.GetBytes_4(base64)
	encodedBytes = b64Dec.TransformFinalBlock((base64Bytes), 0, LenB(base64Bytes))
	decryptedBytes = aes.CreateDecryptor().TransformFinalBlock((encodedBytes), 0, LenB(encodedBytes))
	AES_256_CBC_Decrypt = utf8.GetString((decryptedBytes))
End Function

WScript.Echo AES_256_CBC_Decrypt("vjhI+ms245e1Pb6SkDsmMQ==", "monday", "tuesday")

Hello, world!

declare @hr int

declare @aes int
execute @hr = sp_OACreate 'System.Security.Cryptography.RijndaelManaged', @aes out
if @hr != 0 throw 50001, @hr, 0

declare @utf8 int
execute @hr = sp_OACreate 'System.Text.UTF8Encoding', @utf8 out
if @hr != 0 throw 50002, @hr, 0 -- Возникает ошибка -2146234334

declare @hr int

declare @utf8 int
execute @hr = sp_OACreate 'System.Text.UTF8Encoding', @utf8 out
if @hr != 0 throw 50002, @hr, 0

declare @aes int
execute @hr = sp_OACreate 'System.Security.Cryptography.RijndaelManaged', @aes out
if @hr != 0 throw 50001, @hr, 0 -- Возникает ошибка -2146234334