Банку нужно подтверждение личности.

Because Russian often expresses need with a dative construction.

Literally, Банку нужно подтверждение личности is structured more like:

• To the bank = банку
• is needed = нужно
• identity verification = подтверждение личности

So банку is the person or organization that has the need, and that role is commonly put in the dative case.

Compare:

• Мне нужен паспорт. = I need a passport.
• Банку нужно подтверждение личности. = The bank needs identity verification.

In both sentences, the one who needs something is in the dative:

• мне
• банку

Russian often leaves out to be in the present tense.

So instead of saying something like Банку есть нужно..., Russian simply says:

• Банку нужно подтверждение личности.

Here нужно works as the predicate, so the sentence is complete without another present-tense verb.

A more explicit alternative with a full verb would be:

• Банк требует подтверждение личности. = The bank requires identity verification.

But your original sentence is very natural and common.

Here нужно means needed / necessary.

In this kind of sentence, it expresses necessity:

• Мне нужно время. = I need time.
• Ему нужна помощь. = He needs help.
• Банку нужно подтверждение личности. = The bank needs identity verification.

You can think of it as meaning either:

• needs
• or more literally it is necessary for the bank to have...

Because подтверждение is a neuter singular noun.

The forms change to match the thing that is needed:

• нужен for masculine singular
• нужна for feminine singular
• нужно for neuter singular
• нужны for plural

Examples:

• Мне нужен паспорт. = I need a passport.
• Мне нужна справка. = I need a certificate.
• Мне нужно подтверждение. = I need confirmation.
• Мне нужны документы. = I need documents.

Since подтверждение is neuter singular, the correct form is нужно.

It is in the nominative singular.

In this pattern, the thing that is needed is usually in the nominative:

• Мне нужен паспорт.
• Нам нужна помощь.
• Банку нужно подтверждение личности.

So:

• банку = dative, the one who needs
• подтверждение = nominative, the thing needed

Личности is in the genitive singular.

The noun подтверждение means confirmation / verification, and it is followed by the thing being confirmed, which often goes in the genitive:

• подтверждение адреса = confirmation of address
• подтверждение личности = confirmation of identity
• подтверждение оплаты = confirmation of payment

So:

• подтверждение = confirmation
• личности = of identity

Yes. That is also correct, but it is a different structure.

Compare:

• Банку нужно подтверждение личности.
• Банк нуждается в подтверждении личности.

Both mean roughly the same thing, but the grammar changes:

1. Банку нужно подтверждение личности

   • банку = dative
   • подтверждение = nominative

2. Банк нуждается в подтверждении личности

   • банк = nominative
   • в подтверждении = prepositional after нуждаться в

The first version is often simpler and very common in everyday Russian.

Yes. Russian word order is flexible.

Your sentence:

• Банку нужно подтверждение личности.

could also be rearranged, for example:

• Подтверждение личности нужно банку.

Both are grammatical, but the emphasis changes.

• Банку нужно подтверждение личности.
  This starts with the bank and feels neutral in many contexts.

• Подтверждение личности нужно банку.
  This emphasizes identity verification more.

Russian word order often depends on focus and context, not just grammar.

Yes, it is natural, especially in official or administrative contexts.

It sounds like something you might see or hear in:

• banking
• customer service
• compliance/KYC procedures
• official notices

In conversation, people might also say things like:

• Банку нужен документ, подтверждающий личность.
• Банк просит подтвердить личность.
• Для банка нужно подтверждение личности.

But your original sentence is perfectly normal and appropriately formal.

Not exactly.

• подтверждение личности = confirmation / verification of identity
• удостоверение личности = identity document / ID

So in your sentence, подтверждение личности refers to the process or proof of verifying identity, not necessarily the physical document itself.

For example:

• Банку нужно подтверждение личности.
  The bank needs identity verification.

• Покажите удостоверение личности.
  Show your ID.

This distinction is useful because English often uses ID in a broader way than Russian does.

Yes, that is a helpful literal translation for understanding the grammar.

A word-for-word breakdown is roughly:

• Банку = to the bank
• нужно = is needed / necessary
• подтверждение личности = confirmation of identity

That literal version sounds unnatural in English, but it helps explain why Russian uses the dative банку instead of making банк the subject.

A natural English translation would still be:

• The bank needs identity verification.