If you have cryptocurrency on an exchange, you’ve probably enabled two-factor authentication. Good for you. But there’s one question most people don’t ask themselves: what type of 2FA are you using?
Because not all verification methods are created equal. And choosing the wrong one can leave you just as vulnerable as not having one at all.
SMS-based two-factor authentication (2FA) remains the most common method used by exchanges worldwide. It is also, by far, the most vulnerable. In 2024, attacks exploiting this vulnerability skyrocketed by 1.055% in the United Kingdom in a single year. In the United States, a cryptocurrency exchange was ordered to pay $33 million after a single attack of this kind drained a user’s cryptocurrency account.
The difference between SMS and an authentication app isn't just a minor technical detail. It's the difference between a security lock and a key hidden under the doormat.
What is 2FA and why does it exist?
2FA (two-factor authentication) is an extra layer of security that complements your password. The idea is simple: to access your account, you need something you know (your password) plus something you have (a one-time code).
The purpose is clear: even if someone steals your password, they still can’t log in without that second factor. On cryptocurrency exchanges, where there is no central bank to reverse fraudulent transactions, this extra layer of security is not optional. It’s the difference between recovering your funds or losing them forever.
The problem is that not all 2FA methods offer the same level of actual protection.
How SMS 2FA Works (and Where It Falls Short)
When you enable 2FA via SMS, the exchange sends you a 6-digit code via text message every time you log in or perform a sensitive transaction. It seems secure. And for years, it was—relatively speaking.
The weak link isn't the technology. It's the telecommunications provider.
For the SMS to reach you, your carrier needs to know which SIM card you're using. And that system has a vulnerability known as SIM swapping: An attacker calls your carrier, impersonates you, and gets them to port your phone number to a SIM card that they control.
From that point on, all text messages sent to you—including verification codes from your exchange—go directly to the attacker. Meanwhile, you’ll find that your phone loses signal without knowing why.
The entire process can take less than 30 minutes. By the time you notice it, it's already too late.
The numbers leave no room for doubt
The data from the past two years paint a troubling picture:
- SIM swapping attacks in the United Kingdom increased by 1.055% between 2023 and 2024, rising from 289 cases to nearly 3,000
- In the United States, the FBI recorded nearly $26 million in direct losses due to this type of attack in 2024 alone
- SIM swapping attacks accounted for 19% of hacks targeting exchanges in 2025
- In March 2025, the carrier T-Mobile was ordered to pay $33 million following an attack that drained approximately $38 million in cryptocurrency from a single user
And these are just the reported cases. Experts estimate that most go unreported.
How app-based 2FA works (and why it's different)
Authentication apps like Google Authenticator, Authy, or Microsoft Authenticator work in a completely different way. Instead of relying on your mobile carrier, they generate codes directly on your device using a mathematical algorithm synchronized with the exchange’s server.
The key is that those codes are generated offline, with no internet connection or cellular network. There are no messages to intercept. There are no carriers to trick. The code exists only on your phone and expires in 30 seconds.
To steal that code, an attacker would need to have physical access to your device or install malware on it. These attacks are significantly more complex and costly to carry out than simply calling a service provider.
Head-to-Head Comparison: SMS vs. Authentication App
| Characteristic | 2FA via SMS | Authentication app |
|---|---|---|
| How the code is generated | Sent by your carrier | Generated locally on your device |
| Requires an internet connection | Yes (mobile network) | No (works offline) |
| Vulnerable to SIM swapping | Yes | No |
| Vulnerable to phishing | Partially | More durable |
| Works without a signal | No | Yes |
| Security level | Basic | High |
| Difficulty with configuration | Very easy | Easy |
The conclusion is clear: the authentication app is superior in virtually every relevant way. The only argument in favor of SMS is the initial convenience, which disappears as soon as you set up the app just once.
The most secure method of all: physical security keys (FIDO2)
While app-based 2FA is already much better than SMS, there’s a third level that goes even further: physical security keys compatible with the FIDO2 standard, such as YubiKeys.
These devices, which are about the size of a USB flash drive, generate a unique cryptographic signature every time you plug them in. There is no code to copy or steal. An attacker would need to physically have the key in their possession.
This is the recommended method for portfolios with large amounts. The downside is the cost (between 30 and 100 euros) and the fact that not all exchanges support it yet. Kraken and Coinbase are among those that do.
For most users, the authentication app offers a balance of convenience and security that is hard to beat. Physical keys are the next step for those who handle significant amounts of money.
Which exchanges does each system use by default?
Not all exchanges make it equally easy to switch to more secure methods:
- Binance: It offers 2FA via SMS, Google Authenticator, and physical security keys. They strongly recommend using the app.
- Kraken: Supports SMS, authentication apps, and FIDO2 keys. One of the exchanges with the best security track record in the industry.
- Coinbase: supports SMS, an authentication app, and physical keys. In 2025, it suffered a social engineering attack that compromised some users' data, although this was not related to 2FA.
- Bitvavo: offers authentication via app and SMS. Widely used in Europe due to its regulation under MiCA.
- Bit2Me: Supports 2FA via app; highly recommended as it is the only Spanish exchange with full MiCA licensing.
If you use any of these exchanges and have SMS verification enabled, you can switch to an authentication app in less than 5 minutes through your account's security settings.
Step-by-Step Guide to Enabling 2FA via the App
The process is virtually the same on all exchanges:
- Download Google Authenticator or Authy on your phone (both are free)
- Go to the security settings on your exchange
- Look for the «Two-Step Verification» or «2FA» option»
- Select «Authentication app» instead of SMS
- Scan the QR code shown on the screen using the app
- Enter the 6-digit code generated by the app to confirm
Important note: This remains the only confirmed hack that has directly affected the exchange.
The mistake many people make when setting up 2FA
Enabling 2FA is the first step, but there’s a common mistake that undermines its effectiveness: linking account recovery to the same phone number you use for SMS.
If an attacker performs SIM swapping on your number, they can intercept not only verification SMS messages but also password recovery messages. As a result, they can take control of your account even if you have 2FA enabled via an app, as long as the recovery method is still set to SMS.
The solution is to check the recovery settings for each exchange and make sure they don't rely solely on your phone number.
Conclusion: The simplest change with the greatest impact on your safety
When it comes to security, few decisions offer such a favorable balance between effort and results as switching from SMS-based two-factor authentication (2FA) to an authentication app. Five minutes of setup can eliminate one of the most commonly exploited attack vectors in the crypto sector today.
SMS-based two-factor authentication isn't useless. It's infinitely better than having no additional verification at all. But in an environment where SIM swapping attacks have increased more than tenfold in a single year, relying on it as the sole security measure for a cryptocurrency account is an avoidable risk.
The authentication app is the minimum recommended standard. If you hold significant amounts on an exchange, adding a physical security key is the next logical step.
Because in the world of cryptocurrency, unlike traditional banking, there is no customer service department that can undo what has already happened.
Legal Notice: This article is for informational purposes only and does not constitute financial advice or investment recommendations. Investing in cryptocurrencies involves a high level of risk. Always consult with a qualified professional before making investment decisions.