Bitcoin, which has for years been the currency of choice on the so-called dark web, is falling out of favor among criminals. This is not surprising given bitcoin’s sluggish processing times, and law enforcement’s growing ability to track its transactions.

More surprising is what these criminals are turning to instead. Rather than using one of the newer digital currencies with extra privacy features, such as ZCash or Monero, the most popular alternative is the bitcoin clone, Litecoin.

Those are among the findings laid out in a new report by Recorded Future, a threat intelligence company that monitors criminal forums on the dark web where many illegal transactions are arranged. Here is a key paragraph from the report:

Litecoin emerged as the second most popular currency, with 30% of all vendors who implemented alternative payment methods willing to accept it. Dash is closely trailing Litecoin with 20% of the market. Unexpectedly, Bitcoin Cash was the third most common cryptocurrency with 13% of vendors trusting it as a payment method.

The report also notes that Litecoin is especially popular in Russia, while English speaking countries favor Monero, which many people consider all but untraceable. (You can read the full report here.)

In a phone conversation with Fortune, one of the report’s authors, Andrei Barysevich, said he believes there are two main reasons for Litecoin’s popularity. The first is based on its convenience—Litecoin, which is one of the web’s oldest currencies, is available at nearly every online exchange and also processes transactions much faster than bitcoin.

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The other reason for Litecoin’s appeal is that it is supported by makers of so-called “cold storage” wallets like the Ledger Nano S—which are small devices that let owners store their cryptocurrency in a way that is not connected to the Internet.

Barysevich explained this security feature is important to many criminals, especially in Russia, who are worried less about law enforcement than they are about hackers stealing from their wallets.

The report also predicts that Dash will emerge as the next dominant currency in criminal forums. It also adds that, despite the complaints over bitcoin, the original virtual currency still remains the gold standard for most online criminal transactions.