From Rings to Crypto: Is Kiddushin with Bitcoin or Meme Coins valid

I would appreciate if you could share with me any halachic discussions regarding Bitcoin and its relevance to Halacha.

.Thank you for your question

I would like to share with you one such discussion regarding Bitcoin, and that is, what if, a groom decides to be original, and instead of giving a ring to his bride and saying “Harei at mekudeshet li b’taba’at zu,” he takes out his laptop and says, “Harei at mekudeshet li b’Bitcoin zeh,” and then makes a transfer to the bride’s e-wallet—would that be a valid kiddushin

We could argue that since she received a monetary value, it should be considered a valid kiddushin. Or, maybe since the bride didn’t receive anything tangible, like a ring, from her groom, it would not be considered a valid kiddushin

Source #1
The Gemara in Kiddushin (6b) states as follows

תלמוד בבלי מסכת קידושין דף ו עמוד ב
אמר אביי: המקדש במלוה - אינה מקודשת

The Gemara discusses a case where the bride owed the groom money, say $100, and the groom says to the bride, Harei at mekudeshet li b’milveh zu —“You are mekudeshet to me through the money that you owed me

In this case, the Gemara writes that the kiddushin is not valid, and she is not mekudeshet—even though she gained a great deal through the cancellation of the debt. However, since cancellation of the debt is not considered as having received anything new from the groom therefore the kiddushin is not valid

We see from this that there has to be a tangible monetary gain to the bride. The cancellation of the debt, even though it may be a great favor to the bride, is not enough, since it was only a forgiveness of the debt

Source #2
The Gemara in Tractate Kiddushin (47b) writes as follows

תלמוד בבלי מסכת קידושין דף מז עמוד ב
התקדשי לי בשטר חוב, או שהיה לו מלוה ביד אחרים והירשה עליהם, ר"מ אומר: מקודשת, וחכ"א: אינה מקודשת;

The Gemara discusses a case where someone else owed the groom money (not the bride), and the groom says to the bride: Harei at mekudeshet li b’chov zeh —You should be mekudeshet to me through the debt that is owed to me, which I am giving to you.

This case is a machlokes between Rabbi Meir and the Chachamim
Rabbi Meir holds that the kiddushin is valid, while the Chachamim say it is invalid

The Gemara explains the reason why the Chachamim hold it is invalid is, that they are of the opinion that someone who is owed money may still cancel the debt, even after he has sold or transferred it to someone else. Therefore, by giving this debt to the bride—since he still retains the right to cancel it, therefore, it is not considered as having given her something that is completely hers. Thus, the kiddushin is invalid

We can deduct from here that the Chachmim would agree that if the groom were to give a debt to the bride in a way that he no longer has the right to cancel it, it would be a valid kiddushin according to all opinions

So, from here we see that even though the groom didn’t give the bride anything tangible, it would still be a valid kiddushin, since by giving her the debt, he gave her a monetary gain. This is the opinion of Tosafot and the Ran (commentary on the Rif, page 20a)

Source #3
The opinion of the Ramban (Sefer Milchamot on the Rif, Bava Kama, page 18a) is that the reason one cannot be mekadesh with a debt owed to him is because it is considered a davar shelo ba le’olam —something that has not yet materialized

Even though it may be considered as if the bride received monetary benefit, nevertheless, says the Ramban, it is not enough, since it must be that the groom gave her something that was clearly his . In this case, he just gave the bride a right to collect a debt, so practically all he gave her are rights. Therefore, it is not considered as the groom actually giving something to the bride. (In a case of a debt with a physical document, it could possibly be considered as having given her the document.)

In summary
In the case of Bitcoin, since the groom is giving her something which has monetary value so we can say that it is like the case of giving her a debt owed to him, and after he has given it to her, he cannot cancel it in any way, it should therefore be considered a valid kiddushin. (The actual halachic kinyan of the Bitcoin would be through the halachic acquisition of situmta , and that would need to be further discussed if situmta can be used for a mitzvah of Kiddushin, since it may be a valid Kinyan for a business transaction and not a valid Kinyan for a mitzvah de’orytah, see Biur Halacha Hilchot Pesach Siman 445 )

However, according to the Ramban that we mentioned above, it is not enough that the bride receives monetary value, we need the groom to actually give her something tangible . One could then deliberate whether giving Bitcoin is considered something tangible and not a davar shelo ba le’olam . Since Bitcoin has a sort of mining and codes which may classify it as something tangible, however, with regard to meme coins,  that would be more of a reason to say that it is a davar shelo ba le’olam

Wishing you much success

1. 1. Talmud Bavli Kiddushin 6b
   2. Talmud Bavli Kiddushin 47b
   3. Tosfot on Kiddushin 47b
   4. Ran on the Rif, Kiddushin 20a
   5. Ramban, on the Rif, Bava Kama 18a