Crypto Asset LawFamily LawInformation Technology LawInheritance LawShould a private key be included in a will?

The private key or seed phrase must not be written in plain text within the will. The main reason for this is that the will becomes accessible to certain individuals and authorities following the testator’s death, whereas the private key must be kept secret in accordance with the security model.

Anyone who knows the private key can effectively control the assets held at the relevant blockchain address. The seed phrase, on the other hand, is recovery information used in most wallets to regenerate private keys. Therefore, the compromise of the seed phrase usually means that the wallet and the assets within it are completely lost to the testator’s control.

The issue here is not merely whether the will is valid. The real issue is the structural incompatibility between the disclosure of a testamentary disposition and the protection of a cryptographic secret.

The Legal Regime for the Safekeeping and Opening of Wills

Official Will

Under the Turkish Civil Code, a will may be made in a formal manner, in the testator’s own handwriting, or orally. A formal will is drawn up by a public official in the presence of two witnesses. The public official may be a justice of the peace, a notary, or another official authorised by law.

If a formal will is drawn up by a notary, it is kept at the notary’s office and is recorded within the notarial registry system. The Notaries Act requires notaries to keep wills either in open or sealed form and to draw up a record to that effect. The notary is not the authority that delivers the will directly to the heirs upon death. Specific notification and delivery mechanisms come into play.

Handwritten will

A handwritten will is a document written entirely in the testator’s own handwriting from beginning to end, dated and signed by them. This will may be deposited with a notary, a magistrate or an authorised official for safekeeping, either in an open or sealed form.

Storing a handwritten will in a sealed envelope may prevent anyone from reading the text until the will is opened. However, this does not mean that the document will be subject to no access mechanism whatsoever during the testator’s lifetime. Access to the document arises at various stages, such as the registration of the will, the notification of death, the handover of the document to the competent authority and the opening of the will.

Delivery and access after death

The Turkish Civil Code stipulates that a will coming into possession after the testator’s death must be handed over to the magistrate, regardless of whether it is valid or not. The person who drew up, kept or otherwise held the will is under an obligation to hand it over upon learning of the death.

This regime is intended not to keep the will secret, but to ensure it is legally processed after death. Consequently, writing the private key openly in the will may lead to the secret being revealed at the very stage when the access procedure begins.

Risks of Including the Seed Phrase in a Will

Access to notarial records and the safekeeping process

The Notaries Act requires notaries to store wills, whether submitted openly or in sealed form, and to draw up the relevant records. Furthermore, notaries ensure that the stored wills and testamentary dispositions drawn up by the notary’s office are handed over to the Public Prosecutor’s Office for delivery to the competent magistrate upon notification of the testator’s death.

The critical distinction here is as follows: Even if a will is kept in a sealed envelope, the fact that the secret is ultimately explicitly stated in the text of the will creates the risk that the seed phrase may become legible when the document is opened by the competent authorities or when a copy is produced.

Risk posed by registry and notary staff

Staff involved in notarial procedures may come into contact with the document during its physical handling, filing, registration, scanning, the production of copies or the handover process. It should not be assumed that these individuals will act maliciously. However, private key security is of such high sensitivity that it cannot rely solely on the presumption of good faith.

The disclosure of a bank account number does not have the same legal and technical consequences as the disclosure of a private key. An account number alone may not be sufficient to empty the account. By contrast, a seed phrase, when combined with the appropriate wallet software and network knowledge, can facilitate the transfer of assets.

Breach of a notary’s office or data infrastructure

The possibility of a breach in the physical or electronic processes involving documents held at a notary’s office creates a systemic risk if the seed phrase is stored at a single point. Even if a will exists solely on paper, the security of registration details, scanned copies, transaction records or the circulation of documents remains of particular importance.

The vulnerability here is not a breach of the blockchain. The risk lies in the private key being written in plain text on a document outside the blockchain. Whilst transactions on the blockchain are immutable, if the private key is compromised, an attacker could carry out transactions as if they were an authorised user.

Disclosure during court proceedings

The will is submitted to the probate court after death and is examined by the judge. Access to the document may arise during the hearing of interested parties, the safeguarding of the estate, the opening of the will and the validity check.

The extent to which the will is disclosed to the parties, heirs or other interested parties in the case may vary depending on the specific case and procedural decisions. However, the inclusion of the private key in the court file increases the risk of the secret becoming known to a wider circle. It should be noted that there is as yet limited established and published case law from the Court of Cassation or Regional Courts of Appeal regarding how the private keys of crypto-assets should be protected within a will file.

Time-Locked Smart Contract

The purpose of a time-locked smart contract is to prevent the transfer of crypto assets for a specific period, or to ensure they can only be transferred to a specific address once a specified date, block height or condition is met.

Various technical models may be used for this purpose. For example, the assets may be sent to a contract that the testator cannot withdraw from alone. The contract may preserve the testator’s right of revocation for a specific period; at the end of this period, it may enable transfer to the designated beneficiary’s address or to a multi-signature structure.

This structure may not require the private key to be included in the will. However, the testator’s date of death may not be technically and definitively known by the blockchain itself. An external data provider, a trusted party or a separate governance mechanism may be required to verify the death. If this person or system malfunctions, the assets may be transferred prematurely, may not be transferred at all, or may be sent to the wrong address.

Under Turkish law, it is not acceptable for a time-locked smart contract to serve as a will in its own right. Matters such as the form of dispositions upon death, the protection of heirs, reserved shares, the revocation of a will, and issues of legal capacity and defects of consent cannot be resolved by code alone.

For this reason, a smart contract can be designed not as a substitute for a legally valid will, but as a mechanism supporting the technical execution of the will. It must also be assessed whether the transfer effected by the code constitutes a valid devolution under inheritance law, a transaction carried out prior to death, a conditional disposition, or an asset that must be included in the estate.

Notarial Deposit and Encrypted Envelope

Under the Notaries Act, notaries may hold open or sealed wills. Furthermore, among their duties are the performance of legal acts not assigned by law to another authority, and the authentication of elements such as signatures, seals or dates on documents prepared externally and submitted in accordance with the law.

Accordingly, a practical approach is to store an encrypted file or a sealed envelope rather than writing down the seed phrase directly. The text inside the envelope may also be encrypted with a strong password. The will may simply contain the legal and operational instructions on how to access the encrypted file.

The weakness of this method lies in where the encryption password is kept. If the password is also written in the will, the problem arises again. If the password is given to the beneficiary in advance, there is a risk of unauthorised access whilst the testator is still alive. If it is held by a separate individual, there is a risk that this person may die, go missing or refuse to cooperate.

Notarial custody is also not a technical maintenance service. The notary is not obliged to test whether the wallet is functioning, whether the seed phrase is correct, whether it covers assets on a specific network, or whether the encrypted file can be opened in the future. Therefore, the safekeeping of the envelope does not, in itself, resolve issues of technical continuity and verification.

Shamir Secret Sharing and Partial Storage

Shamir Secret Sharing is a cryptographic method that allows a single secret to be divided into multiple parts, with the secret only being reconstructed when a specific number of parts are brought together.

For example, the seed phrase itself, or the secret used to decrypt it, can be divided into five parts, and the reconstruction threshold can be set to three. In this case, the master secret cannot be obtained without combining any three of the five parts.

A will may specify who holds which fragments, under what threshold they are to be combined, and which verification procedure the beneficiaries must follow. However, including all the fragments within the will itself negates the security advantage of the split structure.

In this model, the physical or electronic security of each fragment must be ensured separately. If a fragment is lost, the threshold may not be met. If several of the individuals holding the fragments act in concert, the secret may be revealed. Furthermore, the heirs must be able to combine the fragments without making any technical errors.

Which Scenario for Which Profile?

Heirs with low digital literacy

In this profile, a purely technical smart contract or Shamir Secret Sharing structure may not be understood. An encrypted envelope may seem more comprehensible. Conversely, decryption, wallet setup and network selection may still require technical assistance. Therefore, the will should contain not only the secret but also operational instructions explaining on which networks the assets are held, thereby preventing the heirs from making mistakes.

A testator with assets in multiple countries

Exchanges, custodians, hardware wallets and bank accounts located in multiple countries may be subject to different legal systems. A single Turkish notarial file does not automatically resolve access or inheritance procedures for accounts in foreign countries.

In this scenario, fragmented custody may be distributed amongst trusted individuals or institutions in different countries. However, data protection, inheritance tax, the form of foreign wills and local account closure procedures must also be examined.

Cases involving minor heirs

A minor heir may lack the legal and factual capacity to use the private key directly. Bequeathing the key directly to a minor may create issues regarding the management and representation of the estate. Matters of guardianship, curatorship, trusteeship and reserved shares must be linked to the technical transfer plan.

In such cases, rather than transferring assets directly to a wallet address, multi-signature or split-key structures—where access is contingent upon the approval of multiple adults and authorised persons—may be considered. However, these structures do not automatically fulfil the formal requirements of a will or substitute for the minor’s right to inheritance.

To summarise, writing the private key or seed phrase in plain text within the will poses a serious security risk due to the chain of access created by the will’s storage and subsequent handover to the probate court following death. A sealed will may reduce the likelihood of the document being read whilst the testator is alive; however, it does not eliminate the process of handing it over to the competent authorities and having it examined after death.

Time-locked smart contracts, encrypted envelopes held in notarial custody, and Shamir’s Secret Sharing offer different risk distributions. None of these, on their own, fully resolves the formal requirements of inheritance law, the reserved share, the protection of minor heirs, or technical operational risks. There is as yet no established case law in Turkish law recognising that these technical structures replace a will.