SEED SPLITTING AND FIRMWARE EXTENSION FOR SECURE CRYPTOCURRENCY KEY BACKUP, RESTORE, AND TRANSACTION SIGNING PLATFORM APPARATUSES, METHODS AND SYSTEMS

• US 20180367316A1
• Filed: 05/18/2018
• Published: 12/20/2018
• Est. Priority Date: 07/14/2015
• Status: Active Grant

• Current Assignee: FMR LLC
• Original Assignee: FMR LLC
• Inventors: Cheng, Gang, Tsitrin, Vladimir, McGuire, Thomas Stephen
• Granted Patent: US 10,778,439 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 21/52 during program execution, e.g. stack integrity ; Preventing unwanted data erasure; Buffer overflow
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: H04L 2209/12 Details relating to cryptographic hardware or logic circuitry
• CPC Class Codes: H04L 2209/127 Trusted platform modules [TPM]
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/0643 Hash functions, e.g. MD5, SHA, HMAC or f9 MAC
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/085 Secret sharing or secret splitting, e.g. threshold schemes
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853
• CPC Class Codes: H04L 9/3239 involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/50 using hash chains, e.g. blockchains or hash trees

Abstract

The Seed Splitting and Firmware Extension for Secure Cryptocurrency Key Backup, Restore, and Transaction Signing Platform Apparatuses, Methods and Systems (“SFTSP”) transforms transaction signing request, key backup request, key recovery request inputs via SFTSP components into transaction signing response, key backup response, key recovery response outputs. A transaction signing request message for a transaction is received by a first HSM and includes an encrypted second master key share from a second HSM whose access is controlled by M-of-N authentication policy. The encrypted second master key share is decrypted. A first master key share is retrieved. A master private key is recovered from the master key shares. A transaction hash and a keychain path is determined. A signing private key for the keychain path is generated using the recovered master private key. The transaction hash is signed using the signing private key, and the generated signature is returned.

Claims

1. A transaction signing apparatus, comprising:

a memory;

a component collection in the memory, including;

a secure firmware transaction signing component implemented by a first hardware security module (HSM);

a processor disposed in communication with the memory, and configured to issue a plurality of processing instructions from the component collection stored in the memory,

wherein the processor issues instructions from the secure firmware transaction signing component, stored in the memory, to;

receive, via at least one processor, by the first HSM, a transaction signing request message for a transaction from a transaction signing server (TSS), wherein the transaction signing request message includes an encrypted second master key share associated with a second HSM;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a private key decryption key corresponding to a public key encryption key previously provided by the first HSM to the TSS for the second HSM, wherein the encrypted second master key share is encrypted using the public key encryption key by the second HSM;

decrypt, via at least one processor, by the first HSM, the encrypted second master key share using the retrieved private key decryption key;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a first master key share;

recover, via at least one processor, by the first HSM, a master private key from the first master key share and the decrypted second master key share using a secret sharing method;

determine, via at least one processor, by the first HSM, a transaction hash and a keychain path associated with the transaction signing request message;

generate, via at least one processor, by the first HSM, a signing private key for the determined keychain path using the recovered master private key;

sign, via at least one processor, by the first HSM, the determined transaction hash using the generated signing private key to generate a signature; and

return, via at least one processor, the generated signature.

2. The apparatus of claim 1, wherein the first HSM is a PCIe appliance.

3. The apparatus of claim 1, wherein the second HSM is a USB appliance communicatively coupled to the TSS via USB.

4. The apparatus of claim 1, wherein the second HSM includes an authentication entry device.

5. The apparatus of claim 4, wherein the second HSM provides the encrypted second master key share to the TSS upon obtaining separate credentials via the authentication entry device from a predetermined number of people.

6. The apparatus of claim 5, wherein the second HSM enforces M-of-N security policy for exporting the encrypted second master key share, wherein access to the second HSM is controlled by M-of-N authentication policy.

7. The apparatus of claim 1, wherein the private key decryption key and the public key encryption key are predefined for the first HSM.

8. The apparatus of claim 1, wherein the private key decryption key and the public key encryption key are generated dynamically each time a transaction signing request message is received.

9. The apparatus of claim 1, wherein the transaction signing request message is an API call to a method exposed by the secure firmware transaction signing component.

10. The apparatus of claim 1, wherein the secret sharing method is Shamir'"'"'s Secret Sharing.

11. The apparatus of claim 1, wherein the signing private key is generated using a Bip32-based deterministic key derivation procedure.

12. The apparatus of claim 1, further, comprising:

the processor issues instructions from the secure firmware transaction signing component, stored in the memory, to;

wipe, via at least one processor, temporary private key data from the memory after generating the signature.

13. The apparatus of claim 12, wherein the temporary private key data includes the private key decryption key, the public key encryption key, the encrypted second master key share, the decrypted second master key share, the recovered master private key, and the generated signing private key.

14. The apparatus of claim 1, wherein the transaction hash is signed in accordance with the hashing algorithm utilized by the Bitcoin protocol.

15. The apparatus of claim 1, wherein the signature is returned in Distinguished Encoding Rules format.

16. A processor-readable transaction signing non-transient physical medium storing processor-executable components, the components, comprising:

a component collection stored in the medium, including;

a secure firmware transaction signing component implemented by a first hardware security module (HSM);

wherein the secure firmware transaction signing component, stored in the medium, includes processor-issuable instructions to;

receive, via at least one processor, by the first HSM, a transaction signing request message for a transaction from a transaction signing server (TSS), wherein the transaction signing request message includes an encrypted second master key share associated with a second HSM;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a private key decryption key corresponding to a public key encryption key previously provided by the first HSM to the TSS for the second HSM, wherein the encrypted second master key share is encrypted using the public key encryption key by the second HSM;

decrypt, via at least one processor, by the first HSM, the encrypted second master key share using the retrieved private key decryption key;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a first master key share;

recover, via at least one processor, by the first HSM, a master private key from the first master key share and the decrypted second master key share using a secret sharing method;

determine, via at least one processor, by the first HSM, a transaction hash and a keychain path associated with the transaction signing request message;

generate, via at least one processor, by the first HSM, a signing private key for the determined keychain path using the recovered master private key;

sign, via at least one processor, by the first HSM, the determined transaction hash using the generated signing private key to generate a signature; and

return, via at least one processor, the generated signature.

17. A processor-implemented transaction signing system, comprising:

secure firmware transaction signing component means implemented by a first hardware security module (HSM), to;

receive, via at least one processor, by the first HSM, a transaction signing request message for a transaction from a transaction signing server (TSS), wherein the transaction signing request message includes an encrypted second master key share associated with a second HSM;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a private key decryption key corresponding to a public key encryption key previously provided by the first HSM to the TSS for the second HSM, wherein the encrypted second master key share is encrypted using the public key encryption key by the second HSM;

decrypt, via at least one processor, by the first HSM, the encrypted second master key share using the retrieved private key decryption key;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a first master key share;

recover, via at least one processor, by the first HSM, a master private key from the first master key share and the decrypted second master key share using a secret sharing method;

determine, via at least one processor, by the first HSM, a transaction hash and a keychain path associated with the transaction signing request message;

generate, via at least one processor, by the first HSM, a signing private key for the determined keychain path using the recovered master private key;

sign, via at least one processor, by the first HSM, the determined transaction hash using the generated signing private key to generate a signature; and

return, via at least one processor, the generated signature.

18. A processor-implemented transaction signing method, comprising:

executing processor-implemented secure firmware transaction signing component instructions implemented by a first hardware security module (HSM), to;

receive, via at least one processor, by the first HSM, a transaction signing request message for a transaction from a transaction signing server (TSS), wherein the transaction signing request message includes an encrypted second master key share associated with a second HSM;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a private key decryption key corresponding to a public key encryption key previously provided by the first HSM to the TSS for the second HSM, wherein the encrypted second master key share is encrypted using the public key encryption key by the second HSM;

decrypt, via at least one processor, by the first HSM, the encrypted second master key share using the retrieved private key decryption key;

retrieve, via at least one processor, from the first HSM'"'"'s tamper-proof storage, a first master key share;

recover, via at least one processor, by the first HSM, a master private key from the first master key share and the decrypted second master key share using a secret sharing method;

determine, via at least one processor, by the first HSM, a transaction hash and a keychain path associated with the transaction signing request message;

generate, via at least one processor, by the first HSM, a signing private key for the determined keychain path using the recovered master private key;

sign, via at least one processor, by the first HSM, the determined transaction hash using the generated signing private key to generate a signature; and

return, via at least one processor, the generated signature.