ECDP: Elliptic Curve Data Protocol

Internet-Draft	ECDP	November 2024
Ruas	Expires 19 May 2025	[Page]

Abstract

This document specifies the Elliptic Curve Data Protocol (ECDP), a peer-to-peer (P2P) communication protocol tailored for decentralized networks. ECDP utilizes elliptic curve cryptography (ECC) for encryption, employs the Elliptic Curve Digital Signature Algorithm (ECDSA) for message authentication, and leverages the Diffie-Hellman key exchange using elliptic curves for secure session initialization. The protocol supports a variety of elliptic curves (e.g., secp256k1, secp384r1) with varying key sizes, and is designed to operate over both TCP and UDP. Additionally, it utilizes SHA-256 or SHA-512 for cryptographic hash verification to ensure message integrity.¶

About This Document

This note is to be removed before publishing as an RFC.¶

The latest revision of this draft can be found at https://isakruas.github.io/ecdp/draft-ruas-cfrg-ecdp.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ruas-cfrg-ecdp/.¶

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1. Introduction

P2P networks are widely used for data exchange but often face challenges related to security and data integrity. ECDP addresses these issues by implementing strong cryptographic measures and robust authentication mechanisms. ECDP is designed for scalability and security by enabling nodes to communicate indirectly through a network pool.¶

To enhance the security and integrity of the messages exchanged, the protocol employs elliptic curve cryptography (ECC) with various well-established curves, as well as the SHA-256 and SHA-512 algorithms for cryptographic hash functions.¶

The protocol dynamically supports different ECC key lengths, ensuring flexibility and forward compatibility with future developments in elliptic curve cryptography.¶

3. Goals of the Protocol

The protocol MUST facilitate secure communication between nodes through a pool network.¶
The protocol MUST ensure data integrity and confidentiality of the messages transmitted.¶
The protocol MUST authenticate messages using elliptic curve signature schemes, ensuring their origin and integrity.¶
The protocol MUST be extensible and support future advances in cryptographic techniques.¶
The protocol SHOULD be scalable, able to operate in decentralized large-scale P2P networks.¶
The protocol MUST support multiple key sizes for flexible elliptic curve operations.¶

4. Supported Algorithms

ECDP relies on a variety of standardized and widely used algorithms to ensure secure, authenticated, and efficient communication.¶

4.1. 4.1 Cryptography

4.1.1. 4.1.1 Supported Elliptic Curves

ECDP supports the following elliptic curves for encryption, Diffie-Hellman key exchange, and signing operations (ECDSA):¶

secp192k1¶
secp192r1¶
secp224k1¶
secp224r1¶
secp256k1¶
secp256r1¶
secp384r1¶
secp521r1¶

Each curve corresponds to a distinct key size. To accommodate different security levels, the protocol includes a parameter for indicating the key size used in message operations. Implementations MUST support secp256k1, secp256r1, and secp384r1 as a minimum requirement. Support for other curves is RECOMMENDED for greater flexibility and stronger cryptography when necessary.¶

4.1.2. 4.1.2 Supported Cryptographic Hash Algorithms

ECDP uses cryptographic hash functions for various integrity checks, including checksums and digital signatures.¶

Supported hash functions include:¶

SHA-256 (RECOMMENDED)¶
SHA-512 (OPTIONAL for longer data integrity verification)¶

Implementations MUST support SHA-256 as a minimum requirement.¶

6. Message Structure

6.1. 5.1 Base Message Structure

The base structure contains fields that are common across various message types, with extensions for specific needs. Messages are routed through a pool network to enhance scalability and security.¶

Table 1
Field	Description	Size (bytes)
Protocol Version	Identifies the version of the ECDP protocol	1
Message Type	Indicates the type of message	1
Key Size	Indicates the ECC key size used (e.g., 192, 224, 256, 384, 521 bits)	2
Sender ECC Public Key	Public key of the sending node	Variable (based on key size)
Receiver ECC Public Key	Public key of the receiving node (if applicable)	Variable (based on key size)
Nonce	Random number to prevent replay attacks	8
Encrypted Data	Content of the message encrypted using ECC	Variable
Signature	Digital signature of the sender (ECDSA)	Variable (based on key size)

In this structure: - Key Size is a 2-byte field that indicates the key size in bits (e.g., 192, 224, 256, 384, 521). This allows both endpoints to use flexible key sizes as per their security requirements.¶

6.2. 5.2 Handshake (0x01)

Table 2
Field	Description	Size (bytes)
Protocol Version	Identifies the version of the ECDP protocol	1
Message Type	Set to Handshake (0x01)	1
Key Size	Indicates the ECC key size used	2
Sender ECC Public Key	Public key of the sending node	Variable
Receiver ECC Public Key	Public key of the receiving node	Variable
Nonce	Random number to prevent session replay	8
Node Identifier	Unique ID of the node (e.g., hash of the public key)	32
Node Capability	Information about bandwidth and supported data types	4
Signature	Digital signature of the sender (ECDSA)	Variable

6.3. 5.3 Data Transfer (0x02)

Table 3
Field	Description	Size (bytes)
Protocol Version	Identifies the version of the ECDP protocol	1
Message Type	Set to Data Transfer (0x02)	1
Key Size	Indicates the ECC key size used	2
Sender ECC Public Key	Public key of the sending node	Variable
Receiver ECC Public Key	Public key of the receiving node	Variable
Nonce	Exclusive random number for the session	8
Encrypted Data	Message content encrypted using ECC	Variable
Checksum	Cryptographic hash (SHA-256 or SHA-512) for data integrity verification	32 or 64
Signature	Digital signature of the sender (ECDSA)	Variable

6.4. 5.4 Acknowledgment (Ack) (0x03)

Table 4
Field	Description	Size (bytes)
Protocol Version	Identifies the version of the ECDP protocol	1
Message Type	Set to Acknowledgment (0x03)	1
Nonce	Random number corresponding to the session	8
Message Hash	Hash of the received data message (SHA-256 or SHA-512)	32 or 64
Status	Indicates Success (0x00) or Error (0x01)	1

6.5. 5.5 Data Request (0x04)

Table 5
Field	Description	Size (bytes)
Protocol Version	Identifies the version of the ECDP protocol	1
Message Type	Set to Data Request (0x04)	1
Key Size	Indicates the ECC key size used	2
Sender ECC Public Key	Public key of the requesting node	Variable
Receiver ECC Public Key	Public key of the data-holding node	Variable
Nonce	Random number for the session	8
Data Identifier	Unique hash or ID of the requested data (using SHA-256, SHA-512)	32 or 64
Signature	Digital signature of the sender (ECDSA)	Variable

7. Security Considerations

ECDP employs ECC for secure communication between nodes, with messages authenticated through ECDSA. The inclusion of a Key Size field allows nodes to negotiate and use varying key lengths based on the curve chosen, ensuring flexibility in security levels.¶

Nonces are used to prevent replay attacks. The protocol uses the Diffie-Hellman key exchange over elliptic curves for secure session initialization. The following elliptic curves are supported, with corresponding key sizes:¶

secp192k1 (192-bit)¶
secp192r1 (192-bit)¶
secp224k1 (224-bit)¶
secp224r1 (224-bit)¶
secp256k1 (256-bit) (RECOMMENDED)¶
secp256r1 (256-bit) (RECOMMENDED)¶
secp384r1 (384-bit) (RECOMMENDED)¶
secp521r1 (521-bit)¶

7.1. Additional Recommendations

Implementations SHOULD regularly update their cryptographic libraries to maintain security against evolving threats.¶
Nodes MUST verify the signatures of incoming messages to ensure authenticity.¶
Nonce sizes MUST be sufficient (8 bytes at minimum) to prevent replay attacks.¶
It is RECOMMENDED that nodes securely store their private keys using encryption and protected hardware when possible to prevent unauthorized access.¶

9. Normative References

[RFC2119]: Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC4492]: Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B. Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS)", RFC 4492, DOI 10.17487/RFC4492, May 2006, <https://www.rfc-editor.org/rfc/rfc4492>.
[RFC5639]: Lochter, M. and J. Merkle, "Elliptic Curve Cryptography (ECC) Brainpool Standard Curves and Curve Generation", RFC 5639, DOI 10.17487/RFC5639, March 2010, <https://www.rfc-editor.org/rfc/rfc5639>.
[RFC6979]: Pornin, T., "Deterministic Usage of the Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA)", RFC 6979, DOI 10.17487/RFC6979, August 2013, <https://www.rfc-editor.org/rfc/rfc6979>.