Problems with the IBC v2 Spec

Oct 13, 2025 by wbrum.org 122 views

Context

As the Inter-Blockchain Communication (IBC) protocol continues to evolve, it's essential to review and understand the latest specifications. In this article, we'll delve into the IBC v2 spec issues, highlighting the problems that have been identified and their potential impact on the protocol's implementation.

Problems with the IBC v2 Spec

1. Incorrect Packet Type

The Packet type in the IBC v2 spec appears to be incorrect. It contains channel and port IDs that don't match the implementation in ibc-go v10.0.0-rc3. This discrepancy can lead to confusion and potential errors in the implementation of the protocol.

Packet Type Inconsistency

The Packet type in the IBC v2 spec is defined as follows:

Packet = ChannelIdentifier PortIdentifier SequenceIdentifier PacketData

However, the implementation in ibc-go v10.0.0-rc3 defines the Packet type as:

Packet = ChannelIdentifier PortIdentifier SequenceIdentifier PacketData, Header

The addition of the Header field in the ibc-go implementation is not reflected in the IBC v2 spec. This inconsistency can lead to issues when implementing the protocol, as the correct Packet type is not clearly defined.

Reference Implementation

The reference implementation of the IBC protocol in ibc-go v10.0.0-rc3 can be found in the following GitHub repository:

2. Missing Channel Identifier Mapping

Another issue with the IBC v2 spec is the lack of mapping for channel identifiers. The spec mentions channel identifiers but does not provide a clear mapping of how they are used.

Channel Identifier Mapping

The IBC v2 spec defines channel identifiers as follows:

ChannelIdentifier = ChannelID

However, the spec does not provide a clear mapping of how channel identifiers are used in the protocol. This lack of clarity can lead to confusion and potential errors in the implementation of the protocol.

Conclusion

In conclusion, the IBC v2 spec issues identified in this article highlight the need for a clear and consistent definition of the protocol's components. The incorrect Packet type and missing channel identifier mapping can lead to confusion and potential errors in the implementation of the protocol.

Recommendations

To address these issues, we recommend the following:

Review and update the IBC v2 spec to reflect the correct Packet type and channel identifier mapping.
Provide clear and consistent definitions of the protocol's components to avoid confusion and potential errors in the implementation.
Update the reference implementation in ibc-go v10.0.0-rc3 to reflect the corrected Packet type and channel identifier mapping.

By addressing these issues, we can ensure that the IBC protocol is implemented correctly and efficiently, enabling secure and reliable communication between different blockchain networks.

Future Work

Future work on the IBC protocol should focus on addressing the issues identified in this article. This includes:

Reviewing and updating the IBC v2 spec to reflect the correct Packet type and channel identifier mapping.
Providing clear and consistent definitions of the protocol's components.
Updating the reference implementation in ibc-go v10.0.0-rc3 to reflect the corrected Packet type and channel identifier mapping.

By prioritizing these tasks, we can ensure that the IBC protocol is implemented correctly and efficiently, enabling secure and reliable communication between different blockchain networks.

References

https://github.com/cosmos/ibc/blob/7a5a7482482e41be98b3759233b9756e373d732d/spec/eureka/README.md?plain=1#L141-L151
https://github.com/cosmos/ibc-go/blob/e9522265bf0b4f5fd514ed25c519cfa2970138de/modules/core/04-channel/v2/types/packet.pb.go#L62-L76
IBC v2 Spec Issues: A Q&A Article =====================================

Frequently Asked Questions

Q: What are the IBC v2 spec issues?

A: The IBC v2 spec issues include the incorrect Packet type and missing channel identifier mapping. These issues can lead to confusion and potential errors in the implementation of the protocol.

Q: What is the correct Packet type?

A: The correct Packet type is defined in the ibc-go v10.0.0-rc3 implementation as:

Packet = ChannelIdentifier PortIdentifier SequenceIdentifier PacketData, Header

Q: Why is the Packet type inconsistent in the IBC v2 spec?

A: The Packet type in the IBC v2 spec is inconsistent because it does not reflect the correct implementation in ibc-go v10.0.0-rc3. This inconsistency can lead to issues when implementing the protocol.

Q: What is the purpose of channel identifiers in the IBC protocol?

A: Channel identifiers are used to identify channels in the IBC protocol. They are essential for secure and reliable communication between different blockchain networks.

Q: Why is the channel identifier mapping missing in the IBC v2 spec?

A: The channel identifier mapping is missing in the IBC v2 spec because it does not provide a clear definition of how channel identifiers are used in the protocol. This lack of clarity can lead to confusion and potential errors in the implementation of the protocol.

Q: How can the IBC v2 spec issues be addressed?

A: The IBC v2 spec issues can be addressed by reviewing and updating the spec to reflect the correct Packet type and channel identifier mapping. Additionally, providing clear and consistent definitions of the protocol's components can help avoid confusion and potential errors in the implementation.

Q: What is the impact of the IBC v2 spec issues on the implementation of the protocol?

A: The IBC v2 spec issues can lead to confusion and potential errors in the implementation of the protocol. This can result in security vulnerabilities, reliability issues, and other problems that can affect the overall performance of the protocol.

Q: How can developers ensure that they are implementing the IBC protocol correctly?

A: Developers can ensure that they are implementing the IBC protocol correctly by:

Reviewing the IBC v2 spec and understanding the correct Packet type and channel identifier mapping.
Using the reference implementation in ibc-go v10.0.0-rc3 as a guide.
Providing clear and consistent definitions of the protocol's components.
Testing the implementation thoroughly to ensure that it is secure and reliable.

Q: What is the future of the IBC protocol?

A: The future of the IBC protocol is promising, with ongoing development and improvement of the protocol. Addressing the IBC v2 spec issues and providing clear and consistent definitions of the protocol's components can help ensure that the protocol is implemented correctly and efficiently.

Q: How can the IBC community contribute to the development of the protocol?

A: The IBC community can contribute to the development of the protocol by:

Reviewing and providing feedback on the IBC v2 spec.
Participating in discussions and debates about the protocol's design and implementation.
Contributing to the development of the reference implementation in ibc-go v10.0.0-rc3.
Testing and providing feedback on the implementation of the protocol.

By addressing the IBC v2 spec issues and providing clear and consistent definitions of the protocol's components, we can ensure that the IBC protocol is implemented correctly and efficiently, enabling secure and reliable communication between different blockchain networks.