In this conversation, the participants are discussing the security and practicality of using blind signing services in various cryptographic protocols such as MuSig, MuSig2, and FROST. Blind signing is a technique where a signer is unable to see the message they are signing, ensuring privacy and preventing the signer from learning any information about the message. The first statement made is that not having proof of knowledge of each R (which represents the ephemeral keys used in the signing process) does not protect against Wagner's attack. Wagner's attack is a specific type of attack that exploits the use of identical random values during the signing process to extract private keys. The second statement suggests that a generic blind signing service can be used for protocols like MuSig, MuSig2, and FROST without the blind signing service being aware of the specific protocol being used. The participant suggests that adding the MuSig tweak (an additional parameter specific to MuSig) to the key during the blind signing request should be sufficient. They also mention that the server having multiple nonces (random values) like in MuSig2 does not improve the server's security significantly. The participant mentions that the main problem is creating a secure blind Schnorr signing service. Schnorr signatures are a type of digital signature algorithm known for their efficiency and security. They also mention that Jonas referred to some papers that explain how to create a secure blind Schnorr signing service. The conversation includes references to previous messages that discuss the importance of proof of knowledge of the ephemeral keys (r values) used in the signing process to prevent attacks. It is mentioned that proving knowledge of the signing key, also known as proof of possession (PoP), does not prevent attacks such as the Wagner attack or attacks on the nonces or the challenge. Overall, the conversation revolves around the security considerations and practical implementations of blind signing services in various cryptographic protocols. The participants discuss the importance of proof of knowledge, the potential vulnerabilities and attacks, and the need for a secure blind Schnorr signing service.

In this conversation, the participants are discussing the security of blind signing services and the use of various signing protocols. Blind signing is a cryptographic technique that allows a party to sign a message without knowing its content, ensuring privacy and security. The first statement states that the lack of proof of knowledge of each individual "R" does not prevent what is known as Wagner's attack. Wagner's attack is a type of attack that targets the security of cryptographic protocols and can potentially lead to the exposure of private keys. The second statement suggests that a generic blind signing service can be used for protocols such as MuSig, MuSig2, FROST, etc., without the blind signing service having knowledge of those specific protocols. The OP (original poster) suggests that adding the necessary parameters, such as the MuSig tweak or BIP32, to the key during the blind signing request can achieve compatibility with these protocols. This approach eliminates the need for a specialized MuSig2 blind signing service. The discussion then shifts to the topic of multiple nonces in MuSig2. Nonces are random numbers that are used to ensure the uniqueness of cryptographic operations. It is mentioned that having multiple nonces in MuSig2 does not necessarily enhance the security of the server. The focus is then redirected to the creation of a secure blind Schnorr signing service, as mentioned by Jonas, who references papers that discuss methods for achieving this. The conversation continues with Erik stating that one cannot select "R" if it is shipped with a "POP" (proof of possession). This statement implies that the selection of "R" is restricted based on the proof of possession, which can limit the potential for attacks. Tom contributes to the conversation by stating that proof of knowledge of the ephemeral keys (r values) used to generate each "R" can prevent the Wagner attack. Ephemeral keys are temporary cryptographic keys used for specific operations. Proof of knowledge ensures that the participant has the necessary knowledge and control over these keys. In response to Tom's comment, Jonas clarifies that none of the attacks discussed in the conversation so far (including attacks on nonces and the challenge c) can be prevented by simply proving knowledge of the signing key (proof of possession). Proof of possession, also known as PoP, refers to providing evidence that the participant possesses the private key corresponding to the public key being used for signing. Overall, the conversation revolves around the security of blind signing services, the compatibility of different signing protocols, the role of multiple nonces, the selection of "R" values, and the importance of proof of knowledge and possession in protecting against potential attacks.

In this discussion, the topic seems to be about the security of a blind signing service for various cryptographic protocols such as MuSig, MuSig2, and FROST. The first point mentioned is that having no proof of knowledge of each "R" does not prevent Wagner's attack. Wagner's attack is a known attack in cryptography that aims to break the security of a cryptographic algorithm by providing carefully crafted inputs. It is unclear how exactly "R" is related to this attack, as it is not further explained in the given text. The second point discusses the use of a generic blind signing service for performing blinded signing operations. The author suggests that such a service can be used for protocols like MuSig and MuSig2 without the service being aware of the specific protocol being used. It is proposed to include the MuSig tweak, BIP32 (a Bitcoin Improvement Proposal related to hierarchical deterministic wallets), or other relevant keys when making the blind signing request. The addition of these keys allows for the extraction of MuSig2 compatible shares without the need for a specialized MuSig2 blind signing service. The statement emphasizes that the server's security is not enhanced by having multiple nonces, as it would be in MuSig2. The focus shifts to the creation of a secure blind Schnorr signing service, suggesting that it is the main challenge in this context. The author mentions that Jonas has referred to some papers that explain how to achieve this security, but integrating those techniques into a protocol may pose difficulties. The following part of the text includes a quoted email conversation between Erik Aronesty and Tom Trevethan. It seems that they are discussing the importance of the r values (ephemeral keys) in preventing the Wagner attack. Tom suggests that proof of knowledge of the r values used to generate each R can prevent the attack, but it is not further discussed or explained. The email conversation ends there, and there is a mention of an HTML attachment that has been scrubbed, so it is not included in the given text. In conclusion, the discussion revolves around the security aspects and practical implementation challenges of blind signing services for various cryptographic protocols. The text touches upon topics like the Wagner attack, the use of generic blind signing services, and the need for secure blind Schnorr signing services. However, the details and connections between these points are not fully clear or explained in the provided text.

In this message, the author is discussing the topic of blind signing services and their security in the context of cryptographic protocols such as MuSig, MuSig2, and FROST. Blind signing is a cryptographic technique where a signer, who possesses a private key, signs a message without knowledge of the content of the message itself. This is done by using a blinding factor that hides the message during the signing process. The signer only sees the blinded message and signs it, without knowing what the actual message is. The author makes a couple of points in their message. First, they state that the absence of proof of knowledge of each R (a variable used in the signing algorithm) does not prevent an attack known as Wagner's attack. Wagner's attack is a method of exploiting weak randomness in a cryptographic scheme, and in this context, it refers to a specific attack on blind signing protocols. Next, the author suggests that a generic blind signing service can be used for protocols like MuSig, MuSig2, or FROST without the service being aware of the specific protocol being used. They argue that it is not necessary to have a specialized blind signing service specifically designed for a particular protocol. Instead, they propose that the MuSig tweak (an additional step in the signing process to improve security) can be added to the key used in the blind signing request. This would allow compatibility with MuSig or other protocols without requiring a dedicated blind signing service for each protocol. The author also mentions the concept of nonces, which are random numbers used in the signing process to ensure that each signature is unique. They state that having multiple nonces in the server, as is done in MuSig2, does not improve the server's security. It seems the author believes that the main challenge in creating a secure blind schnorr signing service (a type of digital signature algorithm) is to ensure the blind signing process itself is secure. In response to the author's points, another person in the discussion argues that proof of knowledge of the r values (ephemeral keys) used to generate each R can prevent the Wagner attack. This refers to proving that the signer knows the specific values used in the blinding process, adding an additional level of security. Overall, the discussion revolves around the security considerations and practical implementation of blind signing services in different cryptographic protocols. It touches on topics such as random number generation, protocol compatibility, and the challenges of creating a secure blind schnorr signing service.

In this message, the author is discussing the concept of blind signing services and their relation to attacks on cryptographic protocols such as MuSig, MuSig2, and FROST. 1. The author begins by stating that the absence of proof of knowledge of each "R" (which represents an ephemeral key) does not prevent Wagner's attack. Wagner's attack is a type of cryptographic attack that aims to compromise the security of a blind signing service. 2. The author then expresses their opinion that a generic blind signing service is sufficient for performing blinded MuSig, MuSig2, or FROST without the service being aware of it. They argue that there is no need for a specialized blind signing service specifically for MuSig2 because the MuSig tweak and/or BIP32 (a Bitcoin Improvement Proposal) can be added to the key when making the blind signing request. The author mentions that creating a blind Schnorr signing service is the main challenge that needs to be addressed. Overall, the author suggests that the key issue is implementing a secure blind schnorr signing service and integrating the necessary protocols and techniques to achieve this. They mention that Jonas has referred to some papers that explain how to create such a service, but note that integrating these techniques into a practical protocol may be challenging. The message also includes previous comments from other individuals, including Erik Aronesty, Tom Trevethan, and Jonas Nick, who mention related topics such as proof of possession and attacks on nonces and challenges in cryptographic protocols. Please note that the information provided here is based on the content of the message, and specific technical knowledge in the field of cryptography may be required to fully understand the concepts discussed.

This text seems to be a snippet from a discussion among individuals regarding the security and implementation of a blind signing service for cryptographic protocols like MuSig, MuSig2, and FROST. Blind signing is a technique where a user can obtain a cryptographic signature on a message without the signer actually seeing the contents of the message. This can be useful in scenarios where privacy or anonymity is desired. The first statement mentions that lacking proof of knowledge of each value called "R" does not prevent an attack known as "Wagner's attack." This attack refers to a specific vulnerability in the blind signing process where an adversary can manipulate the values involved to gather information about the signer's private key. The second statement argues that a generic blind signing service can be sufficient for implementing protocols like MuSig2 without requiring a specialized blind signing service specifically designed for MuSig2. The writer suggests that it is possible to modify the existing blind signing service by incorporating additional tweaks, such as the MuSig tweak, or even the BIP32 (Bitcoin Improvement Proposal) standard, to make it compatible with MuSig2. They imply that the number of nonces (random values used in cryptographic operations) employed by MuSig2 does not necessarily enhance the security of the server. The writer also mentions that creating a secure blind Schnorr signing service is the main problem to be solved. They refer to Jonas mentioning some papers that provide techniques for achieving this, but they highlight the challenge of practically integrating those tricks into the protocol. The later part of the text includes fragments of additional comments and questions from other individuals in the discussion. These comments touch upon topics like proof of knowledge of certain values, attacks on nonces and challenges, and the limitations of proof of possession (PoP) in preventing these attacks. Overall, this text delves into technical details surrounding blind signing services, cryptographic protocols, and the challenges associated with implementing secure and efficient protocols in practice.

In this conversation, the participants are discussing the security of blind signing services and the potential vulnerabilities in certain signature schemes. 1. The first point made is that the lack of proof of knowledge of each random value "R" does not prevent Wagner's attack. Wagner's attack is a type of attack where an adversary can manipulate the random values used in a signature scheme to reveal the private key. 2. The second point is that a generic blind signing service is sufficient for performing blinded signature schemes like MuSig, MuSig2, FROST, etc., without the blind signing service being aware of the specific scheme being used. The participant suggests that it is possible to add the necessary tweaks (such as MuSig tweaks or BIP32) to the keys used in the blind signing request, thereby making any blind signing service compatible with different signature schemes. The participant also mentions that having multiple nonces in a proper MuSig2 implementation does not enhance the security of the blind signing service. The participant also mentions that the main challenge lies in creating a secure blind Schnorr signing service. Jonas, another participant, refers to some papers that explain how to achieve this. The practical integration of these techniques into the protocol is considered a tricky aspect. Following this conversation, Erik Aronesty adds a comment stating that it is not possible to select the random value "R" if it is shipped with a Proof of Possession (PoP). PoP refers to proving knowledge of the signing key, which is usually used as a security measure. Jonas Nick further explains that none of the attacks discussed in the thread so far can be prevented by proving knowledge of the signing key (PoP). The conversation concludes with information about the Bitcoin development mailing list and a notice that an HTML attachment was scrubbed from the message.

This discussion revolves around the security of blind signing services used in cryptographic protocols like MuSig, MuSig2, and FROST. Blind signing is a technique where a signer signs a message without knowing its content, ensuring privacy. The first statement states that the absence of proof of knowledge about each R (which represents ephemeral keys used in the signing process) does not prevent an attack called Wagner's attack. Wagner's attack is a type of cryptanalysis that aims to exploit vulnerabilities in cryptographic systems. The second statement suggests that a generic blind signing service is sufficient for implementing blinded MuSig, MuSig2, FROST, or any similar protocols without the blind signing service being aware of it. In other words, you can use a blind signing service that is not specifically designed for MuSig2 and still extract MuSig2 compatible shares from it. When making a blind signing request, you can simply add the MuSig tweak (and/or BIP32, which is a hierarchical key derivation scheme) to the key used by the blind signing service. The implication here is that the server providing the blind signing service does not need to have multiple nonces (random values used in cryptographic operations) like MuSig2, as it wouldn't enhance the server's security. The author mentions that the main issue is to create a secure blind schnorr signing service. Schnorr signatures are a type of digital signature scheme widely used in Bitcoin and other cryptocurrencies. Jonas, another participant in the discussion, mentioned that there are papers that explain how to achieve this secure blind schnorr signing service. However, integrating these techniques into the existing protocol might be challenging. Someone mentions that it is not about signing but about the secret values of "r" (ephemeral keys) used in the process. Proof of knowledge of these "r" values, used to generate each "R" value (used in the signing process), can prevent Wagner's attack. Proof of knowledge of a key or value demonstrates that the prover possesses the corresponding secret information. Lastly, the conversation includes mentions of an attack on the nonces (ephemeral keys or random values) and an attack on the challenge "c" (a value used in cryptographic schemes). It is noted that proving knowledge of the signing key (or PoP, Proof of Possession) does not prevent these attacks. Proving knowledge of the signing key usually involves demonstrating that one knows the private key corresponding to a given public key. Overall, the discussion primarily focuses on the security of blind signing services and the challenges associated with implementing them in protocols such as MuSig, MuSig2, and FROST. The participants discuss the potential vulnerabilities and ways to mitigate them, including the need for a secure blind schnorr signing service and the importance of proof of knowledge for certain attacks.

In this conversation, the participants are discussing the security and practicality of using blind signing services in various cryptographic protocols such as MuSig, MuSig2, and FROST. Blind signing is a technique where a signer is unable to see the message they are signing, ensuring privacy and preventing the signer from learning any information about the message. The first statement made is that not having proof of knowledge of each R (which represents the ephemeral keys used in the signing process) does not protect against Wagner's attack. Wagner's attack is a specific type of attack that exploits the use of identical random values during the signing process to extract private keys. The second statement suggests that a generic blind signing service can be used for protocols like MuSig, MuSig2, and FROST without the blind signing service being aware of the specific protocol being used. The participant suggests that adding the MuSig tweak (an additional parameter specific to MuSig) to the key during the blind signing request should be sufficient. They also mention that the server having multiple nonces (random values) like in MuSig2 does not improve the server's security significantly. The participant mentions that the main problem is creating a secure blind Schnorr signing service. Schnorr signatures are a type of digital signature algorithm known for their efficiency and security. They also mention that Jonas referred to some papers that explain how to create a secure blind Schnorr signing service. The conversation includes references to previous messages that discuss the importance of proof of knowledge of the ephemeral keys (r values) used in the signing process to prevent attacks. It is mentioned that proving knowledge of the signing key, also known as proof of possession (PoP), does not prevent attacks such as the Wagner attack or attacks on the nonces or the challenge. Overall, the conversation revolves around the security considerations and practical implementations of blind signing services in various cryptographic protocols. The participants discuss the importance of proof of knowledge, the potential vulnerabilities and attacks, and the need for a secure blind Schnorr signing service.

In this conversation, the participants are discussing the security of blind signing services and the use of various signing protocols. Blind signing is a cryptographic technique that allows a party to sign a message without knowing its content, ensuring privacy and security. The first statement states that the lack of proof of knowledge of each individual "R" does not prevent what is known as Wagner's attack. Wagner's attack is a type of attack that targets the security of cryptographic protocols and can potentially lead to the exposure of private keys. The second statement suggests that a generic blind signing service can be used for protocols such as MuSig, MuSig2, FROST, etc., without the blind signing service having knowledge of those specific protocols. The OP (original poster) suggests that adding the necessary parameters, such as the MuSig tweak or BIP32, to the key during the blind signing request can achieve compatibility with these protocols. This approach eliminates the need for a specialized MuSig2 blind signing service. The discussion then shifts to the topic of multiple nonces in MuSig2. Nonces are random numbers that are used to ensure the uniqueness of cryptographic operations. It is mentioned that having multiple nonces in MuSig2 does not necessarily enhance the security of the server. The focus is then redirected to the creation of a secure blind Schnorr signing service, as mentioned by Jonas, who references papers that discuss methods for achieving this. The conversation continues with Erik stating that one cannot select "R" if it is shipped with a "POP" (proof of possession). This statement implies that the selection of "R" is restricted based on the proof of possession, which can limit the potential for attacks. Tom contributes to the conversation by stating that proof of knowledge of the ephemeral keys (r values) used to generate each "R" can prevent the Wagner attack. Ephemeral keys are temporary cryptographic keys used for specific operations. Proof of knowledge ensures that the participant has the necessary knowledge and control over these keys. In response to Tom's comment, Jonas clarifies that none of the attacks discussed in the conversation so far (including attacks on nonces and the challenge c) can be prevented by simply proving knowledge of the signing key (proof of possession). Proof of possession, also known as PoP, refers to providing evidence that the participant possesses the private key corresponding to the public key being used for signing. Overall, the conversation revolves around the security of blind signing services, the compatibility of different signing protocols, the role of multiple nonces, the selection of "R" values, and the importance of proof of knowledge and possession in protecting against potential attacks.

In this discussion, the topic seems to be about the security of a blind signing service for various cryptographic protocols such as MuSig, MuSig2, and FROST. The first point mentioned is that having no proof of knowledge of each "R" does not prevent Wagner's attack. Wagner's attack is a known attack in cryptography that aims to break the security of a cryptographic algorithm by providing carefully crafted inputs. It is unclear how exactly "R" is related to this attack, as it is not further explained in the given text. The second point discusses the use of a generic blind signing service for performing blinded signing operations. The author suggests that such a service can be used for protocols like MuSig and MuSig2 without the service being aware of the specific protocol being used. It is proposed to include the MuSig tweak, BIP32 (a Bitcoin Improvement Proposal related to hierarchical deterministic wallets), or other relevant keys when making the blind signing request. The addition of these keys allows for the extraction of MuSig2 compatible shares without the need for a specialized MuSig2 blind signing service. The statement emphasizes that the server's security is not enhanced by having multiple nonces, as it would be in MuSig2. The focus shifts to the creation of a secure blind Schnorr signing service, suggesting that it is the main challenge in this context. The author mentions that Jonas has referred to some papers that explain how to achieve this security, but integrating those techniques into a protocol may pose difficulties. The following part of the text includes a quoted email conversation between Erik Aronesty and Tom Trevethan. It seems that they are discussing the importance of the r values (ephemeral keys) in preventing the Wagner attack. Tom suggests that proof of knowledge of the r values used to generate each R can prevent the attack, but it is not further discussed or explained. The email conversation ends there, and there is a mention of an HTML attachment that has been scrubbed, so it is not included in the given text. In conclusion, the discussion revolves around the security aspects and practical implementation challenges of blind signing services for various cryptographic protocols. The text touches upon topics like the Wagner attack, the use of generic blind signing services, and the need for secure blind Schnorr signing services. However, the details and connections between these points are not fully clear or explained in the provided text.

In this message, the author is discussing the topic of blind signing services and their security in the context of cryptographic protocols such as MuSig, MuSig2, and FROST. Blind signing is a cryptographic technique where a signer, who possesses a private key, signs a message without knowledge of the content of the message itself. This is done by using a blinding factor that hides the message during the signing process. The signer only sees the blinded message and signs it, without knowing what the actual message is. The author makes a couple of points in their message. First, they state that the absence of proof of knowledge of each R (a variable used in the signing algorithm) does not prevent an attack known as Wagner's attack. Wagner's attack is a method of exploiting weak randomness in a cryptographic scheme, and in this context, it refers to a specific attack on blind signing protocols. Next, the author suggests that a generic blind signing service can be used for protocols like MuSig, MuSig2, or FROST without the service being aware of the specific protocol being used. They argue that it is not necessary to have a specialized blind signing service specifically designed for a particular protocol. Instead, they propose that the MuSig tweak (an additional step in the signing process to improve security) can be added to the key used in the blind signing request. This would allow compatibility with MuSig or other protocols without requiring a dedicated blind signing service for each protocol. The author also mentions the concept of nonces, which are random numbers used in the signing process to ensure that each signature is unique. They state that having multiple nonces in the server, as is done in MuSig2, does not improve the server's security. It seems the author believes that the main challenge in creating a secure blind schnorr signing service (a type of digital signature algorithm) is to ensure the blind signing process itself is secure. In response to the author's points, another person in the discussion argues that proof of knowledge of the r values (ephemeral keys) used to generate each R can prevent the Wagner attack. This refers to proving that the signer knows the specific values used in the blinding process, adding an additional level of security. Overall, the discussion revolves around the security considerations and practical implementation of blind signing services in different cryptographic protocols. It touches on topics such as random number generation, protocol compatibility, and the challenges of creating a secure blind schnorr signing service.

In this message, the author is discussing the concept of blind signing services and their relation to attacks on cryptographic protocols such as MuSig, MuSig2, and FROST. 1. The author begins by stating that the absence of proof of knowledge of each "R" (which represents an ephemeral key) does not prevent Wagner's attack. Wagner's attack is a type of cryptographic attack that aims to compromise the security of a blind signing service. 2. The author then expresses their opinion that a generic blind signing service is sufficient for performing blinded MuSig, MuSig2, or FROST without the service being aware of it. They argue that there is no need for a specialized blind signing service specifically for MuSig2 because the MuSig tweak and/or BIP32 (a Bitcoin Improvement Proposal) can be added to the key when making the blind signing request. The author mentions that creating a blind Schnorr signing service is the main challenge that needs to be addressed. Overall, the author suggests that the key issue is implementing a secure blind schnorr signing service and integrating the necessary protocols and techniques to achieve this. They mention that Jonas has referred to some papers that explain how to create such a service, but note that integrating these techniques into a practical protocol may be challenging. The message also includes previous comments from other individuals, including Erik Aronesty, Tom Trevethan, and Jonas Nick, who mention related topics such as proof of possession and attacks on nonces and challenges in cryptographic protocols. Please note that the information provided here is based on the content of the message, and specific technical knowledge in the field of cryptography may be required to fully understand the concepts discussed.

This text seems to be a snippet from a discussion among individuals regarding the security and implementation of a blind signing service for cryptographic protocols like MuSig, MuSig2, and FROST. Blind signing is a technique where a user can obtain a cryptographic signature on a message without the signer actually seeing the contents of the message. This can be useful in scenarios where privacy or anonymity is desired. The first statement mentions that lacking proof of knowledge of each value called "R" does not prevent an attack known as "Wagner's attack." This attack refers to a specific vulnerability in the blind signing process where an adversary can manipulate the values involved to gather information about the signer's private key. The second statement argues that a generic blind signing service can be sufficient for implementing protocols like MuSig2 without requiring a specialized blind signing service specifically designed for MuSig2. The writer suggests that it is possible to modify the existing blind signing service by incorporating additional tweaks, such as the MuSig tweak, or even the BIP32 (Bitcoin Improvement Proposal) standard, to make it compatible with MuSig2. They imply that the number of nonces (random values used in cryptographic operations) employed by MuSig2 does not necessarily enhance the security of the server. The writer also mentions that creating a secure blind Schnorr signing service is the main problem to be solved. They refer to Jonas mentioning some papers that provide techniques for achieving this, but they highlight the challenge of practically integrating those tricks into the protocol. The later part of the text includes fragments of additional comments and questions from other individuals in the discussion. These comments touch upon topics like proof of knowledge of certain values, attacks on nonces and challenges, and the limitations of proof of possession (PoP) in preventing these attacks. Overall, this text delves into technical details surrounding blind signing services, cryptographic protocols, and the challenges associated with implementing secure and efficient protocols in practice.

In this conversation, the participants are discussing the security of blind signing services and the potential vulnerabilities in certain signature schemes. 1. The first point made is that the lack of proof of knowledge of each random value "R" does not prevent Wagner's attack. Wagner's attack is a type of attack where an adversary can manipulate the random values used in a signature scheme to reveal the private key. 2. The second point is that a generic blind signing service is sufficient for performing blinded signature schemes like MuSig, MuSig2, FROST, etc., without the blind signing service being aware of the specific scheme being used. The participant suggests that it is possible to add the necessary tweaks (such as MuSig tweaks or BIP32) to the keys used in the blind signing request, thereby making any blind signing service compatible with different signature schemes. The participant also mentions that having multiple nonces in a proper MuSig2 implementation does not enhance the security of the blind signing service. The participant also mentions that the main challenge lies in creating a secure blind Schnorr signing service. Jonas, another participant, refers to some papers that explain how to achieve this. The practical integration of these techniques into the protocol is considered a tricky aspect. Following this conversation, Erik Aronesty adds a comment stating that it is not possible to select the random value "R" if it is shipped with a Proof of Possession (PoP). PoP refers to proving knowledge of the signing key, which is usually used as a security measure. Jonas Nick further explains that none of the attacks discussed in the thread so far can be prevented by proving knowledge of the signing key (PoP). The conversation concludes with information about the Bitcoin development mailing list and a notice that an HTML attachment was scrubbed from the message.

This discussion revolves around the security of blind signing services used in cryptographic protocols like MuSig, MuSig2, and FROST. Blind signing is a technique where a signer signs a message without knowing its content, ensuring privacy. The first statement states that the absence of proof of knowledge about each R (which represents ephemeral keys used in the signing process) does not prevent an attack called Wagner's attack. Wagner's attack is a type of cryptanalysis that aims to exploit vulnerabilities in cryptographic systems. The second statement suggests that a generic blind signing service is sufficient for implementing blinded MuSig, MuSig2, FROST, or any similar protocols without the blind signing service being aware of it. In other words, you can use a blind signing service that is not specifically designed for MuSig2 and still extract MuSig2 compatible shares from it. When making a blind signing request, you can simply add the MuSig tweak (and/or BIP32, which is a hierarchical key derivation scheme) to the key used by the blind signing service. The implication here is that the server providing the blind signing service does not need to have multiple nonces (random values used in cryptographic operations) like MuSig2, as it wouldn't enhance the server's security. The author mentions that the main issue is to create a secure blind schnorr signing service. Schnorr signatures are a type of digital signature scheme widely used in Bitcoin and other cryptocurrencies. Jonas, another participant in the discussion, mentioned that there are papers that explain how to achieve this secure blind schnorr signing service. However, integrating these techniques into the existing protocol might be challenging. Someone mentions that it is not about signing but about the secret values of "r" (ephemeral keys) used in the process. Proof of knowledge of these "r" values, used to generate each "R" value (used in the signing process), can prevent Wagner's attack. Proof of knowledge of a key or value demonstrates that the prover possesses the corresponding secret information. Lastly, the conversation includes mentions of an attack on the nonces (ephemeral keys or random values) and an attack on the challenge "c" (a value used in cryptographic schemes). It is noted that proving knowledge of the signing key (or PoP, Proof of Possession) does not prevent these attacks. Proving knowledge of the signing key usually involves demonstrating that one knows the private key corresponding to a given public key. Overall, the discussion primarily focuses on the security of blind signing services and the challenges associated with implementing them in protocols such as MuSig, MuSig2, and FROST. The participants discuss the potential vulnerabilities and ways to mitigate them, including the need for a secure blind schnorr signing service and the importance of proof of knowledge for certain attacks.

In this conversation, the participants are discussing the security and practicality of using blind signing services in various cryptographic protocols such as MuSig, MuSig2, and FROST. Blind signing is a technique where a signer is unable to see the message they are signing, ensuring privacy and preventing the signer from learning any information about the message. The first statement made is that not having proof of knowledge of each R (which represents the ephemeral keys used in the signing process) does not protect against Wagner's attack. Wagner's attack is a specific type of attack that exploits the use of identical random values during the signing process to extract private keys. The second statement suggests that a generic blind signing service can be used for protocols like MuSig, MuSig2, and FROST without the blind signing service being aware of the specific protocol being used. The participant suggests that adding the MuSig tweak (an additional parameter specific to MuSig) to the key during the blind signing request should be sufficient. They also mention that the server having multiple nonces (random values) like in MuSig2 does not improve the server's security significantly. The participant mentions that the main problem is creating a secure blind Schnorr signing service. Schnorr signatures are a type of digital signature algorithm known for their efficiency and security. They also mention that Jonas referred to some papers that explain how to create a secure blind Schnorr signing service. The conversation includes references to previous messages that discuss the importance of proof of knowledge of the ephemeral keys (r values) used in the signing process to prevent attacks. It is mentioned that proving knowledge of the signing key, also known as proof of possession (PoP), does not prevent attacks such as the Wagner attack or attacks on the nonces or the challenge. Overall, the conversation revolves around the security considerations and practical implementations of blind signing services in various cryptographic protocols. The participants discuss the importance of proof of knowledge, the potential vulnerabilities and attacks, and the need for a secure blind Schnorr signing service.

In this conversation, the participants are discussing the security of blind signing services and the use of various signing protocols. Blind signing is a cryptographic technique that allows a party to sign a message without knowing its content, ensuring privacy and security. The first statement states that the lack of proof of knowledge of each individual "R" does not prevent what is known as Wagner's attack. Wagner's attack is a type of attack that targets the security of cryptographic protocols and can potentially lead to the exposure of private keys. The second statement suggests that a generic blind signing service can be used for protocols such as MuSig, MuSig2, FROST, etc., without the blind signing service having knowledge of those specific protocols. The OP (original poster) suggests that adding the necessary parameters, such as the MuSig tweak or BIP32, to the key during the blind signing request can achieve compatibility with these protocols. This approach eliminates the need for a specialized MuSig2 blind signing service. The discussion then shifts to the topic of multiple nonces in MuSig2. Nonces are random numbers that are used to ensure the uniqueness of cryptographic operations. It is mentioned that having multiple nonces in MuSig2 does not necessarily enhance the security of the server. The focus is then redirected to the creation of a secure blind Schnorr signing service, as mentioned by Jonas, who references papers that discuss methods for achieving this. The conversation continues with Erik stating that one cannot select "R" if it is shipped with a "POP" (proof of possession). This statement implies that the selection of "R" is restricted based on the proof of possession, which can limit the potential for attacks. Tom contributes to the conversation by stating that proof of knowledge of the ephemeral keys (r values) used to generate each "R" can prevent the Wagner attack. Ephemeral keys are temporary cryptographic keys used for specific operations. Proof of knowledge ensures that the participant has the necessary knowledge and control over these keys. In response to Tom's comment, Jonas clarifies that none of the attacks discussed in the conversation so far (including attacks on nonces and the challenge c) can be prevented by simply proving knowledge of the signing key (proof of possession). Proof of possession, also known as PoP, refers to providing evidence that the participant possesses the private key corresponding to the public key being used for signing. Overall, the conversation revolves around the security of blind signing services, the compatibility of different signing protocols, the role of multiple nonces, the selection of "R" values, and the importance of proof of knowledge and possession in protecting against potential attacks.

In this discussion, the topic seems to be about the security of a blind signing service for various cryptographic protocols such as MuSig, MuSig2, and FROST. The first point mentioned is that having no proof of knowledge of each "R" does not prevent Wagner's attack. Wagner's attack is a known attack in cryptography that aims to break the security of a cryptographic algorithm by providing carefully crafted inputs. It is unclear how exactly "R" is related to this attack, as it is not further explained in the given text. The second point discusses the use of a generic blind signing service for performing blinded signing operations. The author suggests that such a service can be used for protocols like MuSig and MuSig2 without the service being aware of the specific protocol being used. It is proposed to include the MuSig tweak, BIP32 (a Bitcoin Improvement Proposal related to hierarchical deterministic wallets), or other relevant keys when making the blind signing request. The addition of these keys allows for the extraction of MuSig2 compatible shares without the need for a specialized MuSig2 blind signing service. The statement emphasizes that the server's security is not enhanced by having multiple nonces, as it would be in MuSig2. The focus shifts to the creation of a secure blind Schnorr signing service, suggesting that it is the main challenge in this context. The author mentions that Jonas has referred to some papers that explain how to achieve this security, but integrating those techniques into a protocol may pose difficulties. The following part of the text includes a quoted email conversation between Erik Aronesty and Tom Trevethan. It seems that they are discussing the importance of the r values (ephemeral keys) in preventing the Wagner attack. Tom suggests that proof of knowledge of the r values used to generate each R can prevent the attack, but it is not further discussed or explained. The email conversation ends there, and there is a mention of an HTML attachment that has been scrubbed, so it is not included in the given text. In conclusion, the discussion revolves around the security aspects and practical implementation challenges of blind signing services for various cryptographic protocols. The text touches upon topics like the Wagner attack, the use of generic blind signing services, and the need for secure blind Schnorr signing services. However, the details and connections between these points are not fully clear or explained in the provided text.

In this message, the author is discussing the topic of blind signing services and their security in the context of cryptographic protocols such as MuSig, MuSig2, and FROST. Blind signing is a cryptographic technique where a signer, who possesses a private key, signs a message without knowledge of the content of the message itself. This is done by using a blinding factor that hides the message during the signing process. The signer only sees the blinded message and signs it, without knowing what the actual message is. The author makes a couple of points in their message. First, they state that the absence of proof of knowledge of each R (a variable used in the signing algorithm) does not prevent an attack known as Wagner's attack. Wagner's attack is a method of exploiting weak randomness in a cryptographic scheme, and in this context, it refers to a specific attack on blind signing protocols. Next, the author suggests that a generic blind signing service can be used for protocols like MuSig, MuSig2, or FROST without the service being aware of the specific protocol being used. They argue that it is not necessary to have a specialized blind signing service specifically designed for a particular protocol. Instead, they propose that the MuSig tweak (an additional step in the signing process to improve security) can be added to the key used in the blind signing request. This would allow compatibility with MuSig or other protocols without requiring a dedicated blind signing service for each protocol. The author also mentions the concept of nonces, which are random numbers used in the signing process to ensure that each signature is unique. They state that having multiple nonces in the server, as is done in MuSig2, does not improve the server's security. It seems the author believes that the main challenge in creating a secure blind schnorr signing service (a type of digital signature algorithm) is to ensure the blind signing process itself is secure. In response to the author's points, another person in the discussion argues that proof of knowledge of the r values (ephemeral keys) used to generate each R can prevent the Wagner attack. This refers to proving that the signer knows the specific values used in the blinding process, adding an additional level of security. Overall, the discussion revolves around the security considerations and practical implementation of blind signing services in different cryptographic protocols. It touches on topics such as random number generation, protocol compatibility, and the challenges of creating a secure blind schnorr signing service.

In this message, the author is discussing the concept of blind signing services and their relation to attacks on cryptographic protocols such as MuSig, MuSig2, and FROST. 1. The author begins by stating that the absence of proof of knowledge of each "R" (which represents an ephemeral key) does not prevent Wagner's attack. Wagner's attack is a type of cryptographic attack that aims to compromise the security of a blind signing service. 2. The author then expresses their opinion that a generic blind signing service is sufficient for performing blinded MuSig, MuSig2, or FROST without the service being aware of it. They argue that there is no need for a specialized blind signing service specifically for MuSig2 because the MuSig tweak and/or BIP32 (a Bitcoin Improvement Proposal) can be added to the key when making the blind signing request. The author mentions that creating a blind Schnorr signing service is the main challenge that needs to be addressed. Overall, the author suggests that the key issue is implementing a secure blind schnorr signing service and integrating the necessary protocols and techniques to achieve this. They mention that Jonas has referred to some papers that explain how to create such a service, but note that integrating these techniques into a practical protocol may be challenging. The message also includes previous comments from other individuals, including Erik Aronesty, Tom Trevethan, and Jonas Nick, who mention related topics such as proof of possession and attacks on nonces and challenges in cryptographic protocols. Please note that the information provided here is based on the content of the message, and specific technical knowledge in the field of cryptography may be required to fully understand the concepts discussed.

This text seems to be a snippet from a discussion among individuals regarding the security and implementation of a blind signing service for cryptographic protocols like MuSig, MuSig2, and FROST. Blind signing is a technique where a user can obtain a cryptographic signature on a message without the signer actually seeing the contents of the message. This can be useful in scenarios where privacy or anonymity is desired. The first statement mentions that lacking proof of knowledge of each value called "R" does not prevent an attack known as "Wagner's attack." This attack refers to a specific vulnerability in the blind signing process where an adversary can manipulate the values involved to gather information about the signer's private key. The second statement argues that a generic blind signing service can be sufficient for implementing protocols like MuSig2 without requiring a specialized blind signing service specifically designed for MuSig2. The writer suggests that it is possible to modify the existing blind signing service by incorporating additional tweaks, such as the MuSig tweak, or even the BIP32 (Bitcoin Improvement Proposal) standard, to make it compatible with MuSig2. They imply that the number of nonces (random values used in cryptographic operations) employed by MuSig2 does not necessarily enhance the security of the server. The writer also mentions that creating a secure blind Schnorr signing service is the main problem to be solved. They refer to Jonas mentioning some papers that provide techniques for achieving this, but they highlight the challenge of practically integrating those tricks into the protocol. The later part of the text includes fragments of additional comments and questions from other individuals in the discussion. These comments touch upon topics like proof of knowledge of certain values, attacks on nonces and challenges, and the limitations of proof of possession (PoP) in preventing these attacks. Overall, this text delves into technical details surrounding blind signing services, cryptographic protocols, and the challenges associated with implementing secure and efficient protocols in practice.

In this conversation, the participants are discussing the security of blind signing services and the potential vulnerabilities in certain signature schemes. 1. The first point made is that the lack of proof of knowledge of each random value "R" does not prevent Wagner's attack. Wagner's attack is a type of attack where an adversary can manipulate the random values used in a signature scheme to reveal the private key. 2. The second point is that a generic blind signing service is sufficient for performing blinded signature schemes like MuSig, MuSig2, FROST, etc., without the blind signing service being aware of the specific scheme being used. The participant suggests that it is possible to add the necessary tweaks (such as MuSig tweaks or BIP32) to the keys used in the blind signing request, thereby making any blind signing service compatible with different signature schemes. The participant also mentions that having multiple nonces in a proper MuSig2 implementation does not enhance the security of the blind signing service. The participant also mentions that the main challenge lies in creating a secure blind Schnorr signing service. Jonas, another participant, refers to some papers that explain how to achieve this. The practical integration of these techniques into the protocol is considered a tricky aspect. Following this conversation, Erik Aronesty adds a comment stating that it is not possible to select the random value "R" if it is shipped with a Proof of Possession (PoP). PoP refers to proving knowledge of the signing key, which is usually used as a security measure. Jonas Nick further explains that none of the attacks discussed in the thread so far can be prevented by proving knowledge of the signing key (PoP). The conversation concludes with information about the Bitcoin development mailing list and a notice that an HTML attachment was scrubbed from the message.

This discussion revolves around the security of blind signing services used in cryptographic protocols like MuSig, MuSig2, and FROST. Blind signing is a technique where a signer signs a message without knowing its content, ensuring privacy. The first statement states that the absence of proof of knowledge about each R (which represents ephemeral keys used in the signing process) does not prevent an attack called Wagner's attack. Wagner's attack is a type of cryptanalysis that aims to exploit vulnerabilities in cryptographic systems. The second statement suggests that a generic blind signing service is sufficient for implementing blinded MuSig, MuSig2, FROST, or any similar protocols without the blind signing service being aware of it. In other words, you can use a blind signing service that is not specifically designed for MuSig2 and still extract MuSig2 compatible shares from it. When making a blind signing request, you can simply add the MuSig tweak (and/or BIP32, which is a hierarchical key derivation scheme) to the key used by the blind signing service. The implication here is that the server providing the blind signing service does not need to have multiple nonces (random values used in cryptographic operations) like MuSig2, as it wouldn't enhance the server's security. The author mentions that the main issue is to create a secure blind schnorr signing service. Schnorr signatures are a type of digital signature scheme widely used in Bitcoin and other cryptocurrencies. Jonas, another participant in the discussion, mentioned that there are papers that explain how to achieve this secure blind schnorr signing service. However, integrating these techniques into the existing protocol might be challenging. Someone mentions that it is not about signing but about the secret values of "r" (ephemeral keys) used in the process. Proof of knowledge of these "r" values, used to generate each "R" value (used in the signing process), can prevent Wagner's attack. Proof of knowledge of a key or value demonstrates that the prover possesses the corresponding secret information. Lastly, the conversation includes mentions of an attack on the nonces (ephemeral keys or random values) and an attack on the challenge "c" (a value used in cryptographic schemes). It is noted that proving knowledge of the signing key (or PoP, Proof of Possession) does not prevent these attacks. Proving knowledge of the signing key usually involves demonstrating that one knows the private key corresponding to a given public key. Overall, the discussion primarily focuses on the security of blind signing services and the challenges associated with implementing them in protocols such as MuSig, MuSig2, and FROST. The participants discuss the potential vulnerabilities and ways to mitigate them, including the need for a secure blind schnorr signing service and the importance of proof of knowledge for certain attacks.