diff options
Diffstat (limited to 'doc/cs/content/4_3_implementation.tex')
| -rw-r--r-- | doc/cs/content/4_3_implementation.tex | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/doc/cs/content/4_3_implementation.tex b/doc/cs/content/4_3_implementation.tex index 07423e4e1..879e69e8f 100644 --- a/doc/cs/content/4_3_implementation.tex +++ b/doc/cs/content/4_3_implementation.tex @@ -94,8 +94,8 @@ The corresponding crypto helper, that talks with the security module, and its te \item \texttt{src/util/test\_helper\_cs.c}: Tests and benchmarks for the \gls{CSBS} crypto helper \end{itemize} % Crypto API offene Punkte: -%Input-Validierung von Punkten und Skalar -% Clamping beschreiben: https://neilmadden.blog/2020/05/28/whats-the-curve25519-clamping-all-about/ +%Input-validation of points and scalars: +% describe clamping: https://neilmadden.blog/2020/05/28/whats-the-curve25519-clamping-all-about/ % Testing: inverse operations, blinded signature test @@ -219,7 +219,7 @@ Tests for deposit are implemented here: \begin{itemize} \item \url{/src/testing/test_exchange_api.c}: Add tests (see "struct TALER\_TESTING\_Command\ spend\_cs[]") that spend \gls{CSBS} coins withdrawn in tests added for withdrawal \item \url{/src/json/json_pack.c}: Implement \gls{CSBS} case in function TALER\_JSON\_pack\_denom\_sig -\end{itemize} +\end{itemize} \section{Fixing a Minor Security Issue in Taler's RSA Blind Signature Protocols} \label{sec:taler-vuln} @@ -230,7 +230,7 @@ The issue was only in the implementation of the current RSA Blind Signature prot \label{sec:taler-vuln-desc} The redesigned \gls{CSBS} protocols already include the denomination key in the nonce check, which fixes this issue (see \ref{sec:withdraw-protocol-schnorr}). -In the case of \gls{RSABS}, the current protocol includes an \gls{idempotence} check by persisting the hash value of the blinded coin $m'$. +In the case of \gls{RSABS}, the current protocol includes an \gls{idempotence} check by persisting the hash value of the blinded coin $m'$. On a withdrawal/refresh the \gls{idempotence} check compares if the hash value of $m'$ was seen in the past and returns the 'old' signature on a match. This could lead to the following scenario: @@ -277,7 +277,7 @@ After discussing this issue with Christian Grothoff, the conclusion was to inclu return GNUNET_OK; case TALER_DENOMINATION_CS: ... - + \end{lstlisting} The issue is fixed by adding a hash of the current denomination key into the calculation of the hash used in the \gls{idempotence} check. @@ -295,7 +295,7 @@ The applied fix can be seen in listing \ref{lst:fixed-idempotence}. { struct GNUNET_HashContext *hash_context; hash_context = GNUNET_CRYPTO_hash_context_start (); - + GNUNET_CRYPTO_hash_context_read (hash_context, &denom_hash->hash, sizeof(denom_hash->hash)); @@ -312,7 +312,7 @@ The applied fix can be seen in listing \ref{lst:fixed-idempotence}. { struct GNUNET_HashContext *hash_context; hash_context = GNUNET_CRYPTO_hash_context_start (); - + GNUNET_CRYPTO_hash_context_read (hash_context, &denom_hash->hash, sizeof(denom_hash->hash)); |