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diff --git a/content/posts/2023-10-07-c11-fips203ipd.md b/content/posts/2023-10-07-c11-fips203ipd.md index 1ba1dc8..aa45ca1 100644 --- a/content/posts/2023-10-07-c11-fips203ipd.md +++ b/content/posts/2023-10-07-c11-fips203ipd.md @@ -1,23 +1,23 @@ --- slug: C11 Implementation of FIPS 203 IPD -title: "C11 FIPS 203" +title: "C11 FIPS 203 IPD" date: "2023-10-07T12:19:48-04:00" --- -I created a [C11][] implementation of the KEM512, KEM768, and KEM1024 -parameter sets from the [FIPS 203 initial public draft +For fun and also to provide feedback during the draft phase, I created a +[C11][] implementation of the [FIPS 203 initial public draft (IPD)][fips203ipd]. -[FIPS 203][fips203ipd] is (or will be) [NIST's][nist] standardized -version of [Kyber][], a post-quantum [key encapsulation mechanism -(KEM)][kem]. +[FIPS 203][fips203ipd] is a slightly modified version of [Kyber][], and +will (eventually) become [NIST's][nist] standarized post-quantum [key +encapsulation mechanism (KEM)][kem]. ### Features * Full implementation of all three parameter sets from the [FIPS 203 - initial public draft][fips203ipd] -* [C11][], no external dependencies -* Test suite w/ common sanitizers enabled (`make test`) -* API documentation (`fips203ipd.h`) + initial public draft][fips203ipd]. +* [C11][], no external dependencies (other than the standard library). +* Test suite w/ common sanitizers enabled (`make test`). +* Doxygen-friendly API documentation (`fips203ipd.h`). * short example application (`examples/0-hello-kem/`). [Git Repository][github] @@ -31,10 +31,20 @@ correctly][djb-kyber], by [Dan Bernstein (djb)][djb]. ## Example -This example application is also included in the [git -repository][github] as `examples/0-hello-kem/`. +Below is the source code and output of a minimal [C11][] example +application which demonstrates the following: -### Source +1. Alice generates a random KEM512 encapsulation/decapsulation key pair. +2. Alice sends the encapsulation key to Bob. +3. Bob uses the encapsulation key sent by Alice to encapsulate a random shared secret as ciphertext. +4. Bob sends the ciphertext to Alice. +5. Alice uses the decapsulation key to decapsulate the shared secret from the ciphertext sent by Bob. +6. Application verifies that the shared secrets from steps #3 and #5 match. + +This example is also included in the [git repository][github] as +`examples/0-hello-kem/`. + +### Example Source Code ```c // @@ -68,6 +78,7 @@ int main(void) { // alice: generate encapsulation/decapsulation key pair fips203ipd_kem512_keygen(ek, dk, keygen_seed); } + fputs("alice: generated encapsulation key `ek` and decapsulation key `dk`:\n", stdout); printf("alice: ek (%d bytes) = ", FIPS203IPD_KEM512_EK_SIZE); hex_write(stdout, ek, sizeof(ek)); @@ -138,11 +149,12 @@ int main(void) { } ``` -### Output +### Example Output Output of `./hello` with longer lines truncated for brevity: ```sh +> ./hello alice: keygen random (64 bytes) = d656012a9eb09aa50e77a205188f0156e98276a584dcc11c2dfef0c06003ca38b233fab93e9f8dd5adec32278c8d091190112285b7389510bd610ec7b23376b2 alice: generated encapsulation key `ek` and decapsulation key `dk`: alice: ek (800 bytes) = af3b0497f6 ... (omitted) ... 31f0f62cbd @@ -160,8 +172,10 @@ alice: a_key (32 bytes) = 32c9eb490db7e8500d9b209d78a9367fd73a967d8d58edff865527 SUCCESS! alice secret `a_key` and bob secret `b_key` match. ``` + -### +**Update (2023-10-10):** Fixed typos, added rationale to intro, and +added a brief explanation to the example section. [c11]: https://en.wikipedia.org/wiki/C11_(C_standard_revision) "ISO/IEC 9899:2011" |