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Diffstat (limited to 'security/nss/lib/freebl/verified/specs/Spec.Poly1305.fst')
-rw-r--r-- | security/nss/lib/freebl/verified/specs/Spec.Poly1305.fst | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/verified/specs/Spec.Poly1305.fst b/security/nss/lib/freebl/verified/specs/Spec.Poly1305.fst new file mode 100644 index 000000000..f9d8a4cb2 --- /dev/null +++ b/security/nss/lib/freebl/verified/specs/Spec.Poly1305.fst @@ -0,0 +1,107 @@ +/* Copyright 2016-2017 INRIA and Microsoft Corporation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +module Spec.Poly1305 + +module ST = FStar.HyperStack.ST + +open FStar.Math.Lib +open FStar.Mul +open FStar.Seq +open FStar.UInt8 +open FStar.Endianness +open Spec.Poly1305.Lemmas + +#set-options "--initial_fuel 0 --max_fuel 0 --initial_ifuel 0 --max_ifuel 0" + +(* Field types and parameters *) +let prime = pow2 130 - 5 +type elem = e:int{e >= 0 /\ e < prime} +let fadd (e1:elem) (e2:elem) = (e1 + e2) % prime +let fmul (e1:elem) (e2:elem) = (e1 * e2) % prime +let zero : elem = 0 +let one : elem = 1 +let op_Plus_At = fadd +let op_Star_At = fmul +(* Type aliases *) +let op_Amp_Bar = UInt.logand #128 +type word = w:bytes{length w <= 16} +type word_16 = w:bytes{length w = 16} +type tag = word_16 +type key = lbytes 32 +type text = seq word + +(* Specification code *) +let encode (w:word) = + (pow2 (8 * length w)) `fadd` (little_endian w) + +let rec poly (txt:text) (r:e:elem) : Tot elem (decreases (length txt)) = + if length txt = 0 then zero + else + let a = poly (Seq.tail txt) r in + let n = encode (Seq.head txt) in + (n `fadd` a) `fmul` r + +let encode_r (rb:word_16) = + (little_endian rb) &| 0x0ffffffc0ffffffc0ffffffc0fffffff + +let finish (a:elem) (s:word_16) : Tot tag = + let n = (a + little_endian s) % pow2 128 in + little_bytes 16ul n + +let rec encode_bytes (txt:bytes) : Tot text (decreases (length txt)) = + if length txt = 0 then createEmpty + else + let w, txt = split txt (min (length txt) 16) in + append_last (encode_bytes txt) w + +let poly1305 (msg:bytes) (k:key) : Tot tag = + let text = encode_bytes msg in + let r = encode_r (slice k 0 16) in + let s = slice k 16 32 in + finish (poly text r) s + + +(* ********************* *) +(* RFC 7539 Test Vectors *) +(* ********************* *) + +#reset-options "--initial_fuel 0 --max_fuel 0 --z3rlimit 20" + +unfold let msg = [ + 0x43uy; 0x72uy; 0x79uy; 0x70uy; 0x74uy; 0x6fuy; 0x67uy; 0x72uy; + 0x61uy; 0x70uy; 0x68uy; 0x69uy; 0x63uy; 0x20uy; 0x46uy; 0x6fuy; + 0x72uy; 0x75uy; 0x6duy; 0x20uy; 0x52uy; 0x65uy; 0x73uy; 0x65uy; + 0x61uy; 0x72uy; 0x63uy; 0x68uy; 0x20uy; 0x47uy; 0x72uy; 0x6fuy; + 0x75uy; 0x70uy ] + +unfold let k = [ + 0x85uy; 0xd6uy; 0xbeuy; 0x78uy; 0x57uy; 0x55uy; 0x6duy; 0x33uy; + 0x7fuy; 0x44uy; 0x52uy; 0xfeuy; 0x42uy; 0xd5uy; 0x06uy; 0xa8uy; + 0x01uy; 0x03uy; 0x80uy; 0x8auy; 0xfbuy; 0x0duy; 0xb2uy; 0xfduy; + 0x4auy; 0xbfuy; 0xf6uy; 0xafuy; 0x41uy; 0x49uy; 0xf5uy; 0x1buy ] + +unfold let expected = [ + 0xa8uy; 0x06uy; 0x1duy; 0xc1uy; 0x30uy; 0x51uy; 0x36uy; 0xc6uy; + 0xc2uy; 0x2buy; 0x8buy; 0xafuy; 0x0cuy; 0x01uy; 0x27uy; 0xa9uy ] + +let test () : Tot bool = + assert_norm(List.Tot.length msg = 34); + assert_norm(List.Tot.length k = 32); + assert_norm(List.Tot.length expected = 16); + let msg = createL msg in + let k = createL k in + let expected = createL expected in + poly1305 msg k = expected |