mirror of https://github.com/ethereum/go-ethereum
obscuren
10 years ago
commit
49a739c8d6
@ -0,0 +1,84 @@ |
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package randentropy |
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import ( |
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crand "crypto/rand" |
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"encoding/binary" |
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"github.com/ethereum/go-ethereum/crypto/sha3" |
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"io" |
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"os" |
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"strings" |
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"time" |
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) |
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var Reader io.Reader = &randEntropy{} |
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type randEntropy struct { |
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} |
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func (*randEntropy) Read(bytes []byte) (n int, err error) { |
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readBytes := GetEntropyMixed(len(bytes)) |
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copy(bytes, readBytes) |
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return len(bytes), nil |
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} |
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// TODO: copied from crypto.go , move to sha3 package?
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func Sha3(data []byte) []byte { |
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d := sha3.NewKeccak256() |
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d.Write(data) |
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return d.Sum(nil) |
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} |
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// TODO: verify. this needs to be audited
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// we start with crypt/rand, then XOR in additional entropy from OS
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func GetEntropyMixed(n int) []byte { |
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startTime := time.Now().UnixNano() |
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// for each source, we take SHA3 of the source and use it as seed to math/rand
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// then read bytes from it and XOR them onto the bytes read from crypto/rand
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mainBuff := GetEntropyCSPRNG(n) |
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// 1. OS entropy sources
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startTimeBytes := make([]byte, 32) |
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binary.PutVarint(startTimeBytes, startTime) |
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startTimeHash := Sha3(startTimeBytes) |
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mixBytes(mainBuff, startTimeHash) |
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pid := os.Getpid() |
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pidBytes := make([]byte, 32) |
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binary.PutUvarint(pidBytes, uint64(pid)) |
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pidHash := Sha3(pidBytes) |
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mixBytes(mainBuff, pidHash) |
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osEnv := os.Environ() |
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osEnvBytes := []byte(strings.Join(osEnv, "")) |
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osEnvHash := Sha3(osEnvBytes) |
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mixBytes(mainBuff, osEnvHash) |
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// not all OS have hostname in env variables
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osHostName, err := os.Hostname() |
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if err != nil { |
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osHostNameBytes := []byte(osHostName) |
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osHostNameHash := Sha3(osHostNameBytes) |
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mixBytes(mainBuff, osHostNameHash) |
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} |
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return mainBuff |
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} |
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func GetEntropyCSPRNG(n int) []byte { |
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mainBuff := make([]byte, n) |
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_, err := io.ReadFull(crand.Reader, mainBuff) |
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if err != nil { |
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panic("reading from crypto/rand failed: " + err.Error()) |
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} |
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return mainBuff |
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} |
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func mixBytes(buff []byte, mixBuff []byte) []byte { |
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bytesToMix := len(buff) |
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if bytesToMix > 32 { |
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bytesToMix = 32 |
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} |
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for i := 0; i < bytesToMix; i++ { |
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buff[i] ^= mixBuff[i] |
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} |
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return buff |
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} |
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@ -1,97 +0,0 @@ |
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package secp256k1 |
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import ( |
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crand "crypto/rand" |
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"io" |
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mrand "math/rand" |
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"os" |
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"strings" |
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"time" |
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) |
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/* |
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Note: |
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- On windows cryto/rand uses CrytoGenRandom which uses RC4 which is insecure |
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- Android random number generator is known to be insecure. |
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- Linux uses /dev/urandom , which is thought to be secure and uses entropy pool |
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Therefore the output is salted. |
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*/ |
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//finalizer from MurmerHash3
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func mmh3f(key uint64) uint64 { |
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key ^= key >> 33 |
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key *= 0xff51afd7ed558ccd |
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key ^= key >> 33 |
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key *= 0xc4ceb9fe1a85ec53 |
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key ^= key >> 33 |
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return key |
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} |
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//knuth hash
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func knuth_hash(in []byte) uint64 { |
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var acc uint64 = 3074457345618258791 |
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for i := 0; i < len(in); i++ { |
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acc += uint64(in[i]) |
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acc *= 3074457345618258799 |
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} |
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return acc |
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} |
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var _rand *mrand.Rand |
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func init() { |
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var seed1 uint64 = mmh3f(uint64(time.Now().UnixNano())) |
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var seed2 uint64 = knuth_hash([]byte(strings.Join(os.Environ(), ""))) |
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var seed3 uint64 = mmh3f(uint64(os.Getpid())) |
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_rand = mrand.New(mrand.NewSource(int64(seed1 ^ seed2 ^ seed3))) |
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} |
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func saltByte(n int) []byte { |
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buff := make([]byte, n) |
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for i := 0; i < len(buff); i++ { |
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var v uint64 = uint64(_rand.Int63()) |
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var b byte |
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for j := 0; j < 8; j++ { |
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b ^= byte(v & 0xff) |
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v = v >> 8 |
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} |
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buff[i] = b |
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} |
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return buff |
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} |
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//On Unix-like systems, Reader reads from /dev/urandom.
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//On Windows systems, Reader uses the CryptGenRandom API.
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//use entropy pool etc and cryptographic random number generator
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//mix in time
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//mix in mix in cpu cycle count
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func RandByte(n int) []byte { |
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buff := make([]byte, n) |
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ret, err := io.ReadFull(crand.Reader, buff) |
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if len(buff) != ret || err != nil { |
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return nil |
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} |
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buff2 := saltByte(n) |
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for i := 0; i < n; i++ { |
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buff[i] ^= buff2[2] |
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} |
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return buff |
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} |
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/* |
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On Unix-like systems, Reader reads from /dev/urandom. |
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On Windows systems, Reader uses the CryptGenRandom API. |
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*/ |
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func RandByteWeakCrypto(n int) []byte { |
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buff := make([]byte, n) |
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ret, err := io.ReadFull(crand.Reader, buff) |
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if len(buff) != ret || err != nil { |
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return nil |
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} |
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return buff |
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} |
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