diff --git a/.travis.yml b/.travis.yml
index 01884e66..db8f4cac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,47 +4,58 @@ dist: xenial
 
 matrix:
   include:
-    - os: linux
+    - name: "Linux + GCC + Linting + Metadata"
+      os: linux
       compiler: gcc
       env:
         - MAKETARGET="test-all tidy-all check-format check-metadata check-license-files"
       addons:
         apt:
           packages:
-            - valgrind
             - python3
-            - python3-setuptools
-            - python3-pip
-    - os: linux
+            - python3-yaml
+            - valgrind
+    - name: "Linux + Clang"
+      os: linux
       compiler: clang
       env:
         - MAKETARGET=test-all
       addons:
         apt:
           packages:
-            - valgrind
             - python3
-            - python3-setuptools
-            - python3-pip
-    - os: osx
+            - python3-yaml
+            - valgrind
+    - name: "Run tests on qemu-ppc"
+      os: linux
+      services: docker
+      env:
+        - MAKETARGET="run-functest-all run-testvectors-all run-sanitizer-all run-symbol-namespace-all"
+      script:  # TODO: should we do this in a Dockerfile instead?
+        - docker run --rm --privileged multiarch/qemu-user-static:register --reset
+        - docker run --rm -v `pwd`:`pwd` -w `pwd` "twiggers/debian-sid-powerpc" /bin/bash -c "uname -a &&
+          make ${MAKETARGET}"
+    - name: "MacOS + Clang"
+      os: osx
       osx_image: xcode10.1
       compiler: clang
+      before_install:
+        - pip3 install -r requirements.txt
       env:
         - MAKETARGET=test-all
-    - os: osx
+    - name: "MacOS + GCC8"
+      os: osx
       osx_image: xcode10.1
       compiler: gcc
       addons:
         homebrew:
           packages:
             - gcc@8
+      before_install:
+        - pip3 install -r requirements.txt
       env:
         - MAKETARGET=test-all
 
-before_install:
-  - python3 --version
-  - pip3 install -r requirements.txt
-
 script:
   - make ${MAKETARGET}
 
diff --git a/Makefile b/Makefile
index df4c1ca6..a99e7a90 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,8 @@
 CFLAGS=-Wall -Wextra -Wpedantic -Werror -std=c99 -g $(EXTRAFLAGS)
 
 ALL_SCHEMES=$(filter-out crypto_%.c, $(wildcard crypto_*/*))
+COMMON_FILES = common/fips202.c common/sha2.c
+RANDOM_IMPL = common/randombytes.c
 
 default: help
 
@@ -19,8 +21,9 @@ bin/functest_$(subst /,_,$(SCHEME)): test/$(dir $(SCHEME))functest.c $(wildcard
 		-iquote "./common/" \
 		-iquote "$(SCHEME)/clean/" \
 		-o bin/functest_$(subst /,_,$(SCHEME)) \
-		common/*.c \
 		$(SCHEME)/clean/*.c \
+		$(COMMON_FILES) \
+		$(RANDOM_IMPL) \
 		$<
 
 .PHONY: functest
@@ -45,7 +48,8 @@ bin/sanitizer_$(subst /,_,$(SCHEME)): test/$(dir $(SCHEME))functest.c $(wildcard
 		-iquote "./common/" \
 		-iquote "$(SCHEME)/clean/" \
 		-o bin/sanitizer_$(subst /,_,$(SCHEME)) \
-		common/*.c \
+		$(COMMON_FILES) \
+		$(RANDOM_IMPL) \
 		$(SCHEME)/clean/*.c \
 		$<
 
@@ -59,7 +63,8 @@ bin/testvectors_$(subst /,_,$(SCHEME)): test/$(dir $(SCHEME))testvectors.c $(wil
 		-iquote "./common/" \
 		-iquote "$(SCHEME)/clean/" \
 		-o bin/testvectors_$(subst /,_,$(SCHEME)) \
-		common/*.c \
+		$(COMMON_FILES) \
+		common/notrandombytes.c \
 		$(SCHEME)/clean/*.c \
 		$<
 
diff --git a/README.md b/README.md
index 2abd1e0c..3e28d509 100644
--- a/README.md
+++ b/README.md
@@ -4,9 +4,9 @@
 [![Build status](https://ci.appveyor.com/api/projects/status/186ky7yb9mlqj3io?svg=true)](https://ci.appveyor.com/project/PQClean/pqclean)
 
 **PQClean**, in short, is an effort to collect **clean** implementations of the post-quantum
-schemes that are in the 
+schemes that are in the
 [NIST post-quantum project](https://csrc.nist.gov/projects/post-quantum-cryptography).
-The goal of PQClean is to provide *standalone implementations* that 
+The goal of PQClean is to provide *standalone implementations* that
 
 * can easily be integrated into libraries such as [liboqs](https://openquantumsafe.org/#liboqs) or [libpqcrypto](https://libpqcrypto.org/);
 * can efficiently upstream into higher-level protocol integration efforts such as [Open Quantum Safe](https://openquantumsafe.org/#integrations);
@@ -23,7 +23,7 @@ What PQClean is **not** aiming for is
 * including integration into higher-level applications or protocols.
 
 As a first main target, we are collecting C implementations that fulfill the requirements
-listed below. 
+listed below.
 
 ## Requirements on C implementations that are automatically checked
 
@@ -77,7 +77,7 @@ _The checking of items on this list is still being developed. Checked items shou
 
 ## Clean C implementations currently in PQClean
 
-Currently, the continuous-integration and testing environment of PQClean is still work in progress 
+Currently, the continuous-integration and testing environment of PQClean is still work in progress
 and as a consequence PQClean does not yet have many implementations.
 
 <!--
@@ -94,7 +94,7 @@ and as a consequence PQClean does not yet have many implementations.
 
 ## API used by PQClean
 
-PQClean is essentially using the same API as required for the NIST reference implementations, 
+PQClean is essentially using the same API as required for the NIST reference implementations,
 which is also used by SUPERCOP and by libpqcrypto. The only two differences to that API are
 the following:
 * All lengths are passed as type `size_t` instead of `unsigned long long`; and
@@ -121,7 +121,7 @@ Each implementation directory in PQClean (e.g., crypto\_kem/kyber768\clean) can
 
 Regarding #2, adding the files to your project's build system, each implementation in PQClean is accompanied by example two makefiles that show how one could build the files for that implementation:
 
-- The file `GNUmakefile` which can be used with GNU Make.
+- The file `Makefile` which can be used with GNU Make, BSD Make, and possibly others.
 - The file `Makefile.Microsoft_nmake` which can be used with Visual Studio's nmake.
 
 ## License
diff --git a/common/notrandombytes.c b/common/notrandombytes.c
index 43f16e57..bd6dffdb 100644
--- a/common/notrandombytes.c
+++ b/common/notrandombytes.c
@@ -56,7 +56,7 @@ static void surf(void) {
     }
 }
 
-void randombytes(uint8_t *x, uint64_t xlen) {
+int randombytes(uint8_t *buf, size_t xlen) {
     while (xlen > 0) {
         if (!outleft) {
             if (!++in[0]) {
@@ -69,8 +69,9 @@ void randombytes(uint8_t *x, uint64_t xlen) {
             surf();
             outleft = 8;
         }
-        *x = out[--outleft];
-        ++x;
+        *buf = out[--outleft];
+        ++buf;
         --xlen;
     }
+    return 0;
 }
diff --git a/common/randombytes.c b/common/randombytes.c
new file mode 100644
index 00000000..fac65577
--- /dev/null
+++ b/common/randombytes.c
@@ -0,0 +1,323 @@
+/*
+The MIT License
+
+Copyright (c) 2017 Daan Sprenkels <hello@dsprenkels.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+// In the case that are compiling on linux, we need to define _GNU_SOURCE
+// *before* randombytes.h is included. Otherwise SYS_getrandom will not be
+// declared.
+#if defined(__linux__)
+# define _GNU_SOURCE
+#endif /* defined(__linux__) */
+
+#include "randombytes.h"
+
+#if defined(_WIN32)
+/* Windows */
+# include <windows.h>
+# include <wincrypt.h> /* CryptAcquireContext, CryptGenRandom */
+#endif /* defined(_WIN32) */
+
+
+#if defined(__linux__)
+/* Linux */
+// We would need to include <linux/random.h>, but not every target has access
+// to the linux headers. We only need RNDGETENTCNT, so we instead inline it.
+// RNDGETENTCNT is originally defined in `include/uapi/linux/random.h` in the
+// linux repo.
+# define RNDGETENTCNT 0x80045200
+
+# include <assert.h>
+# include <errno.h>
+# include <fcntl.h>
+# include <poll.h>
+# include <stdint.h>
+# include <stdio.h>
+# include <sys/ioctl.h>
+# include <sys/stat.h>
+# include <sys/syscall.h>
+# include <sys/types.h>
+# include <unistd.h>
+
+// We need SSIZE_MAX as the maximum read len from /dev/urandom
+# if !defined(SSIZE_MAX)
+#  define SSIZE_MAX (SIZE_MAX / 2 - 1)
+# endif /* defined(SSIZE_MAX) */
+
+#endif /* defined(__linux__) */
+
+
+#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
+/* Dragonfly, FreeBSD, NetBSD, OpenBSD (has arc4random) */
+# include <sys/param.h>
+# if defined(BSD)
+#  include <stdlib.h>
+# endif
+#endif
+
+#if defined(__EMSCRIPTEN__)
+# include <assert.h>
+# include <emscripten.h>
+# include <errno.h>
+# include <stdbool.h>
+#endif /* defined(__EMSCRIPTEN__) */
+
+
+#if defined(_WIN32)
+static int randombytes_win32_randombytes(void* buf, const size_t n)
+{
+	HCRYPTPROV ctx;
+	BOOL tmp;
+
+	tmp = CryptAcquireContext(&ctx, NULL, NULL, PROV_RSA_FULL,
+	                          CRYPT_VERIFYCONTEXT);
+	if (tmp == FALSE) return -1;
+
+	tmp = CryptGenRandom(ctx, n, (BYTE*) buf);
+	if (tmp == FALSE) return -1;
+
+	tmp = CryptReleaseContext(ctx, 0);
+	if (tmp == FALSE) return -1;
+
+	return 0;
+}
+#endif /* defined(_WIN32) */
+
+
+#if defined(__linux__) && defined(SYS_getrandom)
+static int randombytes_linux_randombytes_getrandom(void *buf, size_t n)
+{
+	/* I have thought about using a separate PRF, seeded by getrandom, but
+	 * it turns out that the performance of getrandom is good enough
+	 * (250 MB/s on my laptop).
+	 */
+	size_t offset = 0, chunk;
+	int ret;
+	while (n > 0) {
+		/* getrandom does not allow chunks larger than 33554431 */
+		chunk = n <= 33554431 ? n : 33554431;
+		do {
+			ret = syscall(SYS_getrandom, (char *)buf + offset, chunk, 0);
+		} while (ret == -1 && errno == EINTR);
+                if (ret < 0) {
+                    return ret;
+                }
+                offset += ret;
+		n -= ret;
+	}
+	assert(n == 0);
+	return 0;
+}
+#endif /* defined(__linux__) && defined(SYS_getrandom) */
+
+
+#if defined(__linux__) && !defined(SYS_getrandom)
+static int randombytes_linux_read_entropy_ioctl(int device, int *entropy)
+{
+	return ioctl(device, RNDGETENTCNT, entropy);
+}
+
+static int randombytes_linux_read_entropy_proc(FILE *stream, int *entropy)
+{
+	int retcode;	
+	do {
+		rewind(stream);
+		retcode = fscanf(stream, "%d", entropy);
+	} while (retcode != 1 && errno == EINTR);
+	if (retcode != 1) {
+		return -1;
+	}
+	return 0;
+}
+
+static int randombytes_linux_wait_for_entropy(int device)
+{
+	/* We will block on /dev/random, because any increase in the OS' entropy
+	 * level will unblock the request. I use poll here (as does libsodium),
+	 * because we don't *actually* want to read from the device. */
+	enum { IOCTL, PROC } strategy = IOCTL;
+	const int bits = 128;
+	struct pollfd pfd;
+	int fd;
+	FILE *proc_file;
+	int retcode, retcode_error = 0; // Used as return codes throughout this function
+	int entropy = 0;
+
+	/* If the device has enough entropy already, we will want to return early */
+	retcode = randombytes_linux_read_entropy_ioctl(device, &entropy);
+	if (retcode != 0 && errno == ENOTTY) {
+		/* The ioctl call on /dev/urandom has failed due to a ENOTTY (i.e.
+		 * unsupported action). We will fall back to reading from
+		 * `/proc/sys/kernel/random/entropy_avail`. This is obviously less
+		 * ideal, but at this point it seems we have no better option. */
+		strategy = PROC;
+		// Open the entropy count file
+		proc_file = fopen("/proc/sys/kernel/random/entropy_avail", "r");
+	} else if (retcode != 0) {
+		// Unrecoverable ioctl error
+		return -1;
+	}
+	if (entropy >= bits) {
+		return 0;
+	}
+
+	do {
+		fd = open("/dev/random", O_RDONLY);
+	} while (fd == -1 && errno == EINTR); /* EAGAIN will not occur */
+	if (fd == -1) {
+		/* Unrecoverable IO error */
+		return -1;
+	}
+
+	pfd.fd = fd;
+	pfd.events = POLLIN;
+	for (;;) {
+		retcode = poll(&pfd, 1, -1);
+		if (retcode == -1 && (errno == EINTR || errno == EAGAIN)) {
+			continue;
+		} else if (retcode == 1) {
+			if (strategy == IOCTL) {
+				retcode = randombytes_linux_read_entropy_ioctl(device, &entropy);
+			} else if (strategy == PROC) {
+				retcode = randombytes_linux_read_entropy_proc(proc_file, &entropy);
+			} else {
+				return -1; // Unreachable
+			}
+			
+			if (retcode != 0) {
+				// Unrecoverable I/O error
+				retcode_error = retcode;
+				break;
+			}
+			if (entropy >= bits) {
+				break;
+			}		
+		} else {
+			// Unreachable: poll() should only return -1 or 1
+			retcode_error = -1;
+			break;
+		}
+	}
+	do {
+		retcode = close(fd);
+	} while (retcode == -1 && errno == EINTR);
+	if (strategy == PROC) {
+		do {
+			retcode = fclose(proc_file);
+		} while (retcode == -1 && errno == EINTR);		
+	}
+	if (retcode_error != 0) {
+		return retcode_error;
+	}
+	return retcode;
+}
+
+
+static int randombytes_linux_randombytes_urandom(void *buf, size_t n)
+{
+	int fd;
+	size_t offset = 0, count;
+	ssize_t tmp;
+	do {
+		fd = open("/dev/urandom", O_RDONLY);
+	} while (fd == -1 && errno == EINTR);
+	if (fd == -1) return -1;
+	if (randombytes_linux_wait_for_entropy(fd) == -1) return -1;
+
+	while (n > 0) {
+		count = n <= SSIZE_MAX ? n : SSIZE_MAX;
+		tmp = read(fd, (char *)buf + offset, count);
+		if (tmp == -1 && (errno == EAGAIN || errno == EINTR)) {
+			continue;
+		}
+		if (tmp == -1) return -1; /* Unrecoverable IO error */
+		offset += tmp;
+		n -= tmp;
+	}
+	assert(n == 0);
+	return 0;
+}
+#endif /* defined(__linux__) && !defined(SYS_getrandom) */
+
+
+#if defined(BSD)
+static int randombytes_bsd_randombytes(void *buf, size_t n)
+{
+	arc4random_buf(buf, n);
+	return 0;
+}
+#endif /* defined(BSD) */
+
+
+#if defined(__EMSCRIPTEN__)
+static int randombytes_js_randombytes_nodejs(void *buf, size_t n) {
+	const int ret = EM_ASM_INT({
+		var crypto;
+		try {
+			crypto = require('crypto');
+		} catch (error) {
+			return -2;
+		}
+		try {
+			writeArrayToMemory(crypto.randomBytes($1), $0);
+			return 0;
+		} catch (error) {
+			return -1;
+		}
+	}, buf, n);
+	switch (ret) {
+	case 0:
+		return 0;
+	case -1:
+		errno = EINVAL;
+		return -1;
+	case -2:
+		errno = ENOSYS;
+		return -1;
+	}
+	assert(false); // Unreachable
+}
+#endif /* defined(__EMSCRIPTEN__) */
+
+
+int randombytes(uint8_t *buf, size_t n)
+{
+#if defined(__EMSCRIPTEN__)
+	return randombytes_js_randombytes_nodejs(buf, n);
+#elif defined(__linux__)
+# if defined(SYS_getrandom)
+	/* Use getrandom system call */
+	return randombytes_linux_randombytes_getrandom(buf, n);
+# else
+	/* When we have enough entropy, we can read from /dev/urandom */
+	return randombytes_linux_randombytes_urandom(buf, n);
+# endif
+#elif defined(BSD)
+	/* Use arc4random system call */
+	return randombytes_bsd_randombytes(buf, n);
+#elif defined(_WIN32)
+	/* Use windows API */
+	return randombytes_win32_randombytes(buf, n);
+#else
+# error "randombytes(...) is not supported on this platform"
+#endif
+}
diff --git a/common/randombytes.h b/common/randombytes.h
index f99d033e..4ab2fd5e 100644
--- a/common/randombytes.h
+++ b/common/randombytes.h
@@ -2,6 +2,12 @@
 #define RANDOMBYTES_H
 #include <stdint.h>
 
-void randombytes(uint8_t *x, uint64_t xlen);
+#ifdef _WIN32
+#  include <CRTDEFS.H>
+#else
+#  include <unistd.h>
+#endif
+
+int randombytes(uint8_t *buf, size_t xlen);
 
 #endif
diff --git a/crypto_kem/kyber768/clean/Makefile b/crypto_kem/kyber768/clean/Makefile
new file mode 100644
index 00000000..616dcbf3
--- /dev/null
+++ b/crypto_kem/kyber768/clean/Makefile
@@ -0,0 +1,15 @@
+# This Makefile has been tested with GNU Make and BSD Make
+
+LIB=libkyber768_clean.a
+OBJECTS=cbd.o indcpa.o kem.o kex.o ntt.o poly.o polyvec.o precomp.o reduce.o verify.o
+
+CFLAGS=-Wall -Wextra -Wpedantic -Werror -std=c99 -I../../../common $(EXTRAFLAGS)
+
+all: $(LIB)
+
+$(LIB): $(OBJECTS)
+    $(AR) -r $@ $(OBJECTS)
+
+clean:
+    $(RM) $(OBJECTS)
+    $(RM) $(LIB)
diff --git a/crypto_kem/kyber768/clean/Makefile.Microsoft_nmake b/crypto_kem/kyber768/clean/Makefile.Microsoft_nmake
index c7fa6449..af4b6833 100644
--- a/crypto_kem/kyber768/clean/Makefile.Microsoft_nmake
+++ b/crypto_kem/kyber768/clean/Makefile.Microsoft_nmake
@@ -1,5 +1,7 @@
-LIB=libkyber768_clean.lib
+# This Makefile can be used with Microsoft Visual Studio's nmake using the command:
+#    nmake /f Makefile.Microsoft_nmake
 
+LIB=libkyber768_clean.lib
 OBJECTS=cbd.obj indcpa.obj kem.obj kex.obj ntt.obj poly.obj polyvec.obj precomp.obj reduce.obj verify.obj
 
 CFLAGS=/I ..\..\..\common /W1 /WX # FIXME: ideally would use /W4 instead of /W1, but too many failures in Kyber right now
@@ -7,8 +9,8 @@ CFLAGS=/I ..\..\..\common /W1 /WX # FIXME: ideally would use /W4 instead of /W1,
 all: $(LIB)
 
 $(LIB): $(OBJECTS)
-	LIB.EXE /OUT:$@ $**
+    LIB.EXE /OUT:$@ $**
 
 clean:
-	DEL $(OBJECTS)
-	DEL $(LIB)
+    DEL $(OBJECTS)
+    DEL $(LIB)