diff --git a/src/aead.rs b/src/aead.rs
index b9aa4c98..ea051c57 100644
--- a/src/aead.rs
+++ b/src/aead.rs
@@ -81,8 +81,11 @@ use crate::{
 	errors::UnknownCryptoError,
 	hazardous::{
 		aead,
-		constants::{POLY1305_BLOCKSIZE, XCHACHA_NONCESIZE},
-		stream::{chacha20, xchacha20::Nonce},
+		mac::poly1305::POLY1305_OUTSIZE,
+		stream::{
+			chacha20,
+			xchacha20::{Nonce, XCHACHA_NONCESIZE},
+		},
 	},
 };
 
@@ -95,7 +98,7 @@ pub fn seal(secret_key: &SecretKey, plaintext: &[u8]) -> Result<Vec<u8>, Unknown
 
 	let nonce = Nonce::generate();
 
-	let mut dst_out = vec![0u8; plaintext.len() + (XCHACHA_NONCESIZE + POLY1305_BLOCKSIZE)];
+	let mut dst_out = vec![0u8; plaintext.len() + (XCHACHA_NONCESIZE + POLY1305_OUTSIZE)];
 	dst_out[..XCHACHA_NONCESIZE].copy_from_slice(nonce.as_ref());
 
 	aead::xchacha20poly1305::seal(
@@ -116,12 +119,12 @@ pub fn open(
 	ciphertext_with_tag_and_nonce: &[u8],
 ) -> Result<Vec<u8>, UnknownCryptoError> {
 	// `+ 1` to avoid empty ciphertexts
-	if ciphertext_with_tag_and_nonce.len() < (XCHACHA_NONCESIZE + POLY1305_BLOCKSIZE + 1) {
+	if ciphertext_with_tag_and_nonce.len() < (XCHACHA_NONCESIZE + POLY1305_OUTSIZE + 1) {
 		return Err(UnknownCryptoError);
 	}
 
 	let mut dst_out =
-		vec![0u8; ciphertext_with_tag_and_nonce.len() - (XCHACHA_NONCESIZE + POLY1305_BLOCKSIZE)];
+		vec![0u8; ciphertext_with_tag_and_nonce.len() - (XCHACHA_NONCESIZE + POLY1305_OUTSIZE)];
 
 	aead::xchacha20poly1305::open(
 		&chacha20::SecretKey::from_slice(secret_key.unprotected_as_bytes())?,
diff --git a/src/hazardous/aead/chacha20poly1305.rs b/src/hazardous/aead/chacha20poly1305.rs
index 8ecd48e6..ba00b72f 100644
--- a/src/hazardous/aead/chacha20poly1305.rs
+++ b/src/hazardous/aead/chacha20poly1305.rs
@@ -101,8 +101,7 @@ pub use crate::hazardous::stream::chacha20::{Nonce, SecretKey};
 use crate::{
 	errors::UnknownCryptoError,
 	hazardous::{
-		constants::{POLY1305_KEYSIZE, POLY1305_OUTSIZE},
-		mac::poly1305::{self, OneTimeKey},
+		mac::poly1305::{self, OneTimeKey, POLY1305_KEYSIZE, POLY1305_OUTSIZE},
 		stream::chacha20,
 	},
 	util,
@@ -656,7 +655,7 @@ mod private {
 
 	mod test_poly1305_key_gen {
 		use super::*;
-		use crate::hazardous::constants::{CHACHA_KEYSIZE, IETF_CHACHA_NONCESIZE};
+		use crate::hazardous::stream::chacha20::{CHACHA_KEYSIZE, IETF_CHACHA_NONCESIZE};
 
 		#[test]
 		fn test_key_lengths() {
diff --git a/src/hazardous/aead/xchacha20poly1305.rs b/src/hazardous/aead/xchacha20poly1305.rs
index ab965c3e..78aa8d8c 100644
--- a/src/hazardous/aead/xchacha20poly1305.rs
+++ b/src/hazardous/aead/xchacha20poly1305.rs
@@ -94,8 +94,7 @@ use crate::{
 	errors::UnknownCryptoError,
 	hazardous::{
 		aead::chacha20poly1305,
-		constants::IETF_CHACHA_NONCESIZE,
-		stream::chacha20::{self, Nonce as IETFNonce},
+		stream::chacha20::{self, Nonce as IETFNonce, IETF_CHACHA_NONCESIZE},
 	},
 };
 
@@ -159,7 +158,7 @@ pub fn open(
 #[cfg(test)]
 mod public {
 	use super::*;
-	use crate::hazardous::constants::POLY1305_OUTSIZE;
+	use crate::hazardous::mac::poly1305::POLY1305_OUTSIZE;
 	// One function tested per submodule.
 
 	mod test_seal {
diff --git a/src/hazardous/constants.rs b/src/hazardous/constants.rs
deleted file mode 100644
index 61d844d7..00000000
--- a/src/hazardous/constants.rs
+++ /dev/null
@@ -1,60 +0,0 @@
-// MIT License
-
-// Copyright (c) 2018-2019 The orion Developers
-
-// 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.
-
-/// The blocksize for the hash function SHA512.
-pub const SHA512_BLOCKSIZE: usize = 128;
-/// The output size for the hash function SHA512.
-pub const SHA512_OUTSIZE: usize = 64;
-/// The blocksize which ChaCha20 operates on.
-pub const CHACHA_BLOCKSIZE: usize = 64;
-/// The key size for ChaCha20.
-pub const CHACHA_KEYSIZE: usize = 32;
-/// The size of the subkey that HChaCha20 returns.
-pub const HCHACHA_OUTSIZE: usize = 32;
-/// The nonce size for IETF ChaCha20.
-pub const IETF_CHACHA_NONCESIZE: usize = 12;
-/// The nonce size for HChaCha20.
-pub const HCHACHA_NONCESIZE: usize = 16;
-/// The nonce size for XChaCha20.
-pub const XCHACHA_NONCESIZE: usize = 24;
-/// The blocksize which Poly1305 operates on.
-pub const POLY1305_BLOCKSIZE: usize = 16;
-/// The output size for Poly1305.
-pub const POLY1305_OUTSIZE: usize = 16;
-/// The key size for Poly1305.
-pub const POLY1305_KEYSIZE: usize = 32;
-/// The blocksize for the hash function BLAKE2b.
-pub const BLAKE2B_BLOCKSIZE: usize = 128;
-/// The key size for the hash function BLAKE2b when used in keyed mode.
-pub const BLAKE2B_KEYSIZE: usize = 64;
-/// The output size for the hash function BLAKE2b.
-pub const BLAKE2B_OUTSIZE: usize = 64;
-
-/// Type for an array of length `SHA512_BLOCKSIZE`.
-pub type BlocksizeArray = [u8; SHA512_BLOCKSIZE];
-/// Type for an array of length `SHA512_OUTSIZE`.
-pub type HLenArray = [u8; SHA512_OUTSIZE];
-/// Type for a ChaCha state represented as an array of 16 32-bit unsigned
-/// integers.
-pub type ChaChaState = [u32; 16];
-/// Type for a Poly1305 tag.
-pub type Poly1305Tag = [u8; POLY1305_OUTSIZE];
diff --git a/src/hazardous/hash/blake2b.rs b/src/hazardous/hash/blake2b.rs
index a816441e..367d72ad 100644
--- a/src/hazardous/hash/blake2b.rs
+++ b/src/hazardous/hash/blake2b.rs
@@ -76,9 +76,15 @@
 use crate::{
 	endianness::{load_u64_into_le, store_u64_into_le},
 	errors::UnknownCryptoError,
-	hazardous::constants::{BLAKE2B_BLOCKSIZE, BLAKE2B_KEYSIZE, BLAKE2B_OUTSIZE},
 };
 
+/// The blocksize for the hash function BLAKE2b.
+const BLAKE2B_BLOCKSIZE: usize = 128;
+/// The maximum key size for the hash function BLAKE2b when used in keyed mode.
+const BLAKE2B_KEYSIZE: usize = 64;
+/// The maximum output size for the hash function BLAKE2b.
+const BLAKE2B_OUTSIZE: usize = 64;
+
 construct_secret_key! {
 	/// A type to represent the `SecretKey` that BLAKE2b uses for keyed mode.
 	///
diff --git a/src/hazardous/hash/sha512.rs b/src/hazardous/hash/sha512.rs
index 5af8d1dc..be5cd42b 100644
--- a/src/hazardous/hash/sha512.rs
+++ b/src/hazardous/hash/sha512.rs
@@ -53,9 +53,13 @@
 use crate::{
 	endianness::{load_u64_into_be, store_u64_into_be},
 	errors::UnknownCryptoError,
-	hazardous::constants::{SHA512_BLOCKSIZE, SHA512_OUTSIZE},
 };
 
+/// The blocksize for the hash function SHA512.
+pub const SHA512_BLOCKSIZE: usize = 128;
+/// The output size for the hash function SHA512.
+pub const SHA512_OUTSIZE: usize = 64;
+
 construct_public! {
 	/// A type to represent the `Digest` that SHA512 returns.
 	///
diff --git a/src/hazardous/kdf/hkdf.rs b/src/hazardous/kdf/hkdf.rs
index 8acae15e..e8fed6d8 100644
--- a/src/hazardous/kdf/hkdf.rs
+++ b/src/hazardous/kdf/hkdf.rs
@@ -68,7 +68,7 @@
 use crate::{
 	errors::UnknownCryptoError,
 	hazardous::{
-		constants::SHA512_OUTSIZE,
+		hash::sha512::SHA512_OUTSIZE,
 		mac::hmac::{self, SecretKey},
 	},
 	util,
diff --git a/src/hazardous/kdf/pbkdf2.rs b/src/hazardous/kdf/pbkdf2.rs
index cdc7f892..2ce28cf3 100644
--- a/src/hazardous/kdf/pbkdf2.rs
+++ b/src/hazardous/kdf/pbkdf2.rs
@@ -72,7 +72,7 @@
 use crate::{
 	errors::UnknownCryptoError,
 	hazardous::{
-		constants::{HLenArray, SHA512_BLOCKSIZE, SHA512_OUTSIZE},
+		hash::sha512::{SHA512_BLOCKSIZE, SHA512_OUTSIZE},
 		mac::hmac,
 	},
 	util,
@@ -105,7 +105,7 @@ fn function_f(
 	block_len: usize,
 	hmac: &mut hmac::Hmac,
 ) -> Result<(), UnknownCryptoError> {
-	let mut u_step: HLenArray = [0u8; 64];
+	let mut u_step: [u8; SHA512_OUTSIZE] = [0u8; 64];
 	hmac.update(salt)?;
 	hmac.update(&index.to_be_bytes())?;
 
diff --git a/src/hazardous/mac/hmac.rs b/src/hazardous/mac/hmac.rs
index 675af0f5..5ee69e95 100644
--- a/src/hazardous/mac/hmac.rs
+++ b/src/hazardous/mac/hmac.rs
@@ -58,10 +58,7 @@
 
 use crate::{
 	errors::UnknownCryptoError,
-	hazardous::{
-		constants::{BlocksizeArray, SHA512_BLOCKSIZE, SHA512_OUTSIZE},
-		hash::sha512,
-	},
+	hazardous::hash::sha512::{self, SHA512_BLOCKSIZE, SHA512_OUTSIZE},
 };
 use zeroize::Zeroize;
 
@@ -117,8 +114,8 @@ impl Hmac {
 	#[inline]
 	/// Pad `key` with `ipad` and `opad`.
 	fn pad_key_io(&mut self, key: &SecretKey) {
-		let mut ipad: BlocksizeArray = [0x36; SHA512_BLOCKSIZE];
-		let mut opad: BlocksizeArray = [0x5C; SHA512_BLOCKSIZE];
+		let mut ipad = [0x36; SHA512_BLOCKSIZE];
+		let mut opad = [0x5C; SHA512_BLOCKSIZE];
 		// `key` has already been padded with zeroes to a length of SHA512_BLOCKSIZE
 		// in SecretKey::from_slice
 		for (idx, itm) in key.unprotected_as_bytes().iter().enumerate() {
diff --git a/src/hazardous/mac/poly1305.rs b/src/hazardous/mac/poly1305.rs
index 005fecaf..fe5ea8de 100644
--- a/src/hazardous/mac/poly1305.rs
+++ b/src/hazardous/mac/poly1305.rs
@@ -65,9 +65,17 @@ extern crate core;
 use crate::{
 	endianness::{load_u32_le, store_u32_into_le},
 	errors::UnknownCryptoError,
-	hazardous::constants::{Poly1305Tag, POLY1305_BLOCKSIZE, POLY1305_KEYSIZE, POLY1305_OUTSIZE},
 };
 
+/// The blocksize which Poly1305 operates on.
+const POLY1305_BLOCKSIZE: usize = 16;
+/// The output size for Poly1305.
+pub const POLY1305_OUTSIZE: usize = 16;
+/// The key size for Poly1305.
+pub const POLY1305_KEYSIZE: usize = 32;
+/// Type for a Poly1305 tag.
+type Poly1305Tag = [u8; POLY1305_OUTSIZE];
+
 construct_secret_key! {
 	/// A type to represent the `OneTimeKey` that Poly1305 uses for authentication.
 	///
diff --git a/src/hazardous/mod.rs b/src/hazardous/mod.rs
index acd9b5d9..12f9e9e5 100644
--- a/src/hazardous/mod.rs
+++ b/src/hazardous/mod.rs
@@ -39,8 +39,5 @@ pub mod mac;
 /// Function).
 pub mod kdf;
 
-/// Constant values and types.
-pub mod constants;
-
 /// Stream ciphers.
 pub mod stream;
diff --git a/src/hazardous/stream/chacha20.rs b/src/hazardous/stream/chacha20.rs
index f6ddde78..77e6b279 100644
--- a/src/hazardous/stream/chacha20.rs
+++ b/src/hazardous/stream/chacha20.rs
@@ -99,17 +99,23 @@
 use crate::{
 	endianness::{load_u32_into_le, store_u32_into_le},
 	errors::UnknownCryptoError,
-	hazardous::constants::{
-		ChaChaState,
-		CHACHA_BLOCKSIZE,
-		CHACHA_KEYSIZE,
-		HCHACHA_NONCESIZE,
-		HCHACHA_OUTSIZE,
-		IETF_CHACHA_NONCESIZE,
-	},
 };
 use zeroize::Zeroize;
 
+/// The key size for ChaCha20.
+pub const CHACHA_KEYSIZE: usize = 32;
+/// The nonce size for IETF ChaCha20.
+pub const IETF_CHACHA_NONCESIZE: usize = 12;
+/// The blocksize which ChaCha20 operates on.
+const CHACHA_BLOCKSIZE: usize = 64;
+/// The size of the subkey that HChaCha20 returns.
+const HCHACHA_OUTSIZE: usize = 32;
+/// The nonce size for HChaCha20.
+const HCHACHA_NONCESIZE: usize = 16;
+/// Type for a ChaCha state represented as an array of 16 32-bit unsigned
+/// integers.
+type ChaChaState = [u32; 16];
+
 construct_secret_key! {
 	/// A type to represent the `SecretKey` that `chacha20`, `xchacha20`, `chacha20poly1305` and
 	/// `xchacha20poly1305` use.
diff --git a/src/hazardous/stream/xchacha20.rs b/src/hazardous/stream/xchacha20.rs
index a814980c..53c2ee1e 100644
--- a/src/hazardous/stream/xchacha20.rs
+++ b/src/hazardous/stream/xchacha20.rs
@@ -82,12 +82,12 @@
 pub use crate::hazardous::stream::chacha20::SecretKey;
 use crate::{
 	errors::UnknownCryptoError,
-	hazardous::{
-		constants::{IETF_CHACHA_NONCESIZE, XCHACHA_NONCESIZE},
-		stream::chacha20::{self, Nonce as IETFNonce},
-	},
+	hazardous::stream::chacha20::{self, Nonce as IETFNonce, IETF_CHACHA_NONCESIZE},
 };
 
+/// The nonce size for XChaCha20.
+pub const XCHACHA_NONCESIZE: usize = 24;
+
 construct_public! {
 	/// A type that represents a `Nonce` that XChaCha20 and XChaCha20Poly1305 use.
 	///
diff --git a/src/typedefs.rs b/src/typedefs.rs
index a48c43d9..a9270645 100644
--- a/src/typedefs.rs
+++ b/src/typedefs.rs
@@ -566,8 +566,7 @@ macro_rules! construct_hmac_key {
             #[must_use]
             /// Make an object from a given byte slice.
             pub fn from_slice(slice: &[u8]) -> Result<$name, UnknownCryptoError> {
-                use crate::hazardous::hash::sha512;
-                use crate::hazardous::constants::SHA512_OUTSIZE;
+                use crate::hazardous::hash::sha512::{self, SHA512_OUTSIZE};
 
                 let mut secret_key = [0u8; $size];
 
diff --git a/tests/aead/mod.rs b/tests/aead/mod.rs
index e93d7f90..9f021f66 100644
--- a/tests/aead/mod.rs
+++ b/tests/aead/mod.rs
@@ -12,7 +12,10 @@ use self::{
 	},
 	orion::{
 		errors::UnknownCryptoError,
-		hazardous::{aead, constants},
+		hazardous::{
+			aead,
+			stream::{chacha20::IETF_CHACHA_NONCESIZE, xchacha20::XCHACHA_NONCESIZE},
+		},
 	},
 };
 
@@ -44,7 +47,7 @@ fn aead_test_runner(
 	}
 
 	// Determine variant based on NONCE size
-	if nonce.len() == constants::IETF_CHACHA_NONCESIZE {
+	if nonce.len() == IETF_CHACHA_NONCESIZE {
 		aead::chacha20poly1305::seal(
 			&SecretKey::from_slice(&key).unwrap(),
 			&chacha20poly1305::Nonce::from_slice(&nonce).unwrap(),
@@ -67,7 +70,7 @@ fn aead_test_runner(
 		assert!(dst_pt_out[..].as_ref() == input);
 
 		Ok(())
-	} else if nonce.len() == constants::XCHACHA_NONCESIZE {
+	} else if nonce.len() == XCHACHA_NONCESIZE {
 		aead::xchacha20poly1305::seal(
 			&SecretKey::from_slice(&key).unwrap(),
 			&xchacha20poly1305::Nonce::from_slice(&nonce).unwrap(),
diff --git a/tests/stream/mod.rs b/tests/stream/mod.rs
index bf2b4677..3709e437 100644
--- a/tests/stream/mod.rs
+++ b/tests/stream/mod.rs
@@ -9,9 +9,9 @@ extern crate orion;
 use self::{
 	chacha20::SecretKey,
 	hex::decode,
-	orion::hazardous::{
-		constants,
-		stream::{chacha20, xchacha20},
+	orion::hazardous::stream::{
+		chacha20::{self, IETF_CHACHA_NONCESIZE},
+		xchacha20::{self, XCHACHA_NONCESIZE},
 	},
 };
 
@@ -26,7 +26,7 @@ pub fn chacha_test_runner(
 	let original_ct = ct.to_vec();
 
 	// Selecting variant based on nonce size
-	if nonce.len() == constants::IETF_CHACHA_NONCESIZE {
+	if nonce.len() == IETF_CHACHA_NONCESIZE {
 		chacha20::encrypt(
 			&SecretKey::from_slice(&key).unwrap(),
 			&chacha20::Nonce::from_slice(&nonce).unwrap(),
@@ -44,7 +44,7 @@ pub fn chacha_test_runner(
 		)
 		.unwrap();
 	}
-	if nonce.len() == constants::XCHACHA_NONCESIZE {
+	if nonce.len() == XCHACHA_NONCESIZE {
 		xchacha20::encrypt(
 			&SecretKey::from_slice(&key).unwrap(),
 			&xchacha20::Nonce::from_slice(&nonce).unwrap(),