fix: handle wasm compiliaton

Cargo.toml

@@ -23,14 +23,16 @@ signature = { version = "=2.3.0-pre.4", default-features = false, features = ["a
 spki = { version = "0.8.0-rc.1", default-features = false, features = ["alloc"] }
 zeroize = { version = "1.5", features = ["alloc"] }
 crypto-bigint = { version = "0.6.0-rc.6", default-features = false, features = ["zeroize", "alloc"] }
-crypto-primes = { version = "0.6.0-pre.2" }
+crypto-primes = { version = "0.6.0-pre.2", default-features = false }
+libm = "0.2"
 
 # optional dependencies
 sha1 = { version = "=0.11.0-pre.4", optional = true, default-features = false, features = ["oid"] }
 serdect = { version = "0.2.0", optional = true }
 sha2 = { version = "=0.11.0-pre.4", optional = true, default-features = false, features = ["oid"] }
 serde = { version = "1.0.184", optional = true, default-features = false, features = ["derive"] }
 
+
 [dev-dependencies]
 base64ct = { version = "1", features = ["alloc"] }
 hex-literal = "0.4.1"
@@ -56,6 +58,7 @@ pem = ["pkcs1/pem", "pkcs8/pem"]
 pkcs5 = ["pkcs8/encryption"]
 std = ["digest/std", "pkcs1/std", "pkcs8/std", "rand_core/std", "signature/std", "crypto-bigint/rand"]
 
+
 [package.metadata.docs.rs]
 features = ["std", "pem", "serde", "hazmat", "sha2"]
 rustdoc-args = ["--cfg", "docsrs"]

src/algorithms/generate.rs

@@ -42,7 +42,10 @@ pub(crate) fn generate_multi_prime_key_with_exp<R: CryptoRngCore>(
         let prime_limit = (1u64 << (bit_size / nprimes) as u64) as f64;
 
         // pi aproximates the number of primes less than prime_limit
+        #[cfg(feature = "std")]
         let mut pi = prime_limit / (prime_limit.ln() - 1f64);
+        #[cfg(not(feature = "std"))]
+        let mut pi = prime_limit / (libm::logf(prime_limit as f32) as f64 - 1f64);
         // Generated primes start with 0b11, so we can only use a quarter of them.
         pi /= 4f64;
         // Use a factor of two to ensure that key generation terminates in a