diff --git a/Libraries/LibCrypto/PK/PK.h b/Libraries/LibCrypto/PK/PK.h
index 4e24f4a2af7..baa4ae81c83 100644
--- a/Libraries/LibCrypto/PK/PK.h
+++ b/Libraries/LibCrypto/PK/PK.h
@@ -232,11 +232,11 @@ public:
 
     PKSystem() = default;
 
-    virtual void encrypt(ReadonlyBytes in, Bytes& out) = 0;
-    virtual void decrypt(ReadonlyBytes in, Bytes& out) = 0;
+    virtual ErrorOr<void> encrypt(ReadonlyBytes in, Bytes& out) = 0;
+    virtual ErrorOr<void> decrypt(ReadonlyBytes in, Bytes& out) = 0;
 
-    virtual void sign(ReadonlyBytes in, Bytes& out) = 0;
-    virtual void verify(ReadonlyBytes in, Bytes& out) = 0;
+    virtual ErrorOr<void> verify(ReadonlyBytes in, Bytes& out) = 0;
+    virtual ErrorOr<void> sign(ReadonlyBytes in, Bytes& out) = 0;
 
     virtual ByteString class_name() const = 0;
 
diff --git a/Libraries/LibCrypto/PK/RSA.cpp b/Libraries/LibCrypto/PK/RSA.cpp
index 4032636b7d4..af7c9d580a0 100644
--- a/Libraries/LibCrypto/PK/RSA.cpp
+++ b/Libraries/LibCrypto/PK/RSA.cpp
@@ -136,25 +136,21 @@ ErrorOr<RSA::KeyPairType> RSA::generate_key_pair(size_t bits, IntegerType e)
     return keys;
 }
 
-void RSA::encrypt(ReadonlyBytes in, Bytes& out)
+ErrorOr<void> RSA::encrypt(ReadonlyBytes in, Bytes& out)
 {
     dbgln_if(CRYPTO_DEBUG, "in size: {}", in.size());
     auto in_integer = UnsignedBigInteger::import_data(in.data(), in.size());
-    if (!(in_integer < m_public_key.modulus())) {
-        dbgln("value too large for key");
-        out = {};
-        return;
-    }
+    if (in_integer >= m_public_key.modulus())
+        return Error::from_string_literal("Data too large for key");
+
     auto exp = NumberTheory::ModularPower(in_integer, m_public_key.public_exponent(), m_public_key.modulus());
     auto size = exp.export_data(out);
     auto outsize = out.size();
-    if (size != outsize) {
-        dbgln("POSSIBLE RSA BUG!!! Size mismatch: {} requested but {} bytes generated", outsize, size);
-        out = out.slice(outsize - size, size);
-    }
+    VERIFY(size == outsize);
+    return {};
 }
 
-void RSA::decrypt(ReadonlyBytes in, Bytes& out)
+ErrorOr<void> RSA::decrypt(ReadonlyBytes in, Bytes& out)
 {
     auto in_integer = UnsignedBigInteger::import_data(in.data(), in.size());
 
@@ -178,22 +174,25 @@ void RSA::decrypt(ReadonlyBytes in, Bytes& out)
     for (auto i = size; i < aligned_size; ++i)
         out[out.size() - i - 1] = 0; // zero the non-aligned values
     out = out.slice(out.size() - aligned_size, aligned_size);
+    return {};
 }
 
-void RSA::sign(ReadonlyBytes in, Bytes& out)
+ErrorOr<void> RSA::sign(ReadonlyBytes in, Bytes& out)
 {
     auto in_integer = UnsignedBigInteger::import_data(in.data(), in.size());
     auto exp = NumberTheory::ModularPower(in_integer, m_private_key.private_exponent(), m_private_key.modulus());
     auto size = exp.export_data(out);
     out = out.slice(out.size() - size, size);
+    return {};
 }
 
-void RSA::verify(ReadonlyBytes in, Bytes& out)
+ErrorOr<void> RSA::verify(ReadonlyBytes in, Bytes& out)
 {
     auto in_integer = UnsignedBigInteger::import_data(in.data(), in.size());
     auto exp = NumberTheory::ModularPower(in_integer, m_public_key.public_exponent(), m_public_key.modulus());
     auto size = exp.export_data(out);
     out = out.slice(out.size() - size, size);
+    return {};
 }
 
 void RSA::import_private_key(ReadonlyBytes bytes, bool pem)
@@ -258,19 +257,15 @@ void RSA::import_public_key(ReadonlyBytes bytes, bool pem)
     m_public_key = maybe_key.release_value().public_key;
 }
 
-void RSA_PKCS1_EME::encrypt(ReadonlyBytes in, Bytes& out)
+ErrorOr<void> RSA_PKCS1_EME::encrypt(ReadonlyBytes in, Bytes& out)
 {
     auto mod_len = (m_public_key.modulus().trimmed_length() * sizeof(u32) * 8 + 7) / 8;
     dbgln_if(CRYPTO_DEBUG, "key size: {}", mod_len);
-    if (in.size() > mod_len - 11) {
-        dbgln("message too long :(");
-        out = out.trim(0);
-        return;
-    }
-    if (out.size() < mod_len) {
-        dbgln("output buffer too small");
-        return;
-    }
+    if (in.size() > mod_len - 11)
+        return Error::from_string_literal("Message too long");
+
+    if (out.size() < mod_len)
+        return Error::from_string_literal("Output buffer too small");
 
     auto ps_length = mod_len - in.size() - 3;
     Vector<u8, 8096> ps;
@@ -294,60 +289,47 @@ void RSA_PKCS1_EME::encrypt(ReadonlyBytes in, Bytes& out)
 
     dbgln_if(CRYPTO_DEBUG, "padded output size: {} buffer size: {}", 3 + ps_length + in.size(), out.size());
 
-    RSA::encrypt(out, out);
+    TRY(RSA::encrypt(out, out));
+    return {};
 }
-void RSA_PKCS1_EME::decrypt(ReadonlyBytes in, Bytes& out)
+
+ErrorOr<void> RSA_PKCS1_EME::decrypt(ReadonlyBytes in, Bytes& out)
 {
     auto mod_len = (m_public_key.modulus().trimmed_length() * sizeof(u32) * 8 + 7) / 8;
-    if (in.size() != mod_len) {
-        dbgln("decryption error: wrong amount of data: {}", in.size());
-        out = out.trim(0);
-        return;
-    }
+    if (in.size() != mod_len)
+        return Error::from_string_literal("Invalid input size");
 
-    RSA::decrypt(in, out);
+    TRY(RSA::decrypt(in, out));
 
-    if (out.size() < RSA::output_size()) {
-        dbgln("decryption error: not enough data after decryption: {}", out.size());
-        out = out.trim(0);
-        return;
-    }
+    if (out.size() < RSA::output_size())
+        return Error::from_string_literal("Not enough data after decryption");
 
-    if (out[0] != 0x00) {
-        dbgln("invalid padding byte 0 : {}", out[0]);
-        return;
-    }
-
-    if (out[1] != 0x02) {
-        dbgln("invalid padding byte 1 : {}", out[1]);
-        return;
-    }
+    if (out[0] != 0x00 || out[1] != 0x02)
+        return Error::from_string_literal("Invalid padding");
 
     size_t offset = 2;
     while (offset < out.size() && out[offset])
         ++offset;
 
-    if (offset == out.size()) {
-        dbgln("garbage data, no zero to split padding");
-        return;
-    }
+    if (offset == out.size())
+        return Error::from_string_literal("Garbage data, no zero to split padding");
 
     ++offset;
 
-    if (offset - 3 < 8) {
-        dbgln("PS too small");
-        return;
-    }
+    if (offset - 3 < 8)
+        return Error::from_string_literal("PS too small");
 
     out = out.slice(offset, out.size() - offset);
+    return {};
 }
 
-void RSA_PKCS1_EME::sign(ReadonlyBytes, Bytes&)
+ErrorOr<void> RSA_PKCS1_EME::sign(ReadonlyBytes, Bytes&)
 {
-    dbgln("FIXME: RSA_PKCS_EME::sign");
+    return Error::from_string_literal("FIXME: RSA_PKCS_EME::sign");
 }
-void RSA_PKCS1_EME::verify(ReadonlyBytes, Bytes&)
+
+ErrorOr<void> RSA_PKCS1_EME::verify(ReadonlyBytes, Bytes&)
 {
-    dbgln("FIXME: RSA_PKCS_EME::verify");
+    return Error::from_string_literal("FIXME: RSA_PKCS_EME::verify");
 }
 }
diff --git a/Libraries/LibCrypto/PK/RSA.h b/Libraries/LibCrypto/PK/RSA.h
index 11b127aed6d..4706ce5772b 100644
--- a/Libraries/LibCrypto/PK/RSA.h
+++ b/Libraries/LibCrypto/PK/RSA.h
@@ -195,11 +195,11 @@ public:
         m_public_key.set(m_private_key.modulus(), m_private_key.public_exponent());
     }
 
-    virtual void encrypt(ReadonlyBytes in, Bytes& out) override;
-    virtual void decrypt(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> encrypt(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> decrypt(ReadonlyBytes in, Bytes& out) override;
 
-    virtual void sign(ReadonlyBytes in, Bytes& out) override;
-    virtual void verify(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> verify(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> sign(ReadonlyBytes in, Bytes& out) override;
 
     virtual ByteString class_name() const override
     {
@@ -232,11 +232,11 @@ public:
 
     ~RSA_PKCS1_EME() = default;
 
-    virtual void encrypt(ReadonlyBytes in, Bytes& out) override;
-    virtual void decrypt(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> encrypt(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> decrypt(ReadonlyBytes in, Bytes& out) override;
 
-    virtual void sign(ReadonlyBytes, Bytes&) override;
-    virtual void verify(ReadonlyBytes, Bytes&) override;
+    virtual ErrorOr<void> verify(ReadonlyBytes in, Bytes& out) override;
+    virtual ErrorOr<void> sign(ReadonlyBytes in, Bytes& out) override;
 
     virtual ByteString class_name() const override
     {
diff --git a/Libraries/LibTLS/HandshakeClient.cpp b/Libraries/LibTLS/HandshakeClient.cpp
index bd2b8502dde..a94c878bfba 100644
--- a/Libraries/LibTLS/HandshakeClient.cpp
+++ b/Libraries/LibTLS/HandshakeClient.cpp
@@ -195,7 +195,7 @@ void TLSv12::build_rsa_pre_master_secret(PacketBuilder& builder)
     Vector<u8, 32> out;
     out.resize(rsa.output_size());
     auto outbuf = out.span();
-    rsa.encrypt(m_context.premaster_key, outbuf);
+    MUST(rsa.encrypt(m_context.premaster_key, outbuf));
 
     if constexpr (TLS_DEBUG) {
         dbgln("Encrypted: ");
diff --git a/Libraries/LibTLS/HandshakeServer.cpp b/Libraries/LibTLS/HandshakeServer.cpp
index a84806c24ef..cef2fe0ea1f 100644
--- a/Libraries/LibTLS/HandshakeServer.cpp
+++ b/Libraries/LibTLS/HandshakeServer.cpp
@@ -388,7 +388,7 @@ ssize_t TLSv12::verify_rsa_server_key_exchange(ReadonlyBytes server_key_info_buf
     }
     auto signature_verify_buffer = signature_verify_buffer_result.release_value();
     auto signature_verify_bytes = signature_verify_buffer.bytes();
-    rsa.verify(signature, signature_verify_bytes);
+    MUST(rsa.verify(signature, signature_verify_bytes));
 
     auto message_result = ByteBuffer::create_uninitialized(64 + server_key_info_buffer.size());
     if (message_result.is_error()) {
diff --git a/Libraries/LibTLS/TLSv12.cpp b/Libraries/LibTLS/TLSv12.cpp
index d4517d7074c..86b196a049e 100644
--- a/Libraries/LibTLS/TLSv12.cpp
+++ b/Libraries/LibTLS/TLSv12.cpp
@@ -352,7 +352,7 @@ bool Context::verify_certificate_pair(Certificate const& subject, Certificate co
         }
         auto verification_buffer = verification_buffer_result.release_value();
         auto verification_buffer_bytes = verification_buffer.bytes();
-        rsa.verify(subject.signature_value, verification_buffer_bytes);
+        MUST(rsa.verify(subject.signature_value, verification_buffer_bytes));
 
         ReadonlyBytes message = subject.tbs_asn1.bytes();
         auto pkcs1 = Crypto::PK::EMSA_PKCS1_V1_5<Crypto::Hash::Manager>(kind);
diff --git a/Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp b/Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp
index df50b2ca4df..b3eb9c2a121 100644
--- a/Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp
+++ b/Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp
@@ -691,7 +691,9 @@ WebIDL::ExceptionOr<GC::Ref<JS::ArrayBuffer>> RSAOAEP::encrypt(AlgorithmParams c
     auto ciphertext_bytes = ciphertext.bytes();
 
     auto rsa = ::Crypto::PK::RSA { public_key };
-    rsa.encrypt(padding, ciphertext_bytes);
+    auto maybe_encrypt_error = rsa.encrypt(padding, ciphertext_bytes);
+    if (maybe_encrypt_error.is_error())
+        return WebIDL::OperationError::create(realm, "Failed to encrypt"_string);
 
     // 6. Return the result of creating an ArrayBuffer containing ciphertext.
     return JS::ArrayBuffer::create(realm, move(ciphertext));
@@ -723,7 +725,9 @@ WebIDL::ExceptionOr<GC::Ref<JS::ArrayBuffer>> RSAOAEP::decrypt(AlgorithmParams c
 
     auto padding = TRY_OR_THROW_OOM(vm, ByteBuffer::create_uninitialized(private_key_length));
     auto padding_bytes = padding.bytes();
-    rsa.decrypt(ciphertext, padding_bytes);
+    auto maybe_encrypt_error = rsa.decrypt(ciphertext, padding_bytes);
+    if (maybe_encrypt_error.is_error())
+        return WebIDL::OperationError::create(realm, "Failed to encrypt"_string);
 
     auto error_message = MUST(String::formatted("Invalid hash function '{}'", hash));
     ErrorOr<ByteBuffer> maybe_plaintext = Error::from_string_view(error_message.bytes_as_string_view());
diff --git a/Tests/LibCrypto/TestOAEP.cpp b/Tests/LibCrypto/TestOAEP.cpp
index a19f8531ef9..96d696b49fc 100644
--- a/Tests/LibCrypto/TestOAEP.cpp
+++ b/Tests/LibCrypto/TestOAEP.cpp
@@ -137,7 +137,7 @@ TEST_CASE(test_oaep)
     auto output_buffer = maybe_output_buffer.release_value();
     auto output_span = output_buffer.bytes();
 
-    rsa.encrypt(result, output_span);
+    TRY_OR_FAIL(rsa.encrypt(result, output_span));
 
     EXPECT_EQ(expected_rsa_value, output_span);
 }
diff --git a/Tests/LibCrypto/TestRSA.cpp b/Tests/LibCrypto/TestRSA.cpp
index 1e06ccb5cde..fba3c387961 100644
--- a/Tests/LibCrypto/TestRSA.cpp
+++ b/Tests/LibCrypto/TestRSA.cpp
@@ -28,7 +28,7 @@ TEST_CASE(test_RSA_raw_encrypt)
     ByteBuffer buffer = {};
     buffer.resize(rsa.output_size());
     auto buf = buffer.bytes();
-    rsa.encrypt(data, buf);
+    TRY_OR_FAIL(rsa.encrypt(data, buf));
     EXPECT(memcmp(result, buf.data(), buf.size()) == 0);
 }
 
@@ -42,8 +42,8 @@ TEST_CASE(test_RSA_PKCS_1_encrypt)
     ByteBuffer buffer = {};
     buffer.resize(rsa.output_size());
     auto buf = buffer.bytes();
-    rsa.encrypt(data, buf);
-    rsa.decrypt(buf, buf);
+    TRY_OR_FAIL(rsa.encrypt(data, buf));
+    TRY_OR_FAIL(rsa.decrypt(buf, buf));
 
     EXPECT(memcmp(buf.data(), "hellohellohellohellohellohellohellohellohello123-", 49) == 0);
 }
@@ -149,8 +149,8 @@ c8yGzl89pYST
 
     dec.overwrite(0, "WellHelloFriends", 16);
 
-    rsa_from_pair.encrypt(dec, enc);
-    rsa_from_pem.decrypt(enc, dec);
+    TRY_OR_FAIL(rsa_from_pair.encrypt(dec, enc));
+    TRY_OR_FAIL(rsa_from_pem.decrypt(enc, dec));
 
     EXPECT_EQ(memcmp(dec.data(), "WellHelloFriends", 16), 0);
 }
@@ -171,8 +171,8 @@ TEST_CASE(test_RSA_encrypt_decrypt)
 
     enc.overwrite(0, "WellHelloFriendsWellHelloFriendsWellHelloFriendsWellHelloFriends", 64);
 
-    rsa.encrypt(enc, dec);
-    rsa.decrypt(dec, enc);
+    TRY_OR_FAIL(rsa.encrypt(enc, dec));
+    TRY_OR_FAIL(rsa.decrypt(dec, enc));
 
     EXPECT(memcmp(enc.data(), "WellHelloFriendsWellHelloFriendsWellHelloFriendsWellHelloFriends", 64) == 0);
 }