crypto/src/main/java/org/springframework/security/crypto/password/MessageDigestPasswordEncoder.java
public String encode(CharSequence rawPassword) {
		String salt = PREFIX + this.saltGenerator.generateKey() + SUFFIX;
		return digest(salt, rawPassword);
	}
public String encode(CharSequence rawPassword) {
		String salt = PREFIX + this.saltGenerator.generateKey() + SUFFIX;
		return digest(salt, rawPassword);
	}
Encodes the rawPass using a MessageDigest. If a salt is specified it will be merged
with the password before encoding.

@param rawPassword The plain text password
@return Hex string of password digest (or base64 encoded string if
encodeHashAsBase64 is enabled.